I was able to do it without taking any plugs off. The speaker assembly just flipped over to the right upside-down. I did this last night. Took able 45 minutes. Thank you for showing me how and the locations. Replaced the clock battery too. 73, Bill KA2QEP
Hi Alan. Just wanted to say thanks for your video 309. Battery replacement in a TS-940S. I've been a Ham since age 12. Active and inactive over the last 65 yrs. My grandson's are showing and asking questions about amateur radio and electronics so I have recently set some radios on 2m to introduce them to local activities and Hams. I unboxed my TS 940s and put up a G5RV in the trees. I noticed my frequently and function monitor clock etc weren't working correctly. Went to RUclips for information and found your video 309. Just replaced the original batteries and now back in business thanks to you. TNX Ka2bec
BTW. the original Sanyo batteries were in place. The placement of the front panel batteries were negative to negative with the insulation material in-between. I replaces them in the same attitude as they were from factory. Didn't make a large difference than your description as long as negative and positive tabs went to their respective posts and diode. Carefully and slowly peeled off kenwood insulation and foam material from old batteries and stickum still worked transfered to new batteries. Just didn't have any insulation material on hand but original stuff worked perfectly. Amazing. I have assembled many heathkit products and repaired many drake B line radios but upon opening the 940 I was amazed as others have commented at the complex wiring and maze of parts. Still love this radio. My son still operates his 840. Only the main frequency selector dial doesn't turn as freely as when new but radio still works great. TNX KA2BEC
Man, the wiring looms in Kenwood radios always amaze me! putting those radios together must have been a hell of a thing.. also quite amazing seeing date codes of 1984 on the chips in the Radio. I hope some of my contemporary modern gear lasts 1/2 as long ... Thanks for another great video, Alan.
TS-940s is a legend. It is a very complex radio, but if you love this radio, you can repair it and even improve anytime. Some time ago I refurbished mine, it took me one month of hard work, but the result is satisfacting. Most hams would probably buy a new rig, but I am keen enthusiast of classic 80's heavy analog rigs. I use my TS-940 almost daily and it always give me a lots of pleasure. 73 Jan
hi Alan, my name is Ari, I’m from Caxias do sul, south Brazil, I’ve been following your channel for many years. I learned many things and I was very encouraged in your videos, seeing your tranquility and your laboratory I acquired many tektronix , multimeters, devices, etc, for listening, observing. and learn from your knowledge in electronics, thanks for sharing and being so generous, don't stop with your videos that instruct and animate us.
I continue to keep up to date on this channel. Having seen them all, I have to say #153 has to be my favorite since the Kenwood TS-830S is my present radio. I recommend all hams have a look at this channel............huge knowledge base in these videos.
Before you close up your TS940S you should view The Radio Shop's "#247 Tech Tip Kenwood TS 940S Display". Simply reseating the eprom can save you a lot of future hassle due to an apparently dead S meter, and the dreaded intermittent "Display Dot Problem"!
Good job Alan...done that at least three times on my venerable TS-940S since I bought it new in 1986! Replacing the power supply with Compudigital's switcher supply will be a winter project. Another local has done that already and is pleased with the result...those AVR PS boards have an expiration date and I'd prefer not to have a catastrophic failure! 73 - Dino KL0S
I just recently upgraded from Technician to General Ham and have a working Kenwood TS-430S and a dedicated power supply PS-430. I will need to replace my battery very soon. Thanks for posting about the TS-940S. 73 from K9POW in eastern Tennessee.
I soldered a socket and replaced the battery with a CR2032. This works for a TS-440S, TS-50S and this TS-940S. On my TS-940S, the timer had only one battery. All devices have been working for over 4 years now. The advantage is that you get the CR2032 everywhere at a very low price. 73 Bernd
Glad to see another TS-940 in working condition. I noticed that one has the VS-1 tone board. On mine, (a two battery version) my batteries were still working but they were measuring a little over 2 volts. I went ahead and replaced them when I had it apart to install the IF-10B serial interface board. I attached CR2032 holders and put fresh batteries in them to make future replacement easier. Though, considering the previous ones lasted about 35 years, these may never need replacing. LOL
Thank you, outcoming clock battery was a CR2450, so using a CR2032 I needed to attach a small wire to the negative in order to solder them together. Due to the smaller size. If available I would use a CR2450 next time. Everything working fine again. Thanks and 73 from the Netherlands. What a building quality btw of the Kenwood, having a TS930S, a TS940S and a TS950 sdx you can say I like them very much!. Great rig, great video you have made.
Hello Alan, I hope you and your family is safe and healthy during this pandemic we are experiencing. I thoroughly enjoy your videos and the knowledge that you provide the greater community. 73, de kd5eax.
Hi Alan, ... Good to see you still "up & at 'em!" ... I was thrilled to see the article about you in QST. Bravo! (I made it a point to read the whole thing a couple of times ... just for QST's info). One thing I have appreciated, though, is that your videos on RUclips have a higher quality of content than some of the many other articles available. In the case of this video, though, it opens one's eyes as to just how to approach fixing stuff on the beautiful old TS-940. Back in the day, when I was whailing away at one of the old sunspot cycles at a furious rate, I was using the TS-940's older brother, the TS-820S. Unfortunately for me I had problems with it, that I could not figure out (no one else that I knew could figure them out either), and there was no internet or RUclips to help out. So, I really, really appreciate the resource you are providing. (My Dad passed away, and left myself and my brother (W7SN) his TS-940) I hope you live long and prosper! ... 73 & DX! ... Neil, K7WK
Thank you for the nice comment on the QST article. It was quite an honor to be selected. I really appreciate your nice comments on my video content. I'm sorry for the loss of your Dad - I've been there. 73, Alan
Hi Alan, I was wondering why my multifuntion digital display timer was not working. After seeing your video it was a big help to see the reason. Just wanted to say thank you for sharing. I did subscribe. :)
Had to do that to a TM-231A. Found a service manual online. You have to disassemble a crazy amount of the radio. Put the battery on wire leads from the pads so the next time, just clip easily accessible the wire and soldier. Shrink wrapped the battery so it would not short anything.
Thank you Alan, for a very good job and your very pleasant serenity. always a pleasure to watch your channel. i just finished my 2x TS940S and have batteries still for 20 years. 73 'of F-14989 swl Erick. and happy new year 2021
My dad poassed and left me his radio, it sat for 7 years and i finally decided to fire it up and it didn't work. Thanks to your video it showed me the exact error i was getting and the press AB button on start worked which means i need batteries as well. You wouldn't happen to know that batteries ( parts ) needed for this job ? and THANK YOU for posting the video
A clear explanation .. clear picture..you deserve a diamond for your way to explain things ... the importace home is to get to the module in question .. thank you de CN8MM
Thanks for the good video. Reminds me that I should change out the battery in my TS-450S/AT. Bought it in 2013 but no clue as to how long the battery has been in there.
You better do it soon. I had one that leaked and ate away some lands underneath it. Some hams have relocated it to a safer place and ran wires. 73, Bill KA2QEP
Since it's sitting there since 1985, I would make a backup from that EPROM, erase and reprogram it. I've seen EPROMs developing amnesia after just 20 years. To be fair, I've also seen some that were fine after 40+ years, but you never know when it will happen.
I installed low profile coin cell holders and higher capacity coin cells in my 940. No longer uses 2032's. Using Kapton tape works as well as foam insulation BTW.
I really enjoy the video's you give us. I know you have done some talks about RF and IF transformers, but I would like to see a in-depth look at power transformers, and would like to know what the difference of a winding side-by-side or each winding on top of each other. (radio transformers are mostly wound on top of each other, but a micro wave transformer is side by side windings). If you are making a isolation transformer for 120vac of around 200+ turns, and wind 200 on top for the output, the wire in the secondary will be longer because of the amount of layers on top of the primary. There must be some kind of formula for all this stuff. Thank You
Nice video Alan. You installed the top battery on the timer board upside down, compared with how the original was installed. You even commented on it that positive was up, but then installed it negative up. I assume it was designed so that the bottom battery had negative up, and top battery negative down so they were on same side in case of a short.
When Alan changed the first lithium coin cell (solder tab), you may have noticed the Insulator (foam pad) on the lithium coin cell. Kenwood part number for that insulator is F20-0521-04 : $1.10 from Kenwood Parts. The late Bill Leahy, K0ZL (sk, February 2009) changed hundreds of Kenwood batteries, and provided alternatives (when Kenwood Parts were out of stock - a decade ago - due to Panasonic buyout of Sanyo and part number changes of Solder Tab suffix). forums.qrz.com/index.php?threads/ts-440s-battery-replacement.72950/
I got me a TS-940, was not working, so cheap. Power supply issues. Radio worked well except clock was running a mile a minute. Like 1 minute every 10 seconds. Was a dead battery. Changed them all. Recap unit and alignment. Unit works well. TS-430(I think) had bad battery and computer would lock up. Seems a kinda norm with Kenwood. low battery and it jacks on ya. I install a cr2032 socket when I can. P.S. the TS-940 has tendency, over time, attenuator relays get dirty. I replaced mine get signal level up.
It would be cool if you did a video explaining operation transconductance amplifiers (OTAs). They seem really useful but not much info on them, (at least on RUclips).
Thanks so much for this video. My sub-display (LCD) flickered for a day or so before it died. BatteryBob.com sells the precise batteries for the 940. I ordered 2, not knowing till I opened my 90000 series rig was one that had just 1 for the sub-display. I elected not to replace the main display battery at that time, but plan to do so soon. Gad, the wiring between the front panel and main chassis sure is daunting! I inherited my 940 (and my call) from my SK OM. I love keeping both on the air! W3PYF.
wires are really big pain in this construction, in ex ussr there were produced special military wires called MGTF they were made out of many very thin copper lines winded togetger in special tough insulation, they easily survive temperatures up to 200 and mechanical tension, those wires still on sale as second source supply they would make this device working without flaw
A quick question for you Alan. I was thinking about asking Santa for an isolation transformer for the bench. Are they worth it and if so can you recommend which one to get? Thanks for your help. I am a beginner electroniker.
Hi, I found the video very helpful but what's the battery numbers? I'll try Kenwood 1st, if that fails it must be ebay. Thanks again, I can now look forward to using my Trio TS-940S again after it's been in limbo for 10 years plus.
Nice video that should help some out. I know this sort of construction is the norm for this era of Japanese radios but your really have to wonder why they were, and to some degree still are, using such crude mostly 1960’s design methods? This radio could have been made with far fewer PCB’s, ribbon cables could have replaced the complete rat’s nest of discrete wire harnesses, etc. Such a radio would be cheaper to make, more reliable, and easier to service. If you look at an American designed radio, like an Elecraft, the engineering superiority is obvious.
Alan, why do manufacturers use batteries that need to be soldered to replace them, rather than just using standard AA batteries and an easily accessible battery holder? (BTW, I watch all your videos and learn something new every time)
Question for you: do those 22 channel 2-way radios use the same frequencies as ham radio? I was messing around with a set of Uniden radios today (not much else to do) and I was picking up a conversation between someone in a town about 30 miles from me, and someone else who said he was in a desert area (I'm in Michigan so nothing like that around here). My radios are rated for 6 miles max. It was channel 18 which is 462.6250 MHz. They said something about a repeater down in Illinois. (I couldn't transmit because the batteries are junk and the transmit wattage instantly makes them shut down with a low battery indicator, so all I can really do is receive.)
The radios you have are for GMRS. They do not use the same frequencies as ham radio. You need to have a license to transmit with them. There are GMRS repeaters. You were listening to a repeater output. More information here: en.m.wikipedia.org/wiki/General_Mobile_Radio_Service
Thank you so much for your videos, I love them. I'm searching for a specific passage, if I remember correctly you - at least - once stated that the RF input circuit of a spectrum analyzer is more stable if I use a e.g. 20 dB 50 Ohm Pad on it. I can't find this anymore... I'd like to know why that is. Do you remember where that was? I thought it was on the directional coupler video but I couldn't find it there...
I think I mentioned that when referring to using a Tracking Generator when looking at tuning a filter - using an attenuator on the output of the tracking generator ensures that *it* sees a more consistent 50 ohm load (even when the filter under test doesn't).
I am curious if you have any cool techniques to stay organized in the shop. I imagine you’ve collected quite a bit of stuff & parts & tools etc… As my collection grows I am finding trouble keeping sanity. For example right now I’m wishing I had a quick simple way to keep the ‘current’ parts on the bench without them being in a pile. If we put all the resistors in a little bin and keep that on the desk. It can get messy. esp the 4 bands with brown on BOTH sides !! or fast diodes/ zeners. Point is that there is a lot of components which look the same. My quick grab is a pile the desk and a large breadboard which I populate in order. Everything else is shelved and binned. Also, I am really curious if you have techniques for working with probes without them strewn about the desk(like mine). 4 or 8 probes , a couple of DMM’s and a signal generator will fill the desk with wires REAL quick. I have not found a solution for that yet. Anyways, I’m just making a suggestion that a video about “organizing the electronics bench” would be a cool topic. In the shop too. I’ve probably got all the types of storage bins known to man that they sell at home depot and target. 99c shoe boxes. Tool boxes. etc etc… I think the new players and old hats will likely find some things useful. Still wondering how you fit that 17m antenna in the shop.. haha jk
If you've seen my shop you'll know that I don't have a good organization system! I do have new/unused stock of resistors, caps, transistors, etc. in those plastic multi-drawer bins, and I do have several wire looms for probes and cables, but that's about it. My "go-to" pile of stuff on the bench is a mess!
@@w2aew I feel you pain too. Don't b so hard on yourself. In the EE shop its not about appearances but utility. I think all of us feel the struggle of stacks on stacks and piles on piles. I was laughing when one viewer commented "now I can sort my zeners" , in my mind I was imagining a toothpick jar sitting on the desk. Luv ur content, appreciate everything
hi, i have a kenwood ts950s and theres no readout,can you please help me whats wrong,check the backup battery and its dead,and try the reset it doesnt came back,even i replaced the back up cell and reset still no readout...thanks..
Hi Alan just say thanks just got blank display bleeps on my TS-940sat i was heartbroken thinking i was the main microprocessor it was the battery thanks for the info DE G7NPL
Thanks for posting the video how to replace the Kenwood TS-940 batteries! I have a non-functional TS-940. It had chirp on CW receive and garbled audio on SSB receive. Then the PLL quit working intermittently. Now the PLL doesn’t work at all. Do you know how to fix that problem? I heard that cleaning 60 plus tin plated molex connectors and resoldering several PC boards might fix that problem. The TS-940 is notorious for bad soldered PC boards. Dave KY0L
I can confirm this. Reseating the connectors is the first thing you should do. Muffled audio and similar issues is due to leaking capacitors. You can purchase the capacitors set for TS-940 on ebay. Kenwood radios are notorious for leaking caps. I have the same issue on TS-850 too.
hello sir could you explain ,,, till what frequencies now we are using Silicon , what are the new materials which will help at high frequency ,as silicon did till now,,,, could you explain why VLSI and Microwave design differ a lot ???????
Thanks for the Battery information. My unit has been in storage for years. when I push my power button unit powers up , when you release the button it goes down Any suggestions ? If I hold the button in radio works < any way to test switch ?
Does the power switch stay depressed when you let it go, like a bic-click pen? Or is it returning to the full protruded position? This power button should work like a retractable pen. Push til it clicks and it stays depressed, push again and it returns out and turns off. If it doesn't stay in, then is sounds like a gummed up mechanical issue. If it stays in, but the radio turns off, then maybe dirty contacts or bad solder joint at the switch.
@@w2aew Thank you for reply ... The switch does not stay in. Where is the best place to order battery's from . Can the switch be cleaned or just replace. Thank you
@@brucecasey4252 I got them from pacparts.com to be sure that they had the tabs soldered on them. You might as well get a new switch as the same time so that you make the shipping charge worth it.
What are the P/N's for the batteries replaced? Are all three the same kind of battery? If OEM is not available, is there a suitable replacement that will work? DE KB9ECQ
In a nice piece like this so delicate and complicated why would they put in batteries? Isn't there something they could use instead like a standby voltage or something? Well this is above my pay (I am an old retired fart) but I do like to watch folks play with these cool toys.. thanks for the share, carry on and have fun doing so!
@@w2aew Geez it looks like something new to me.. like about 5 or so years old maybe.. But then I do not do any of that ham stuff.. Not that I am not interested in it, it's just I was so busy in my young life that I never settled down enough to get into it.. then had a family and now I am old and on a fixed income.. But I am trying to teach myself a little electronics with all these break out boards, pi's, arduinos and such.. That is why I like your channel.. you are a very good teacher.. even an old fart like me can follow what you are saying.. thank you I appreciate all of your hard work! Carry on!
@@w2aew Wow.. that was a while back.. I was settle down then.. sure looks in great condition but then I look ok 32 years ago when I was 35 also.. with with a wife and a couple of babies.. you do great work son.. thanks!
I'm sorry, I don't offer repair services. I used to recommend Cliff from AAVID in Texas, but I think he retired. If you have a somewhat local ham radio store, they might be able to recommend someone since they probably get asked a lot.
Lithium batteries. The only thing I dislike more than leaky capacitors. I sympathize with the engineers a little bit on mobile radios, but in a radio like this, with all of the available space, I don’t see why they didn’t relocate those batteries to easier to get to locations, or even used spring loaded battery holders like you see on many PC boards.
The Batteries Capacity is what determines the batteries discharge rate of the speed of the current? The batteries current is "dissipating" each time you apply a load to the battery, the discharge rate of the current is determined on what?
This is something that YOU can likely correct (assuming that it is just the frequency accuracy that is off). Here is a procedure I wrote many years ago: www.qsl.net/w2aew/adjustrig.htm
Can somebody tell me what are those 2 components with 4 strips on 1:18 at the bottom center of the screen? Are those resistors or inductors? I pulled out few of those from old device, but resistence reading is ~0.5 ohm.
is it possible to make a video about analog signal generators? once you showed one saying you made it many years ago. can we get a series like how to design, make analog function generator, or how you made yours, maybe a schematic walk through. I know today I can get an IC and use some precision opamps, but analog sounds more interesting :)
You have so many cool notes, way better than college lecture notes. Is there a way to have the notes you use on the videos available as pdf for us to use and download? That'd be super awesome! 73
Notes for most of my videos *are* available as PDF downloads already! If available, there is a link in the video description (you have to hit the "SHOW MORE" link...
w2aew, How do you measure the DC internal resistance of a 9 volt battery using what kind of meter? Carbon Zinc batteries have a higher DC internal Resistance compared to Alkaline batteries and Mercury Batteries which the DC internal Resistance puts a LOAD or changes the impedance of the power rails? its "adding" an additional resistances to the circuit?
The general method would be to measure the battery voltage with nothing connected, then connect a small resistor and measure the battery voltage again. You can calculate the internal resistance from these two values. To make it easy, adjust the resistor until the voltage is 1/2 of the open-circuit voltage. Then, the internal resistance is equal to the applied resistor.
9volt battery and adjust the resistor across the battery terminals until its 4.5 volts and that batterys DC internal resistance. This DC internal resistance is "in series" with the circuit which causes "loading" on the power rails and changes the impedance of the +Vcc?
Why does different battery types like alkaline batteries, carbon zinc, lithium, mercury batteries all have a different DC internal resistance value? What I mean is what is causes the DC internal resistance in battery is it the cells in series that creates the internal resistance in batteries?
Simple job hindered by a pile of loose cables :-) Is it just me (or the camera angle), or the positive terminal of the first battery behind the LCD display, at 4:30, is not completely soldered?
Hello Alan! I absolutely love your content, please keep up the good work, and greetings from Germany. :) My guitar amp recently started picking up signals from a nearby cell tower. The tower just started to use 5G i believe, because the tower isn't new and i had no interference problems before. Also the amp works just fine in a different room. Do you have any tipps on how i could effectifly shield my amp or what i can do about it? Maybe this could be something for a new video? :)
@@w2aew Thanks for the response! I saw your video on that already. The interefence only occurs when i engage the build in reverb tank. The chinch cable already had a ferrit bead on it. I put a second one on it but the interference unfortunately is still present. I noticed that when i lean over the amp in a certain way, the interference weakens. I guess my body then acts like a shield? Can i maybe get the same effect with some metal foil or so?
It is very simple. It takes longer to remove the top and bottom covers then it takes to replace the battery. With the top and bottom covers removed, loosen the lower screws holding the front panel and remove the top two. Rotate the front panel down and the battery is right there. See page 81 of the manual located here: www.radiomanual.info/schemi/KENW_HF/TS-870S_serv.pdf You might not even have to rotate the panel...
I was able to do it without taking any plugs off. The speaker assembly just flipped over to the right upside-down. I did this last night. Took able 45 minutes. Thank you for showing me how and the locations. Replaced the clock battery too. 73, Bill KA2QEP
Glad to hear that my video helped you out!
Hi Alan. Just wanted to say thanks for your video 309. Battery replacement in a TS-940S. I've been a Ham since age 12. Active and inactive over the last 65 yrs. My grandson's are showing and asking questions about amateur radio and electronics so I have recently set some radios on 2m to introduce them to local activities and Hams. I unboxed my TS 940s and put up a G5RV in the trees. I noticed my frequently and function monitor clock etc weren't working correctly. Went to RUclips for information and found your video 309. Just replaced the original batteries and now back in business thanks to you. TNX Ka2bec
BTW. the original Sanyo batteries were in place. The placement of the front panel batteries were negative to negative with the insulation material in-between. I replaces them in the same attitude as they were from factory. Didn't make a large difference than your description as long as negative and positive tabs went to their respective posts and diode. Carefully and slowly peeled off kenwood insulation and foam material from old batteries and stickum still worked transfered to new batteries. Just didn't have any insulation material on hand but original stuff worked perfectly. Amazing. I have assembled many heathkit products and repaired many drake B line radios but upon opening the 940 I was amazed as others have commented at the complex wiring and maze of parts. Still love this radio. My son still operates his 840. Only the main frequency selector dial doesn't turn as freely as when new but radio still works great. TNX KA2BEC
Man, the wiring looms in Kenwood radios always amaze me! putting those radios together must have been a hell of a thing.. also quite amazing seeing date codes of 1984 on the chips in the Radio. I hope some of my contemporary modern gear lasts 1/2 as long ...
Thanks for another great video, Alan.
TS-940s is a legend. It is a very complex radio, but if you love this radio, you can repair it and even improve anytime. Some time ago I refurbished mine, it took me one month of hard work, but the result is satisfacting. Most hams would probably buy a new rig, but I am keen enthusiast of classic 80's heavy analog rigs. I use my TS-940 almost daily and it always give me a lots of pleasure. 73 Jan
hi Alan, my name is Ari, I’m from Caxias do sul, south Brazil, I’ve been following your channel for many years. I learned many things and I was very encouraged in your videos, seeing your tranquility and your laboratory I acquired many tektronix , multimeters, devices, etc, for listening, observing. and learn from your knowledge in electronics, thanks for sharing and being so generous, don't stop with your videos that instruct and animate us.
Olá Ari, você possui um 940s? 73's Pu2MPF
I continue to keep up to date on this channel. Having seen them all, I have to say #153 has to be my favorite since the Kenwood TS-830S is my present radio. I recommend all hams have a look at this channel............huge knowledge base in these videos.
Tks OM. Couldn't have done it without your expert advice.
Before you close up your TS940S you should view The Radio Shop's "#247 Tech Tip Kenwood TS 940S Display". Simply reseating the eprom can save you a lot of future hassle due to an apparently dead S meter, and the dreaded intermittent "Display Dot Problem"!
Thank you kindly! Following his procedure, I was able to get my TS-940 back up and running.
Good job Alan...done that at least three times on my venerable TS-940S since I bought it new in 1986! Replacing the power supply with Compudigital's switcher supply will be a winter project. Another local has done that already and is pleased with the result...those AVR PS boards have an expiration date and I'd prefer not to have a catastrophic failure! 73 - Dino KL0S
Dino i do the same with compudigital mod. And is AMAZING results. It is alive !!!!
@@lampa2001 I completed the power supply, batteries and LED replacements last month and am very pleased with the result! 73 - Dino KLØS
I just recently upgraded from Technician to General Ham and have a working Kenwood TS-430S and a dedicated power supply PS-430. I will need to replace my battery very soon. Thanks for posting about the TS-940S. 73 from K9POW in eastern Tennessee.
I soldered a socket and replaced the battery with a CR2032. This works for a TS-440S, TS-50S and this TS-940S. On my TS-940S, the timer had only one battery.
All devices have been working for over 4 years now. The advantage is that you get the CR2032 everywhere at a very low price.
73 Bernd
Enjoyable video and appreciate all your comments.
Thanks. Will be replacing the batt in my 440S soon. This was helpful.
I suggest to backup, erase and reprogram all the EPROMs as well.
Glad to see another TS-940 in working condition. I noticed that one has the VS-1 tone board.
On mine, (a two battery version) my batteries were still working but they were measuring a little over 2 volts. I went ahead and replaced them when I had it apart to install the IF-10B serial interface board. I attached CR2032 holders and put fresh batteries in them to make future replacement easier. Though, considering the previous ones lasted about 35 years, these may never need replacing. LOL
Display was blank so thanks to your video I pressed the reset button and it started working fine again, thank you!, thank you!, thank you!
Thank you, outcoming clock battery was a CR2450, so using a CR2032 I needed to attach a small wire to the negative in order to solder them together. Due to the smaller size. If available I would use a CR2450 next time. Everything working fine again. Thanks and 73 from the Netherlands. What a building quality btw of the Kenwood, having a TS930S, a TS940S and a TS950 sdx you can say I like them very much!. Great rig, great video you have made.
Beautiful device - engineering and manufacturing these must have been quite the project.
Hello Alan, I hope you and your family is safe and healthy during this pandemic we are experiencing. I thoroughly enjoy your videos and the knowledge that you provide the greater community.
73, de kd5eax.
Hi Alan, ... Good to see you still "up & at 'em!" ... I was thrilled to see the article about you in QST. Bravo! (I made it a point to read the whole thing a couple of times ... just for QST's info). One thing I have appreciated, though, is that your videos on RUclips have a higher quality of content than some of the many other articles available. In the case of this video, though, it opens one's eyes as to just how to approach fixing stuff on the beautiful old TS-940. Back in the day, when I was whailing away at one of the old sunspot cycles at a furious rate, I was using the TS-940's older brother, the TS-820S. Unfortunately for me I had problems with it, that I could not figure out (no one else that I knew could figure them out either), and there was no internet or RUclips to help out. So, I really, really appreciate the resource you are providing. (My Dad passed away, and left myself and my brother (W7SN) his TS-940) I hope you live long and prosper! ... 73 & DX! ... Neil, K7WK
Thank you for the nice comment on the QST article. It was quite an honor to be selected. I really appreciate your nice comments on my video content. I'm sorry for the loss of your Dad - I've been there. 73,
Alan
Hi Alan, I was wondering why my multifuntion digital display timer was not working. After seeing your video it was a big help to see the reason. Just wanted to say thank you for sharing. I did subscribe. :)
I had to do that for a friend. Also rebuilt the power supply board, the capacitors were in need of replacement, DC supplies were noisy.
Now I’m no ham, but boy is that some really nice engineering on that radio.
Hello one more subscriber !!! I came through the WR. KITS !!!! strong hug!!!! come 2020 !!!
Had to do that to a TM-231A. Found a service manual online. You have to disassemble a crazy amount of the radio. Put the battery on wire leads from the pads so the next time, just clip easily accessible the wire and soldier. Shrink wrapped the battery so it would not short anything.
Yes, I had to do that to my TM-231A about 10 years ago too.
I found you from an Applied Sciences recommendation. I'm glad I found your channel.
Great! Ben is a brilliant guy - so nice to hear he's recommending my channel.
What a great looking radio! Thanks for showing us how to do this.
Thank you Alan, for a very good job and your very pleasant serenity. always a pleasure to watch your channel. i just finished my 2x TS940S and have batteries still for 20 years. 73 'of F-14989 swl Erick. and happy new year 2021
Geez... You just reminded me to make sure I cook up the spaghetti tonight for dinner. You performed that procedure like a seasoned surgeon!
Please don't be a stranger! We really need your electronics lessons!!!
From Russia with love!
Thank you for all the videos you made on youtube, it was a great help to me.
Very appreciate
Starting 2020 with an excellent video! Thank you and keep up the great content!
My dad poassed and left me his radio, it sat for 7 years and i finally decided to fire it up and it didn't work. Thanks to your video it showed me the exact error i was getting and the press AB button on start worked which means i need batteries as well. You wouldn't happen to know that batteries ( parts ) needed for this job ? and THANK YOU for posting the video
Call pacparts. They can tell you and sell you the parts. www.pacparts.com/default.cfm
A clear explanation .. clear picture..you deserve a diamond for your way to explain things ... the importace home is to get to the module in question .. thank you de CN8MM
We miss your words! We miss your handwriten notes! We miss your VNA and your 3M breadboard! Hope you're fine. Greetings from Portugal
Thank you - I"ll be back.... ....just a lot going on now. I have a pile of video topics that I hope to return to soon...
I like this channel by indicating WRkits channel
Super nice setup loving it keep up the good work!😍
Thanks for the good video. Reminds me that I should change out the battery in my TS-450S/AT. Bought it in 2013 but no clue as to how long the battery has been in there.
You better do it soon. I had one that leaked and ate away some lands underneath it. Some hams have relocated it to a safer place and ran wires. 73, Bill KA2QEP
great video. I wish you had posted in the part numbers you use in your comment section.
Since it's sitting there since 1985, I would make a backup from that EPROM, erase and reprogram it. I've seen EPROMs developing amnesia after just 20 years. To be fair, I've also seen some that were fine after 40+ years, but you never know when it will happen.
How does one back up the EPROM?
I installed low profile coin cell holders and higher capacity coin cells in my 940. No longer uses 2032's. Using Kapton tape works as well as foam insulation BTW.
I really enjoy the video's you give us.
I know you have done some talks about RF and IF transformers, but I would like to see a in-depth look at power transformers, and would like to know what the difference of a winding side-by-side or each winding on top of each other. (radio transformers are mostly wound on top of each other, but a micro wave transformer is side by side windings).
If you are making a isolation transformer for 120vac of around 200+ turns, and wind 200 on top for the output, the wire in the secondary will be longer because of the amount of layers on top of the primary. There must be some kind of formula for all this stuff.
Thank You
Thanks for your help and enjoyed your videos
Happy New Year To All. I signed up on WRKITS recommendation
Nice video Alan. You installed the top battery on the timer board upside down, compared with how the original was installed. You even commented on it that positive was up, but then installed it negative up. I assume it was designed so that the bottom battery had negative up, and top battery negative down so they were on same side in case of a short.
It was mainly because the lead on the diode was short and wouldn’t reach the batter terminal if it came off of the top.
Thanks, very informative, regards from carl.
Thank you for sharing all your expertise. You cover a lot of areas. I am new to your posts. 73, Bill KA2QEP
When Alan changed the first lithium coin cell (solder tab),
you may have noticed the Insulator (foam pad) on the lithium coin cell.
Kenwood part number for that insulator is F20-0521-04 : $1.10 from Kenwood Parts.
The late Bill Leahy, K0ZL (sk, February 2009) changed hundreds of Kenwood batteries,
and provided alternatives (when Kenwood Parts were out of stock - a decade ago -
due to Panasonic buyout of Sanyo and part number changes of Solder Tab suffix).
forums.qrz.com/index.php?threads/ts-440s-battery-replacement.72950/
Excellent video...
Great video. great instruction. Thank you.
I got me a TS-940, was not working, so cheap. Power supply issues. Radio worked well except clock was running a mile a minute. Like 1 minute every 10 seconds. Was a dead battery. Changed them all. Recap unit and alignment. Unit works well. TS-430(I think) had bad battery and computer would lock up. Seems a kinda norm with Kenwood. low battery and it jacks on ya. I install a cr2032 socket when I can. P.S. the TS-940 has tendency, over time, attenuator relays get dirty. I replaced mine get signal level up.
What do you have in your bag of tricks to narrow down reflected power problems In an RF power amplifier. Besides the normal heat buildup?
@w2aew Good to see you're still making videos
It would be cool if you did a video explaining operation transconductance amplifiers (OTAs). They seem really useful but not much info on them, (at least on RUclips).
Jonathan Kayne
Yes!!
Thanks so much for this video. My sub-display (LCD) flickered for a day or so before it died. BatteryBob.com sells the precise batteries for the 940. I ordered 2, not knowing till I opened my 90000 series rig was one that had just 1 for the sub-display. I elected not to replace the main display battery at that time, but plan to do so soon. Gad, the wiring between the front panel and main chassis sure is daunting! I inherited my 940 (and my call) from my SK OM. I love keeping both on the air! W3PYF.
Hallo, do you have the part number for the batteries, so I can order them in advnce? Thanks
Thank you very much for sharing this information! 73
Thanks for everything.
Hi, I'm a new subscriber nominated by Wagner Rambo from Wr Kits.
👍👍👍
Two obvious comments: 1- Good job (as usual); 2- Certainly I'll never buy one of those radio!
You know not only Tektronix devices but Kenwood’s transceivers ! Impressive...
wires are really big pain in this construction, in ex ussr there were produced special military wires called MGTF they were made out of many very thin copper lines winded togetger in special tough insulation, they easily survive temperatures up to 200 and mechanical tension, those wires still on sale as second source supply they would make this device working without flaw
I noticed felt pad washers on the round head screws holding down the PWBs, are these for vibration damping?
Merry Christmas and Happy New Year Alan all the best to you in the new year *Cheers* *73*
Very Nice!
Thanks.
A quick question for you Alan. I was thinking about asking Santa for an isolation transformer for the bench. Are they worth it and if so can you recommend which one to get? Thanks for your help. I am a beginner electroniker.
Hi, I found the video very helpful but what's the battery numbers? I'll try Kenwood 1st, if that fails it must be ebay. Thanks again, I can now look forward to using my Trio TS-940S again after it's been in limbo for 10 years plus.
That is one hell of a spaghetti bowl.
Has Yours TS-940S a point's on a VFD display?
awesome. I like your channel.
Thanks Alan!
Nice video that should help some out. I know this sort of construction is the norm for this era of Japanese radios but your really have to wonder why they were, and to some degree still are, using such crude mostly 1960’s design methods? This radio could have been made with far fewer PCB’s, ribbon cables could have replaced the complete rat’s nest of discrete wire harnesses, etc. Such a radio would be cheaper to make, more reliable, and easier to service. If you look at an American designed radio, like an Elecraft, the engineering superiority is obvious.
This is pretty typical of consumer electronics from the early to mid-80s.
Alan, why do manufacturers use batteries that need to be soldered to replace them, rather than just using standard AA batteries and an easily accessible battery holder? (BTW, I watch all your videos and learn something new every time)
Question for you: do those 22 channel 2-way radios use the same frequencies as ham radio? I was messing around with a set of Uniden radios today (not much else to do) and I was picking up a conversation between someone in a town about 30 miles from me, and someone else who said he was in a desert area (I'm in Michigan so nothing like that around here). My radios are rated for 6 miles max. It was channel 18 which is 462.6250 MHz. They said something about a repeater down in Illinois. (I couldn't transmit because the batteries are junk and the transmit wattage instantly makes them shut down with a low battery indicator, so all I can really do is receive.)
The radios you have are for GMRS. They do not use the same frequencies as ham radio. You need to have a license to transmit with them. There are GMRS repeaters. You were listening to a repeater output. More information here:
en.m.wikipedia.org/wiki/General_Mobile_Radio_Service
Thank you so much for your videos, I love them. I'm searching for a specific passage, if I remember correctly you - at least - once stated that the RF input circuit of a spectrum analyzer is more stable if I use a e.g. 20 dB 50 Ohm Pad on it. I can't find this anymore... I'd like to know why that is. Do you remember where that was? I thought it was on the directional coupler video but I couldn't find it there...
I think I mentioned that when referring to using a Tracking Generator when looking at tuning a filter - using an attenuator on the output of the tracking generator ensures that *it* sees a more consistent 50 ohm load (even when the filter under test doesn't).
Thank you!
I am curious if you have any cool techniques to stay organized in the shop. I imagine you’ve collected quite a bit of stuff & parts & tools etc… As my collection grows I am finding trouble keeping sanity. For example right now I’m wishing I had a quick simple way to keep the ‘current’ parts on the bench without them being in a pile. If we put all the resistors in a little bin and keep that on the desk. It can get messy. esp the 4 bands with brown on BOTH sides !! or fast diodes/ zeners. Point is that there is a lot of components which look the same. My quick grab is a pile the desk and a large breadboard which I populate in order. Everything else is shelved and binned. Also, I am really curious if you have techniques for working with probes without them strewn about the desk(like mine). 4 or 8 probes , a couple of DMM’s and a signal generator will fill the desk with wires REAL quick. I have not found a solution for that yet. Anyways, I’m just making a suggestion that a video about “organizing the electronics bench” would be a cool topic. In the shop too. I’ve probably got all the types of storage bins known to man that they sell at home depot and target. 99c shoe boxes. Tool boxes. etc etc… I think the new players and old hats will likely find some things useful. Still wondering how you fit that 17m antenna in the shop.. haha jk
If you've seen my shop you'll know that I don't have a good organization system! I do have new/unused stock of resistors, caps, transistors, etc. in those plastic multi-drawer bins, and I do have several wire looms for probes and cables, but that's about it. My "go-to" pile of stuff on the bench is a mess!
@@w2aew I feel you pain too. Don't b so hard on yourself. In the EE shop its not about appearances but utility. I think all of us feel the struggle of stacks on stacks and piles on piles. I was laughing when one viewer commented "now I can sort my zeners" , in my mind I was imagining a toothpick jar sitting on the desk. Luv ur content, appreciate everything
@@w2aew as long as there is a method to the madness, all is well.
TNX 4 another great video !
73 N8AUM
hi, i have a kenwood ts950s and theres no readout,can you please help me whats wrong,check the backup battery and its dead,and try the reset it doesnt came back,even i replaced the back up cell and reset still no readout...thanks..
Thank you. Glen, N0QFT
Hi Alan just say thanks just got blank display bleeps on my TS-940sat i was heartbroken thinking i was the main microprocessor
it was the battery thanks for the info DE G7NPL
Happy to help!
Thanks for posting the video how to replace the Kenwood TS-940 batteries! I have a non-functional TS-940. It had chirp on CW receive and garbled audio on SSB receive. Then the PLL quit working intermittently. Now the PLL doesn’t work at all. Do you know how to fix that problem? I heard that cleaning 60 plus tin plated molex connectors and resoldering several PC boards might fix that problem. The TS-940 is notorious for bad soldered PC boards.
Dave KY0L
Often, removing and re-seating the PCB connectors is enough.
I can confirm this. Reseating the connectors is the first thing you should do. Muffled audio and similar issues is due to leaking capacitors. You can purchase the capacitors set for TS-940 on ebay. Kenwood radios are notorious for leaking caps. I have the same issue on TS-850 too.
Good Job did 2
hello sir could you explain ,,, till what frequencies now we are using Silicon , what are the new materials which will help at high frequency ,as silicon did till now,,,,
could you explain why VLSI and Microwave design differ a lot ???????
Thanks for the Battery information. My unit has been in storage for years. when I push my power button unit powers up , when you release the button it goes down Any suggestions ? If I hold the button in radio works < any way to test switch ?
Does the power switch stay depressed when you let it go, like a bic-click pen? Or is it returning to the full protruded position? This power button should work like a retractable pen. Push til it clicks and it stays depressed, push again and it returns out and turns off. If it doesn't stay in, then is sounds like a gummed up mechanical issue. If it stays in, but the radio turns off, then maybe dirty contacts or bad solder joint at the switch.
@@w2aew Thank you for reply ... The switch does not stay in. Where is the best place to order battery's from . Can the switch be cleaned or just replace. Thank you
@@brucecasey4252 I got them from pacparts.com to be sure that they had the tabs soldered on them. You might as well get a new switch as the same time so that you make the shipping charge worth it.
@@w2aew Thank you Sir...
What are the P/N's for the batteries replaced? Are all three the same kind of battery? If OEM is not available, is there a suitable replacement that will work? DE KB9ECQ
The battery should be available from PacParts. They're either CR2430 or CR2032 type, 3V non-rechargable Lithium cells.
In a nice piece like this so delicate and complicated why would they put in batteries? Isn't there something they could use instead like a standby voltage or something? Well this is above my pay (I am an old retired fart) but I do like to watch folks play with these cool toys.. thanks for the share, carry on and have fun doing so!
Back in the era this equipment was made, electronic non-volatile storage devices were in their infancy, so they used battery backup to store data.
@@w2aew Geez it looks like something new to me.. like about 5 or so years old maybe.. But then I do not do any of that ham stuff.. Not that I am not interested in it, it's just I was so busy in my young life that I never settled down enough to get into it.. then had a family and now I am old and on a fixed income.. But I am trying to teach myself a little electronics with all these break out boards, pi's, arduinos and such.. That is why I like your channel.. you are a very good teacher.. even an old fart like me can follow what you are saying.. thank you I appreciate all of your hard work! Carry on!
@@tinkmarshino This rig was built in the mid 1980s, so about 35 years ago.
@@w2aew Wow.. that was a while back.. I was settle down then.. sure looks in great condition but then I look ok 32 years ago when I was 35 also.. with with a wife and a couple of babies.. you do great work son.. thanks!
Why Yours TS-940S has a one EEPROM memory chip ?
Hi Alan, Have looked for a repair shop for kenwood 940 do you offer repair service? If not could you recommend someone? Thanks
I'm sorry, I don't offer repair services. I used to recommend Cliff from AAVID in Texas, but I think he retired. If you have a somewhat local ham radio store, they might be able to recommend someone since they probably get asked a lot.
Lithium batteries. The only thing I dislike more than leaky capacitors.
I sympathize with the engineers a little bit on mobile radios, but in a radio like this, with all of the available space, I don’t see why they didn’t relocate those batteries to easier to get to locations, or even used spring loaded battery holders like you see on many PC boards.
The Batteries Capacity is what determines the batteries discharge rate of the speed of the current? The batteries current is "dissipating" each time you apply a load to the battery, the discharge rate of the current is determined on what?
I have a TS850s that seems to be out of frequency alignment. Something you can correct?
This is something that YOU can likely correct (assuming that it is just the frequency accuracy that is off). Here is a procedure I wrote many years ago:
www.qsl.net/w2aew/adjustrig.htm
Can somebody tell me what are those 2 components with 4 strips on 1:18 at the bottom center of the screen? Are those resistors or inductors? I pulled out few of those from old device, but resistence reading is ~0.5 ohm.
Plain simple power resistors. 0.5ohm is not unusual, you can get 0.01ohm resistors if you want. Their main use is current sensing (shunt).
@@mrnmrn1 I found them in PSU, as a fuse replacement.
Just put one in my 2m Yaesu. Not as bad as that. Did not use OEM.
is it possible to make a video about analog signal generators? once you showed one saying you made it many years ago. can we get a series like how to design, make analog function generator, or how you made yours, maybe a schematic walk through. I know today I can get an IC and use some precision opamps, but analog sounds more interesting :)
You have so many cool notes, way better than college lecture notes. Is there a way to have the notes you use on the videos available as pdf for us to use and download? That'd be super awesome! 73
Notes for most of my videos *are* available as PDF downloads already! If available, there is a link in the video description (you have to hit the "SHOW MORE" link...
w2aew, How do you measure the DC internal resistance of a 9 volt battery using what kind of meter? Carbon Zinc batteries have a higher DC internal Resistance compared to Alkaline batteries and Mercury Batteries which the DC internal Resistance puts a LOAD or changes the impedance of the power rails? its "adding" an additional resistances to the circuit?
The general method would be to measure the battery voltage with nothing connected, then connect a small resistor and measure the battery voltage again. You can calculate the internal resistance from these two values. To make it easy, adjust the resistor until the voltage is 1/2 of the open-circuit voltage. Then, the internal resistance is equal to the applied resistor.
9volt battery and adjust the resistor across the battery terminals until its 4.5 volts and that batterys DC internal resistance. This DC internal resistance is "in series" with the circuit which causes "loading" on the power rails and changes the impedance of the +Vcc?
Why does different battery types like alkaline batteries, carbon zinc, lithium, mercury batteries all have a different DC internal resistance value? What I mean is what is causes the DC internal resistance in battery is it the cells in series that creates the internal resistance in batteries?
Simple job hindered by a pile of loose cables :-) Is it just me (or the camera angle), or the positive terminal of the first battery behind the LCD display, at 4:30, is not completely soldered?
It's the camera and lighting angle - there is a good solder fillet all the way around the post.
@@w2aew I thought you wouldn't miss that, but after years of chasing cracked or cold joints, I became hyper-sensitive :-)
Thanks for answering!
Alan, hope you're well, haven't heard from you in a while.
Hello Alan!
I absolutely love your content, please keep up the good work, and greetings from Germany. :)
My guitar amp recently started picking up signals from a nearby cell tower. The tower just started to use 5G i believe, because the tower isn't new and i had no interference problems before.
Also the amp works just fine in a different room.
Do you have any tipps on how i could effectifly shield my amp or what i can do about it? Maybe this could be something for a new video? :)
Ferrite beads might help, see my video on that.
@@w2aew Thanks for the response!
I saw your video on that already. The interefence only occurs when i engage the build in reverb tank. The chinch cable already had a ferrit bead on it. I put a second one on it but the interference unfortunately is still present.
I noticed that when i lean over the amp in a certain way, the interference weakens. I guess my body then acts like a shield? Can i maybe get the same effect with some metal foil or so?
@@DavidRoyal1000 At this point, this type of experimentation and trial-and-error is the most effective way to address it.
w2aew Okay thanks! And again, please keep up the great content, I learned so much by watching your videos. Big thumbs up
@@DavidRoyal1000 have you tried more than one guitar?
Would you know where the battery is in a kenwood ts 870
It is very simple. It takes longer to remove the top and bottom covers then it takes to replace the battery. With the top and bottom covers removed, loosen the lower screws holding the front panel and remove the top two. Rotate the front panel down and the battery is right there. See page 81 of the manual located here: www.radiomanual.info/schemi/KENW_HF/TS-870S_serv.pdf You might not even have to rotate the panel...