I think we need to go back down the rabbit hole. I just got done with rebuilding a 930 I got off ebay for junk. Lord have mercy what a complicated nightmare. Digital board drove me crazy. Nothing worked on this monster. No display I tweaked L77 on the signal board to get it back on . That was the easiest part. Had a low 5 volt line bad caps and resistors behind the fan. It goes on and on....but you know it's really a super rig and I find myself getting attached to the ones I fix. Thank you Buddy for sharing your knoledge on these nightmares. 73
Did fix my TS940 with a pll unlocked by removing the wax! Now it is working well for 30-40 min and then suddenly loosing its rx audio, crackles,... then recovers. So probably a bad connection or soldering somewhere... But these sporadic issue are really hard to grasp! Thanks again for your inspiring videos!
After living with one of these for almost 2 years now, it seems to me that the key to resolving issues is knowing what does what. Mine had the dots below 2 MHz and the display goes berserk after about an hour. I started with the power supplies and backup batteries. Problems here will prevent everything from working properly. Adjusting L-24 on the PLL board one turn counterclockwise took care of the dots. I went through the board with a soldering iron and verified proper operation. What's left, acting possessed after an hour or so, comes down to the Digital A board, I believe. I have had everything from total loss of display after self-initiated auto tuner operation to the receiver continuing to function with no display or a locked display. Back in the day it was easy to fix 940s by module substitution, but finding a good anything for these is a crap shoot at best. The main problem is that the 940 is a really great radio when they work right.
Nice to watch a pro work Buddy! I got my venerable TS-940S new in 1986 and less a fix by Clif at AVVid and three sets of backup battery changes the rig has been operational. I learned long ago to keep detailed maintenance and mod notes on my gear (I'm kinda, well maybe a lot, OCD) and if I sell something to another ham the notes go along to give them the "history" as I hate second guessing someone else's work too! I'm sure you checked the batteries but just in case...can't wait for part 2! 73 - Dino KL0S
+Dino Papas That's good stuff Dino. Preventive maintenance is very important. Can save a lot of trouble down the road. Clif is probably the best I know on these radios. 73 my friend
Part of the problem is when they were designed and built. Like the short lived 930, the 940 was a first generation microprocessor controlled design that has fallen prey to time. When I searched for IC21 on the Digital A board I was surprised to find it in pinball machine repair depots. This device provides a positive reset of the primary CPU and the radio will not operate if bypassed. After recent work my 940 will operate normally for 65 minutes, then the display and buttons stop working but the radio will continue working.
+Beretta96Dan Thanks Dan. I have attempted to do a second part to this video. Put the radio on the bench, turned on the cam, and the radio went back to no display at all. Worked on it a bit got the display back then went out again. As soon as I can find the bad connection I plan to start part two of this series. Never seen a radio so hard to get along with lol. Like you said they are a bugger.
What is the serial number of this radio? Looking forward to Part 2!!!! You might want to include more detail on how you disassembled the radio to show what is involved. What method are you using to clean the connectors?
+DuffyF56 I will look at the serial, But I think it was an early unit. I have the video, just had to cut it down so it would not be so long. Thanks for watching.
the only reason I looking forward to a part 2 is I got a 940 it has about the same issue that you are having I got the wax of the PLL now just need to put it back in and test some of the voltages
+kc9kuh Ah I understand. So you are at the step of testing the VCO voltages. I am going to put mine back on the bench this week and go through those steps. Perhaps that will help you. I will also link in some documentation on my web site.
You got the patience of Job man. I never owned a new radio,or one that new, I got a sweet IC 751A. and it was 2nd hand,,, but I thought Kwood did better work than that. I have found it best to remove as much cold solder as possible , then reflow with silver or gold solder. Can you get a known good radio to look at and get back to Start? Or buy another and use this one for parts?
+darylynn621 One thing you will learn working on this stuff is patience. Specially one like this that has multiple problems. The 751 is a good rig. I have it's cousin the 745. Looks like I will be doing a video on it before long. The VCO trimmers are starting to go and causing 24 MHz and up to drop out. Also need to upgrade the ram board. Would be nice to have a working radio to do some board swaps, that would help narrow down the particular section that is bad. As soon as I can get more time I will fix this one. I found a few more issues that may be causing a lot of the problems.Thanks for your comments :)
The Radio Shop I was hoping to just replace the battery in the ram board. When I was searching for an LCD display for a no longer supported Kenwood portable. I found there was a lot to know,and there were lots of sources , Maybe your display is the same. My hobby is Cushman 's CE series, 3 and up. I collect and conserve them and accessories. I got my FCC 1st class at 17.pushin 63 now
Hi Buddy, great work so far. If the mods doesn't work, you must check all LO's individually. It is important to know which LO is freaking out and brings the PLL in unlock condition. Is the master ref available?? The caps in the charge pump are also always suspect.. 73
+TRXBench Hi Peter. Yep you are correct. LO is running fine. The problem is the rig has 6 PLL's and a few of them are not running. Could be due to several issues. more bad solder joints, wire connectors not making contact. It is a pain. This afternoon I came in to start checking PLL's again and now the display will not even come on. Arggg, got to love it. Thanks for the comments my friend.
Update...after resoldering, not merely reheating, all of the Digital A board pin connectors and all of the ICs plus the time base crystal the radio has been perfect for almost three hours now. If your radio doesn't have the dots but acts like it needs an exorcism break out a grounded tip iron and the magnifying glasses.
Working on the same issue, dots - resets work for days then goes dots. Resoldered both the digital and PLL - I guess next would be to scrap out the potting compound - I also reseated the rom
My dear sir I cannot thank you enough for such a clarifying informative video! I have exactly the same issues on my TS940SAT and am totally aware of the many problems that can develop over time. But, you actually gave me a direct view 'down the rabbit hole' to the PLL unit as I too have the same problem. Once the radio warms up comes the display but you can be half way through a qso and down it goes again, so frustrating. You hit it right on the head, we don't know what the previous guys have done!! So I will be now following in your footsteps to my PLL unit. Did you leave the plug 5 disconnected after the frequency displayed? Also I get the full output most times, but others it will intermittently shut down, 115 watts out one minute then no tx the next, carrier board likely culprit do you think? I succesfully repaired my TS430S by following a youtube repair video and its perfect still to this day. Your video is just what I needed, as I have a reasonable knowledge of seek and repair but I'm no guru. These are wonderful radios and the good thing is they can be repaired most times so I will stick with you on this repair just so as I can continue to enjoy using this TX. I will go through it all as you have and let you know what results. I have a problem with my sub display also it works but is not lit and I can see someone has had a whack at it but a little rough to say the least. This is what our hobby is all about a successful repair results in great satisfaction, great on air performance and thats what we want. I thank you again for taking the time to patiently teach us all you have learned, many thanks daryl vk2eat
Daryl, thank you for such kind words. It is very much appreciated. As you said these rigs are great, But when the inexperienced tech gets one on the bench is where a lot of new issues are planted. Like mine for example. Each time I go through it I find something new. This one is a basket case but I am determine to fix it. It sounds like you may have caught yours just in time. And the lack of TX could also be due to the PLL not sending correct information. Plug 5 is left off during some of the testing procedures to determine if it is the Main PLL or one of the other PLL circuits. I really feel like your tx is a result of missing pll voltages. As soon as I get some of my other projects nailed down I am going to attempt a complete check out video on my 940. Will most likely be broken down in many videos. Again appreciate your comments and thanks for watching. Plenty more to come.buddy kc4umo
+The Radio Shop No worries you're most welcome. My next look will be the poll unit who knows I might nail it. I'll make sure the solder connections are integral. Seeing them under your scope like that really drove the point home. I'll b keep in touch and let you know what I find best regards daryl
Thanks again Daryl. I am going to put a board under my new scope as soon as my camera comes in. Then we can really see the problems. Please do let us know what you find.
+Rick Gunther Hi Rick. At the moment with the work load at the public job I have only have one day a week to work in my shop. So as soon as things slow down a bit I will be back on this one. Should not be long. I have done some "off cam" work and finding other intermitted issues to track down. I promise to get back on it as soon as I can.
It would make your job so much easier and save the owner money in the long run if they didn't fiddle with things they have not got a clue about...1 word comes to mind Cowboys LORL. ....I did have a few choice words to say about them but toned it right down in case any younger viewers are reading the comments...Very best of luck getting it going...I would love to get my hands on a cheap none working one of these Transceivers....Regards from Steve Liverpool UK M0BFM
Right were you find the connector mod there is a voltage regulator I can't remember but is 18 or 19 volt is bolt into the aluminum wall that's the one y supply's voltage to the pll board re flush the pin and game over I fixed so far few ts940
+jjmtzama Correct, there is actually 3 regulators on that board. IC 6, 7, 8. All can give problems due to solder joints cracking. These radios needs lots of reflow :)
I DO HATE WORKING ON SOMEONES ELSES MESS!!! I used to be an Elect Tech for a local school system. The "guy" who had the job before me ( he was no Electronics Tech, he was ....... lets say a jack-leg) I could tell when he had been there. He would leave notes to himself. Funny part was , if he had just fixed right the first time he may not have had to come back.
all good Buddy. I did 2 kenwoods ts-440s did the diodes and caps all good dots are gone but i have another one and its a nightmare. keep up the good work from down under OZ
I had the dots a few years back on mine. Re soldered connections on the PLL board fixed it and still working. The boards were layered in there so took a little effort to get to it.
First thing I would do is remove every connector in that rig one at a time and clean it. Then reinstall. There are many of them and is a known issue with the problems these have.
Unfortunatly there were way too many issues in this rig from previous repairs. All the inductors had been removed from the PA board, lots of burnt traces on the main board.
I have a TS-940 that got hit by lightning 20 years ago and has been sitting out of service ever since. If memory serves the strike came in the power line and not the RF connector. When it powers up, I get that brief static sound followed by silence. I have a backlight on the S-meter, but no power at all to the main display or the sub-display. I'm hoping it's just a power supply problem. I'm trying to decide if after all this time it's worth opening up to fix. What do you think?
Really hard to say at least. I am sure there will be quite a few faults in the supply and main boards. Most of the time regulators short and sends high voltage everywhere. If you are interested in trying to fix it I am willing to help.
At this time no. There were several issue and equipment needed to finish this one up due to logic failures. This unit is full of IC's that need to be tested. And I needed a logic analyzer to continue. Also removing all the chips with my current desoldering system was a struggle. Even replacing all those tantalums was a chore for it. With in the last two weeks my old unit has been replaced by a Pace desoldering unit. Now just need the time to get back to it. Thanks for your question.
+DuffyF56 yes, the serial is 6060418. Have not gotten to part two yet. I am finding a few other issues I have to get cleared up. Someone did a few mods to the radio's supply rails. Just need more time to get to it. Thanks
Hello Paco. The fault is mainly in the PLL board. However this unit is not fixed. Seems several other folks worked on it and it has developed many more issues. As soon as I have time I will get back on it and do more troubleshooting. Thanks
I've got a Kenwood TS-140S that had the display go out. First it got dim then it went off completely but sometimes it comes back on bright then flickers on and off. Wonder where I should start looking, do you have any experience with that model?
+kc9kuh Been trying to get back on this one. Each time I get it on the bench another problem arises. This will be a very time consuming repair. Perhaps I will put it back on the bench today since wife is out of town. Thanks for the reminder.
What is the procedure to send a radio to you to go thru? I have a FT-101EE that works. I'd just like someone of your caliber to tidy up some things on it. Look me up on QRZCQ.com to see it if you want. Thanks and I really enjoy you sharing your knowledge with radios. 73, Mike/N8MLK
Hi. A quick question. I fixed a ft901dm I told you. I'm thinking about taking on a ft-102 for repairs or a kenwood ts-830s or other kenwood hybrid. Do you find the kenwoods better made and designed than the yaesu's? thank you.
Hi Doctor Forbin. I love each of the radios you mention,. Either of the two are great radios. The difference in the 102 and 830 is slim as far as build quality. I will say there is an issue that most are hesitant to tackle on the 830. There is a coil in the front end of the rig that is known to fail. That is L41. Older rigs like the 101 had a inline lamp that would absorb front end over load. The 830 does not have this so L41 often fails. It can be repaired. You can rewind the bobbin and get right back up and running. take a little practice. The 102 has an awesome receiver. Hard to beat. Down fall is the relays start to fail. But the rig has 3 6146 tubes for 150 watts out. Plus has AM operation while the Kenwoods do not. If you like CW then the Kenwood would be the better choice.. Again both are great rigs and will need TLC along the way to keep them running at top notch. You would not be disappointed with either. My choice....Both.
The doc seems to be better on the kenwoods. Any suggestion on where to get some really nice schematics on these radios? In advance thank you for your time.
thank you. the kenwoord schematics do not seem to be as large of a problem as the yaesu. I had a really hard time with schematics repairing the ft901. The ft-102 schematics I have found tend to be just as bad. any ideas?
Hello, 73 I wish someone could help. I have an equal radio does not work in TX in AM mode, but RX works well. Everything else works fine in all modes ..
The radio works well in SSB on TX / RX. It does not work in TX in AM mode, but works well in RX This radio was bought in Japan, it has the AC transformer for 100V Thanks
The radio did not work at first in the bands 18MHz and 24MHz and did not work in TX in AM mode. I made a change in the Digital board B (x54-1840-00)., cut the diode 130, to work on all bands. The radio worked in the bands 18MHz and 24MHz, but in AM mode did not work in TX.
Had some at one time. Lost many hours of footage on this rig during Mathew when my pc crashed. No time to get back on this one but I have a second one in for repair.
Hello Sr. I can see that you are a professional at the Kenwood TS-940S I have the same radio with the receiving and transmission problem, the batteries for the memory back up dead and my radio is unlock for 27, MHz. And I liked that way, I wonder about your shop location and if could get your phone number, I live in San Antonio, TX. I will appreciated if You send me back the information! Thank You very much, God bless. :-)
940 was a complicated rig...the 430 had same watts...you just need some Inrad filters...way easier to work on and 40 lbs lighter...Kenwood above all others.
Sorry but this radio was in too bad a shape to continue on. I found so many other issues on hacked boards under side and the PA has blown finals, resistors, and other parts. I al\m still looking for another unit to combined this one with.
I think we need to go back down the rabbit hole. I just got done with rebuilding a 930 I got off ebay for junk. Lord have mercy what a complicated nightmare. Digital board drove me crazy. Nothing worked on this monster. No display I tweaked L77 on the signal board to get it back on . That was the easiest part. Had a low 5 volt line bad caps and resistors behind the fan. It goes on and on....but you know it's really a super rig and I find myself getting attached to the ones I fix.
Thank you Buddy for sharing your knoledge on these nightmares.
73
Did fix my TS940 with a pll unlocked by removing the wax! Now it is working well for 30-40 min and then suddenly loosing its rx audio, crackles,... then recovers. So probably a bad connection or soldering somewhere... But these sporadic issue are really hard to grasp! Thanks again for your inspiring videos!
After living with one of these for almost 2 years now, it seems to me that the key to resolving issues is knowing what does what. Mine had the dots below 2 MHz and the display goes berserk after about an hour. I started with the power supplies and backup batteries. Problems here will prevent everything from working properly. Adjusting L-24 on the PLL board one turn counterclockwise took care of the dots. I went through the board with a soldering iron and verified proper operation. What's left, acting possessed after an hour or so, comes down to the Digital A board, I believe. I have had everything from total loss of display after self-initiated auto tuner operation to the receiver continuing to function with no display or a locked display. Back in the day it was easy to fix 940s by module substitution, but finding a good anything for these is a crap shoot at best. The main problem is that the 940 is a really great radio when they work right.
Thanks for sharing that. They can really be nice radios when working right. But can develop so many problems.
Nice to watch a pro work Buddy! I got my venerable TS-940S new in 1986 and less a fix by Clif at AVVid and three sets of backup battery changes the rig has been operational. I learned long ago to keep detailed maintenance and mod notes on my gear (I'm kinda, well maybe a lot, OCD) and if I sell something to another ham the notes go along to give them the "history" as I hate second guessing someone else's work too! I'm sure you checked the batteries but just in case...can't wait for part 2! 73 - Dino KL0S
+Dino Papas That's good stuff Dino. Preventive maintenance is very important. Can save a lot of trouble down the road. Clif is probably the best I know on these radios. 73 my friend
You have to be one hell of a detective to isolate the problem!!👍👍😎🇨🇱
Buddy Will be waiting for part 2 You are my Kenwood go to guy Thank You Will watch whatever you do
Great, I have two of these in the shop and both are in bad shape. Hope to get back on them soon. Thanks Wayne.
Your repair videos are useful and good ! Did you ever do a part 2 about the TS-940 display problem?
Thanks very much for the time and effort that you put into this channel. I've learned a lot just after watching two or three. Take care, Bob T.
Thanks Bob
Hope you manage to find the issue there, as you say it's definitely a rabbit hole. Looking forward to part 2.
Cheers
John
+orbiter8 (John) Thanks John. Yes it is a job going through all these wires and plus there are 6 PLL's in this rig
Part of the problem is when they were designed and built. Like the short lived 930, the 940 was a first generation microprocessor controlled design that has fallen prey to time. When I searched for IC21 on the Digital A board I was surprised to find it in pinball machine repair depots. This device provides a positive reset of the primary CPU and the radio will not operate if bypassed. After recent work my 940 will operate normally for 65 minutes, then the display and buttons stop working but the radio will continue working.
Thanks for sharing
Your explanation of the problems is clear and understandable! Great work! (PD0JGR) Holland.
Enjoyed the video, Buddy. I am now waiting for Part 2, 3, etc...Lol! Those 930's and 940's can be a bugger! I'll keep an eye out for part 2. 73...Dan
+Beretta96Dan Thanks Dan. I have attempted to do a second part to this video. Put the radio on the bench, turned on the cam, and the radio went back to no display at all. Worked on it a bit got the display back then went out again. As soon as I can find the bad connection I plan to start part two of this series. Never seen a radio so hard to get along with lol. Like you said they are a bugger.
did you ever make part 2 of this ?
Your repair videos are fantastic! Did you ever do a part 2 about the TS-940 display problem?
What is the serial number of this radio? Looking forward to Part 2!!!! You might want to include more detail on how you disassembled the radio to show what is involved. What method are you using to clean the connectors?
+DuffyF56 I will look at the serial, But I think it was an early unit. I have the video, just had to cut it down so it would not be so long. Thanks for watching.
the only reason I looking forward to a part 2 is I got a 940 it has about the same issue that you are having I got the wax of the PLL now just need to put it back in and test some of the voltages
+kc9kuh Ah I understand. So you are at the step of testing the VCO voltages. I am going to put mine back on the bench this week and go through those steps. Perhaps that will help you. I will also link in some documentation on my web site.
You got the patience of Job man. I never owned a new radio,or one that new, I got a sweet IC 751A. and it was 2nd hand,,, but I thought Kwood did better work than that. I have found it best to remove as much cold solder as possible , then reflow with silver or gold solder. Can you get a known good radio to look at and get back to Start? Or buy another and use this one for parts?
+darylynn621 One thing you will learn working on this stuff is patience. Specially one like this that has multiple problems. The 751 is a good rig. I have it's cousin the 745. Looks like I will be doing a video on it before long. The VCO trimmers are starting to go and causing 24 MHz and up to drop out. Also need to upgrade the ram board. Would be nice to have a working radio to do some board swaps, that would help narrow down the particular section that is bad. As soon as I can get more time I will fix this one. I found a few more issues that may be causing a lot of the problems.Thanks for your comments :)
The Radio Shop I was hoping to just replace the battery in the ram board. When I was searching for an LCD display for a no longer supported Kenwood portable. I found there was a lot to know,and there were lots of sources , Maybe your display is the same. My hobby is Cushman 's CE series, 3 and up. I collect and conserve them and accessories. I got my FCC 1st class at 17.pushin 63 now
Hi Buddy, great work so far. If the mods doesn't work, you must check all LO's individually. It is important to know which LO is freaking out and brings the PLL in unlock condition. Is the master ref available?? The caps in the charge pump are also always suspect.. 73
+TRXBench Hi Peter. Yep you are correct. LO is running fine. The problem is the rig has 6 PLL's and a few of them are not running. Could be due to several issues. more bad solder joints, wire connectors not making contact. It is a pain. This afternoon I came in to start checking PLL's again and now the display will not even come on. Arggg, got to love it. Thanks for the comments my friend.
very interesting...we will be waiting for part 2
Thanks and stick with me. This is a tough one. So much I found wrong in this radio. Will get back to it though.
Update...after resoldering, not merely reheating, all of the Digital A board pin connectors and all of the ICs plus the time base crystal the radio has been perfect for almost three hours now. If your radio doesn't have the dots but acts like it needs an exorcism break out a grounded tip iron and the magnifying glasses.
Great tip!
Working on the same issue, dots - resets work for days then goes dots. Resoldered both the digital and PLL - I guess next would be to scrap out the potting compound - I also reseated the rom
Yep I would remove that potting compound and make sure the foam under the PLL is removed. So many issues that cause the dots on these things
My dear sir I cannot thank you enough for such a clarifying informative video! I have exactly the same issues on my TS940SAT and am totally aware of the many problems that can develop over time. But, you actually gave me a direct view 'down the rabbit hole' to the PLL unit as I too have the same problem. Once the radio warms up comes the display but you can be half way through a qso and down it goes again, so frustrating. You hit it right on the head, we don't know what the previous guys have done!! So I will be now following in your footsteps to my PLL unit. Did you leave the plug 5 disconnected after the frequency displayed?
Also I get the full output most times, but others it will intermittently shut down, 115 watts out one minute then no tx the next, carrier board likely culprit do you think? I succesfully repaired my TS430S by following a youtube repair video and its perfect still to this day. Your video is just what I needed, as I have a reasonable knowledge of seek and repair but I'm no guru.
These are wonderful radios and the good thing is they can be repaired most times so I will stick with you on this repair just so as I can continue to enjoy using this TX.
I will go through it all as you have and let you know what results.
I have a problem with my sub display also it works but is not lit and I can see someone has had a whack at it but a little rough to say the least.
This is what our hobby is all about a successful repair results in great satisfaction, great on air performance and thats what we want. I thank you again for taking the time to patiently teach us all you have learned, many thanks daryl vk2eat
Daryl, thank you for such kind words. It is very much appreciated. As you said these rigs are great, But when the inexperienced tech gets one on the bench is where a lot of new issues are planted. Like mine for example. Each time I go through it I find something new. This one is a basket case but I am determine to fix it. It sounds like you may have caught yours just in time. And the lack of TX could also be due to the PLL not sending correct information. Plug 5 is left off during some of the testing procedures to determine if it is the Main PLL or one of the other PLL circuits. I really feel like your tx is a result of missing pll voltages. As soon as I get some of my other projects nailed down I am going to attempt a complete check out video on my 940. Will most likely be broken down in many videos. Again appreciate your comments and thanks for watching. Plenty more to come.buddy kc4umo
+The Radio Shop No worries you're most welcome. My next look will be the poll unit who knows I might nail it. I'll make sure the solder connections are integral. Seeing them under your scope like that really drove the point home. I'll b keep in touch and let you know what I find best regards daryl
Thanks again Daryl. I am going to put a board under my new scope as soon as my camera comes in. Then we can really see the problems. Please do let us know what you find.
my kenwood 940s has the same problem in part 1 when will part 2 be posted?
+Rick Gunther Hi Rick. At the moment with the work load at the public job I have only have one day a week to work in my shop. So as soon as things slow down a bit I will be back on this one. Should not be long. I have done some "off cam" work and finding other intermitted issues to track down. I promise to get back on it as soon as I can.
These seem to be a nightmare. From what I’ve been reading they sound like they were trouble when new.
Agreed!
Kenwood TS-940S did you do part 2 yet thanks
Nope, no part two on this one. There were just too many issues once I went further into it. Most of the PA section was burnt up and bad solder traces.
part 2 ?
did you ever finish the radio?
Very good .. a waiting for part 2.
Best Regards
Jose M
CE 3 LQH
I have a second one of these now I will be working through also. Same issues.
Interesting ... waiting.
73s & good luck
+José M. P. Me too
I'll be waiting for it. 73 to you!!
Thanks
This same problem have, PLL board and uPC board
checked and still nothing. EEPROM on uPC boardhas lost program?
I guess Part 2 was cancelled due to radio being beyond repair :-) Looked pretty nasty with all of the connectors cuts and soldered-back haphazardly.
It is in pretty bad shape. The more I worked on it the more problems came about. Not sure what I am going to do yet.
Mine has low modulation on AM. Im.told I sound off frequency. SSB sounds great. Any ideas?
by the way great job on showing the problems
+Rick Gunther Thank you very much Rick
Still have You got this Kenwood?
It would make your job so much easier and save the owner money in the long run if they didn't fiddle with things they have not got a clue about...1 word comes to mind Cowboys LORL. ....I did have a few choice words to say about them but toned it right down in case any younger viewers are reading the comments...Very best of luck getting it going...I would love to get my hands on a cheap none working one of these Transceivers....Regards from Steve Liverpool UK M0BFM
forgot to mention subscribed now waiting for part 2.....Cheers
Yes I see that all the time Steve. Some folks do not stick to the original plan. But it makes for an interesting repair lol.
Thanks for the sub. Will try and get back on this as soon as I can,.
Right were you find the connector mod there is a voltage regulator I can't remember but is 18 or 19 volt is bolt into the aluminum wall that's the one y supply's voltage to the pll board re flush the pin and game over I fixed so far few ts940
+jjmtzama Correct, there is actually 3 regulators on that board. IC 6, 7, 8. All can give problems due to solder joints cracking. These radios needs lots of reflow :)
I DO HATE WORKING ON SOMEONES ELSES MESS!!! I used to be an Elect Tech for a local school system. The "guy" who had the job before me ( he was no Electronics Tech, he was ....... lets say a jack-leg) I could tell when he had been there. He would leave notes to himself. Funny part was , if he had just fixed right the first time he may not have had to come back.
I agree, at times you can find some interesting repairs. Thanks for sharing that story.
Did you do part 2 Buddy.
No sorry. This rig was in bad shape.
all good Buddy. I did 2 kenwoods ts-440s did the diodes and caps all good dots are gone but i have another one and its a nightmare. keep up the good work from down under OZ
I had the dots a few years back on mine. Re soldered connections on the PLL board fixed it and still working. The boards were layered in there so took a little effort to get to it.
Most of the ones I worked on only needed solder re-flow. This one is a dog!
i just acquired one of these and the read out stays at 14.000.00 and low revive and transmit need help
First thing I would do is remove every connector in that rig one at a time and clean it. Then reinstall. There are many of them and is a known issue with the problems these have.
I would have checked the 3 volt battery first, then alignment of PLL board.
Good job so far.
+Grant Fullen Thanks Grant :)
did i miss part 2? or is she a parts radio?
Unfortunatly there were way too many issues in this rig from previous repairs. All the inductors had been removed from the PA board, lots of burnt traces on the main board.
@@TheRadioShop thanks..
como ficou a finalização desse rádio tenho um do meu uso que esta com o mesmo defeito já quebrei cabeça mas vai ter que trocar a unit pll ok
How about fixing the radio and pt2 have the same problem here and cant seem to find the issue
at 17:35 connector left on a angle
Золотые руки!
I have a TS-940 that got hit by lightning 20 years ago and has been sitting out of service ever since. If memory serves the strike came in the power line and not the RF connector. When it powers up, I get that brief static sound followed by silence. I have a backlight on the S-meter, but no power at all to the main display or the sub-display. I'm hoping it's just a power supply problem. I'm trying to decide if after all this time it's worth opening up to fix. What do you think?
Really hard to say at least. I am sure there will be quite a few faults in the supply and main boards. Most of the time regulators short and sends high voltage everywhere. If you are interested in trying to fix it I am willing to help.
+The Radio Shop Thanks. I'm rebuilding my lab currently. Once I tear it open, I may be asking for help.
was there ever a part 2 to this?
At this time no. There were several issue and equipment needed to finish this one up due to logic failures. This unit is full of IC's that need to be tested. And I needed a logic analyzer to continue. Also removing all the chips with my current desoldering system was a struggle. Even replacing all those tantalums was a chore for it. With in the last two weeks my old unit has been replaced by a Pace desoldering unit. Now just need the time to get back to it. Thanks for your question.
Did you ever check the serial number? I don't see Part 2 unless I am missing something.
+DuffyF56 yes, the serial is 6060418. Have not gotten to part two yet. I am finding a few other issues I have to get cleared up. Someone did a few mods to the radio's supply rails. Just need more time to get to it. Thanks
dear ham
And as I fix it?
Where was the fault?
Thank you
Paco EA5GU
Hello Paco. The fault is mainly in the PLL board. However this unit is not fixed. Seems several other folks worked on it and it has developed many more issues. As soon as I have time I will get back on it and do more troubleshooting. Thanks
where’s part 2
I've got a Kenwood TS-140S that had the display go out. First it got dim then it went off completely but sometimes it comes back on bright then flickers on and off. Wonder where I should start looking, do you have any experience with that model?
Sounds like an intermitted issue. Start by reflowing solder on the display board.
Yep, display board sounds like the obvious place to look first.
part 2 ?
+kc9kuh Been trying to get back on this one. Each time I get it on the bench another problem arises. This will be a very time consuming repair. Perhaps I will put it back on the bench today since wife is out of town. Thanks for the reminder.
Where is part 2 of this?
Well with all the problems with this unit and little time, It will get here one day I hope. I have a shop full of these.
What is the procedure to send a radio to you to go thru? I have a FT-101EE that works. I'd just like someone of your caliber to tidy up some things on it. Look me up on QRZCQ.com to see it if you want. Thanks and I really enjoy you sharing your knowledge with radios. 73, Mike/N8MLK
Hi. A quick question. I fixed a ft901dm I told you. I'm thinking about taking on a ft-102 for repairs or a kenwood ts-830s or other kenwood hybrid. Do you find the kenwoods better made and designed than the yaesu's?
thank you.
Hi Doctor Forbin. I love each of the radios you mention,. Either of the two are great radios. The difference in the 102 and 830 is slim as far as build quality. I will say there is an issue that most are hesitant to tackle on the 830. There is a coil in the front end of the rig that is known to fail. That is L41. Older rigs like the 101 had a inline lamp that would absorb front end over load. The 830 does not have this so L41 often fails. It can be repaired. You can rewind the bobbin and get right back up and running. take a little practice. The 102 has an awesome receiver. Hard to beat. Down fall is the relays start to fail. But the rig has 3 6146 tubes for 150 watts out. Plus has AM operation while the Kenwoods do not. If you like CW then the Kenwood would be the better choice.. Again both are great rigs and will need TLC along the way to keep them running at top notch. You would not be disappointed with either. My choice....Both.
The doc seems to be better on the kenwoods. Any suggestion on where to get some really nice schematics on these radios?
In advance thank you for your time.
The best is keep checking ebay for an original service manual. They come up. But the 830 look in the link below:
www.n6wk.com/kenwood/TS-830S-Service-High%20Resolution.pdf
thank you. the kenwoord schematics do not seem to be as large of a problem as the yaesu. I had a really hard time with schematics repairing the ft901. The ft-102 schematics I have found tend to be just as bad.
any ideas?
Hello, 73
I wish someone could help.
I have an equal radio does not work in TX in AM mode, but RX works well.
Everything else works fine in all modes ..
Does ssb work in transmit?
Very interesting issue. May not be hard to track down. Give me some time I will look over the manual and see if I can help.
The radio works well in SSB on TX / RX.
It does not work in TX in AM mode, but works well in RX
This radio was bought in Japan, it has the AC transformer for 100V
Thanks
The radio did not work at first in the bands 18MHz and 24MHz and did not work in TX in AM mode.
I made a change in the Digital board B (x54-1840-00)., cut the diode 130, to work on all bands.
The radio worked in the bands 18MHz and 24MHz, but in AM mode did not work in TX.
Mate !!!!, You're an Amazing Doctor of Radio, I'm Speechless, If You Need an Elder Brother?, I'm Available :-)
Any updates?
Had some at one time. Lost many hours of footage on this rig during Mathew when my pc crashed. No time to get back on this one but I have a second one in for repair.
Hello Sr. I can see that you are a professional at the Kenwood TS-940S I have the same radio with the receiving and transmission problem, the batteries for the memory back up dead and my radio is unlock for
27, MHz. And I liked that way, I wonder about your shop location and if could get your phone number, I live in San Antonio, TX. I will appreciated if You send me back the information! Thank You very much, God bless. :-)
wayala43@yahoo.com
940 was a complicated rig...the 430 had same watts...you just need some Inrad filters...way easier to work on and 40 lbs lighter...Kenwood above all others.
vco problem
nice
Thanks
Hi, where is part 2?
Sorry but this radio was in too bad a shape to continue on. I found so many other issues on hacked boards under side and the PA has blown finals, resistors, and other parts. I al\m still looking for another unit to combined this one with.