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YES! THANKS! I missed that. Pin 4 of LM358, as well as the 33Ω resistor connected to it in my diagram are both connected to the ground - to the negative of the large filtering capacitor 1000µF / 50V

I put the info in description under the video, when you click on "...more" Resistor 0.056 Ohm is 1W, part nr. 311-0.056TCT-ND from DigiKey

I'm not too sure. I haven't paid attention to that. It's an interesting question since the winding (5:14) appears to be divided into 12 sections - with 6 pairs of poles to interact with the rotor. I will check it at the next opportunity and post the findings.

I imagine that iGaging heard complaints about the lack of auto OFF which is pretty standard in all digital calipers. So they redesigned the circuitry around 2022 - assuming from the year printed on the new caliper's instruction sheet that includes the mention of auto OFF. But the one major screw up is that the new caliper loses its absolute memory after four days of rest. It makes me wonder who makes and who approves these terrible decisions?

That white stuff has rubbery texture but it is pretty dense, so you need to be patient, careful and persistent in removing it piece by piece. I used exacto knife to cut it up, and precision long nose pliers to remove it bit by bit. I also used a small pick hook to pry it. In the end I cleaned up the board with q-tip and rubbing alcohol. It will come off, but be extra careful not to damage the good components or the board when using tools. Good luck!

That resistor is 0.056, not 0.56 The two mosfets - if fried - will be likely shorted to zero Ohms between all 3 pins, which will show on the Ohmmeter without removing them from the board. The failing or failed fan would cause the overheating of the output modules, it will need a new fan of the same size and voltage. In my experience, the greatest challenge can be soldering without damage to the densely situated traces. Whoever does it needs to have good experience in PCB soldering. Good luck!

@@tektech1065 Thanks for the reply, Yes .056. I ordered the components on ebay. I just installed them and it still is not working correctly. If I only plug in the amp I repaired, it stays powered up until I shut it off. If I turn it back on it wont power up unless I unplug it for about 30 seconds. The amp that was good works fine by itself. If I install both amps, it trips the solid state circuit breaker. I tried both amps by themselves in both positions. No difference. Any ideas? Thanks, Bill

@@nancymccormick5809 Hello Bill. From what you described, it might be a failing electrolytic capacitor in the switched mode power supply. They can be tricky to diagnose if you don't have a ESR in-circuit tester. Look for small size high voltage caps. In the Service Manual, page 50 you will find the power supply diagram. I would leave the large 390 uF 200V caps (C804 and C808) in place and look to replace the smaller ones: C810, C814, and C819. You will find the Service Manual just by googling STAGEPAS 300 SERVICE MANUAL PDF Good luck!

Hi Albin! Most cheap calipers are made in China, so they are probably about the same sold in USA and in Europe. Digital Helios calipers are made in Germany, known for top quality, but not very common in USA. Japanese Mitutoyos are the gold standard in machine shops across the USA. One year out of CR2032 battery is a good life span if you use the caliper all the time, but not so good if it dies after one year in storage or after being used only once a week. These lithium batteries have the capacity of 200-225 mAh, less than 2% a year self-discharge rate, and a 10 years storage life. If the caliper draws a constant 21 µA current, then a 210 mAh battery would last 10000 hours, which is 417 days. But if the current goes to zero after I use it 4 hours each day, then the battery will last 6x longer = 2502 days, or almost 7 years. I use calipers for hobby, not too often, and so I like to have one in every toolbox and always ready.

Final schematic screenshot is at 12:00 The first schematic in the video was for testing. That's when I learned that I had to add the extra 750k resistor to the output, or the timer would never turn off. The back-to-back diodes isolate the blob while providing negative potential to one side of the reset/zero button to operate. It works great. But I would probably wire that part little differently next time. I would skip the top diode to the blob and leave an open trace there. And wire direct connection between the negative of the push button and the isolated negative of the battery. I will test the idea on my next caliper ;)

It's a little bit of "brain surgery" but works great when done. The timer works on 2-5V, and so any caliper with 3V lithium battery should be good for this project.

@@tektech1065 I have started. there is absolut no place for it. it's a alkaline model :( but I have a tiny tiny 3 legged switch. and tomorrow I will finish it. I have cut the board today. and tomorrow i will drimmel away metal. absolut not a job for a newbie. but 46 years of rutine. and it is gonna happen :)

It's a classic case of: "If it ain't broke, don't fix it."

The CD door with control buttons was meant to replaced and never repaired. However, that ribbon cable is extremely hard - if not impossible - to insert into the door socket if you get replacement door without that cable factory attached. But they are excellent players when they work.

On page 14 of the 62-page version of the Service Manual for CFD S350, you will find the procedures for mechanical and electrical adjustments. This Service Manual is available for download for free from elektrotanya - see the page address included in the video description. The bottom right corner of page #14 shows picture with the location of that adjustment: it's a tiny hole in the back of the motor. A small flat screwdriver will adjust the speed. It might not be possible to make the speed adjustment and listen to tape at the same time because you may have to disconnect the cables in order to gain access to the back of the motor. If that is the case, then make one tiny turn at a time (3-5 deg.) with screwdriver and reconnect all to listen to the tape. Turning the adj. counter-clock wise will most likely slow it down. Volcals make it easiest to detect the wrong pitch. Good luck!

@@tektech1065Thank you so much for this information. I tried to send you a message yesterday, but there was some kind of problem that wouldn’t allow me to post a big THANK YOU for all your help and advice. It finally dawned on me to go straight to the video and respond this way.😊

Good point! Analog quartz wrist watches use miniature version of the same Lavet stepping motor (Shown in this YT video: CXtOJYvaX-s). Speeding up the motor to create a sweeping continuous movement of the seconds would consume more power and deplete the battery a few times faster. In a wall clock, the manufacturer can remedy the problem by simply using a larger battery: C or D size. But a wrist watch has limited space for battery, so a ticking seconds hand is the best option. This could change in the future with some invention of equally small but more powerful watch batteries.

@@tektech1065 Thanks sir! I’m a chemical engineer working in a semiconductor industry. This motivates me to pursue a hobby into battery making😁😁 Cheers to you! 🙌

There are two reasons for doing that: 1. To save the battery from depletion, and 2. To prevent it from leaking inside the caliper. A mechanical switch solves problem #1. A lithium battery solves problem #2. But in case of LR44 or SR44 batteries (Mitutoyo calipers), I would buy them brand name, fresh, and always replace for a brand new every few years.

Amazing job! ruclips.net/video/Zi1KoiY7cv8/видео.html I will need to sit down and finish the planned retrofit of my broken Hakko 808. The quality of your video is so impressive! And you included every important detail of the replacement procedure. I will post your link wherever I see someone reporting broken heater in Hakko 808. Thanks, bro! And congratulations on the successful repair!

@@tektech1065 I posted the directions on how to calibrate the heater in my video, If you have one of those soldering iron tip thermometers, you can use that to calibrate the iron and not worry about the thermocoupler. The complete S-993A was only $100 USD, and it includes a nice stand, honestly, its not that bad. I really didnt want to destroy the Hakko in case an orig heating element pops up somewhere. I forgot to mention in my video, I used a Q-tip swab and put some Armorall on the two rubber diaphragms. Mine are 25 years old, if those were to break, I definitely will retire it.

@@n8vnewyawker8 Thank you v. much! I know Hakko recommends a temp. "calibration" but I don't see it possible to any degree of accuracy without any feedback from the heater. I think that's why the 808 are notorious for prematurely burned up heaters. Good point on getting the cheaper Chinese desolder tool. I just enjoy the challenge of fixing broken stuff whenever I have a chance.

Sure! Both amp modules are identical (and swappable). Can you see any markings, number etc., on the board? Could you compare the two modules and identify the corresponding markings on the other one?

Tek Tech I forgot to mention the suspect part is near 1604 on the Power amp module. I can't identify the blown part. Thanks for the help.

@@davemac01able-eu3nn Since I got no pictures of your amp, I can't help. Sorry. But you may get lots of really good practical help in electronics forums such as "badcaps forum" of "eevblog forum" where you can share the pics. You could also post link there to this video, so the guys would know what amp you talk about. Good luck!

@@tektech1065 Thank you for your advice on checking markings on board and checking with electronic forums.

Congratulations on your degree! Playing with the basic stuff I keep admiring the ingenuity of early electrical and electronics inventors. Anyos Jedlik is among the greatest with his original invention of an electric motor and then a dynamo.

Interesting! I don't see the code EAA at all on this particular controller's display. Let me ask: 1. Is your controller XY-WT04 or a different model? 2. Are you able to enter the settings function at all? 3. Does the beeping continue when the thermocouple is disconnected? 4. Could you short the thermocouple terminals with a piece of wire and see if the beeping continues on? In my controller the alarm can go on only in two situations: under temp. and over temp. But only when I set the alarm to go on, like at 3:22

Thank you! Would you perhaps post a video (even a short one) if it works for you? The Japanese pump in 808 is of top quality but the idea of having heater without a thermocouple to limit the temp. was a disaster. I will soon post a new video where I will retrofit my broken 808 with this Chinese heater and new tips from the S-993A and an actual proper temp. controller, the same as here: ruclips.net/video/Y8-SJ20jm8Y/видео.html

@@tektech1065 Thanks for the reply. Let me begin with a short synopsis... (not sure what happened but I replied earlier but it never posted) After noticing it wasnt heating up, I checked the element... no continuity, then plugged it in to check voltage to the heater w meter, none. I was assuming it was the rectifier/thyristor, AC03D or bad component on circuit board. At that point, I was contemplating the Hakko's last rites. Did a little more research on youtube and found this video first by KB1UIF which describes the circuit (I sold my scope a few years ago): ruclips.net/video/eniR4AkUo_c/видео.htmlsi=0PSvSLjVWcmeR3L1 Then I saw your video which confirmed the 993 element was a close fit (and omit the other 2 wires) and ordered the element and tips from Aliexpress. You mentioned about the temp runout sans thermocoupler... In the Hakko manual, it describes how to calibrate the iron with the two potentiometers. KB1UIF confirms the circuitry pulses the current to the element to control temps. When I receive the element, I'm going to try it out to see if it works. I will definitely be making a youtube video on this endeavor, and will give credit to both you and KB1UIF. If you can retrofit the thermocoupler into the Hakko, I will most likely do the same if this doesn't work and just keep it on the bench. Delivery of the element is going to be in a week or so. I will definitely keep you updated. Thanks once again. *** Forgot to also mention*** Was trying to figure out which connectors they used on the element so I didnt have to cut the orig off... I have a JST SM 2.54 female crimp that will accept the short male round pin (which I thought was molex but not).

If you use this power strip and hear the relay clicking, this means that the appliances plugged into any of the "Automatically Switched Outlets" would be switched ON and OFF with every click of the relay. This could damage the devices. The other types of "advanced" power strips do not have this problem at all.

O-rings are easier to get than specific rubber belts 👍

This fix should double its mileage 👍

All you can do is check it out. Good luck!

The battery connects to the printed circuit board via two steel springs which press against the board. You may try to take it apart again and clean the two contact pads on the board with Q-tip and Deoxit or rubbing alcohol. Look for signs of oxidation on the surface of the contact points - it's a common thing in quartz clocks. A more permanent fix would be an advanced "brain surgery" on the clock: tightly wind a piece of thin magnet wire around each spring and solder its end to the board. I showed it briefly in this video: ruclips.net/video/VGN-xoHSqTA/видео.html You could also just replace the mechanism but then the original hands may or may not fit. Good luck!

I don't know what exact size plug that was, just as long as it fits snugly on the pins of the LED. You can also just solder the wires to the LED. The current limiting 160 Ohm resistor in series can be connected to either one of the two wires. I found that the 5V regulator was the easiest component to tap power for the LED. And, of course, I needed another soldering iron to make those solder connections directly to the pins of that regulator.

Weller should know better

do you know at least what guage the wire was I think they are 2.54 jst plugs im trying to buy them on amazon im just going to wire strip the red positive twist on the resistor to that wire then solder the resistor after and use heat shrink is it 22 awg guage? I dont want to mess up the pcb

@@nikobobich9726 22 AWG is pretty thick, but it will work. I would use something extra small since the current is 20 mA or less.

Good question about the 0.5, or 1/2 Hz. The coil of the Lavet motor gets square wave AC like this: ⎍⎍⎍⎍. Every rise is one step of the motor equal to 1 second, and every fall is the next 1 second step. Therefore one full square wave cycle lasts 2 seconds = 0.5 Hz. That's the nature of the Lavet stepping motor - simple and genius. If the clock had a digital display HH:MM:SS then 1 Hz would be perfect to drive it.

This mod was intended for infrequent, occasional use of the tester and a safe long-term storage without the need to pull out the batteries or worry about self-dicharge. Carbon zinc batteries are not necessarily "low quality." They are preferred for low power equipment. For higher Amps you'd need alkaline. Some major brands (Maxell, Panasonic) keep manufacturing carbon zinc as well as alkaline batteries. In my experience, carbon zinc batteries don't leak as often and as badly as alkaline if forgotten and left for a longer time in remotes, etc. Rechargeable NiMH or lithium usually don't leak at all, when compared to alkaline. In this case, AAA NiMH rechargeables would work but they cost extra and self-discharge over time if you forget to keep recharging.

@@tektech1065 Nope, carbon zinc are low quality. They are cheaper to make and have less capacity, are only included for those two reasons. No "good" equipment includes carbon zinc instead of alkaline or rechargeables but if rechargeables then generally integrate a charging circuit. There is no harm posed by storing this with NiMH batteries which are so rare to leak that it is extremely uncommon from major brand cells. However I do recognize the problem with a device that has parasitic draw when it shouldn't in the most off state the user can set without removing the batteries. It is senseless that they would design it like that, merely to avoid a 2nd switch to latch on the power when the trigger or another button was pressed.

Apples and oranges.

Good idea! The little LED lamp is what I already had on my work bench. If I had a nice and bright lighted switch, that would be my first choice.

For the two outlets on the bottom to work you have to plug in and turn ON something (a lamp etc.) into the CONTROL outlet. Try that. The appliance you plug into the CONTROL outlet (top right) has to be 10 Watts or greater. If it's too small it will not turn ON the two bottom outlets.