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Learn How To Repair Electronics Without Schematics. Practical PCB Circuit Board Repair

Learn Electronics Repair

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Here is an interesting one. So a guy came into the workshop clutching a large PCB and asked me if I could fix it urgently So let's look at the process of undertaking this sort of repair, working out what the different sections of the PCB do and deciding which diagnostic method is most likely to result in a successful repair. Could you have fixed this PCB? Be honest with us all in the comments, and let us know if this video helped you or gave you more confidence with this sort of repair

I work in collaboration with:
The Electronics Channel (with Carlos and Detlef)
@theelectronicschannel

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Equipment used in my videos. These are affiliate links, you pay the normal price and I make a small commission.

DM40C
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Aneng AN870 (Same as Zoyi ZT219)
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Richard

20 Comments

@jplazas65 6 days ago

Thanks, Richard. I’ve only just come across these fascinating videos; there’s a lot to learn. Keep posting in Spanish. I am returning to this profession, which I had left behind 25 years ago; now, as I approach retirement, I am updating my skills and setting up a new laboratory as a hobby.

@learnelectronicsrepair Creator 2 years ago (edited)

Just to mention guys, I didn't have any high wattage resistors of the right value, so I used a couple of 51K and a 68K resistor in parallel (all 2W resistors) and this gave 17.5K which was close enough. The owner called me back the next day to say the aircon system was working perfectly. I think this is a large one which has four separate outlets (head units, whatever is the correct term) in different rooms

@katiefinnegan4649 2 years ago

I have thoroughly enjoyed this video. I'm revising and prepping for 2nd interview and needed a PCB refresher. Really good mate. Millions of thanks.

@Mcfreddo 2 years ago

Yes, I was glued to the end. Your videos are the best. I'm a novice and I very much appreciate your very good efforts.

@kennymanchester 2 years ago

These are among my very favorite videos, where true skill and troubleshooting skills are put to the test. Random electronic, PCB failures. I love it. Well done!

@brieftodo 2 years ago

HIC = hybrid integrated circuit. Love the channel!

@retrocomputinggrotto 2 years ago

Some people just want to know the fix so they can get on with it and that's fine if you already have a lot of experience and understanding, personally I think it is great to see different peoples fault-finding methods as this is a skill in itself. Thanks for another great video.

@Ascrappy1 2 years ago

I am impressed with your knowledge and use of logic and common sense. Your dad seams very knowledgable too! Your video’s have helped me a lot. Much appreciated.

@colinmackay852 2 years ago

You could also have used a small file or Dremel type tool to file one side of the resistor down.. you should be able to see where the resistor coil is broken/burnt and measure each side and deduce the value.

@orion4219 2 years ago

Love these type of videos and the comments.

@TerryDeSimone 2 years ago (edited)

* - Please show more IN-CIRCUIT testing... to help us diagnose without removing.. (if possible).. Also, VERY Good video.. Thank You...

@heroesandzeros7802 2 years ago

Keep in mind that environmental factors also come to play.
I once had an MOV that was mounted close to an 800 degree heat source and that temperature melts solder connections.
In this case, most of the solder dropped out of the 120VAC power connection and left the connection intermittent.
I wouldn't expect this board to be mounted that close to a high temperature source, but that resistor could have created it's own source.

@henrybartlett1986 2 years ago

Work is getting in the way of watching these wonderful videos!

@Salfke 2 years ago

Very nice teaching video, thank you

@mfx1 2 years ago

Looks unusually well designed and service friendly with all the silkscreen markings.

@USA-GreedyMenOfNoIntegrity 2 years ago

Fantastic. I appreciate you. I’m pro hvac, setting up electronics workbench to repair these, heat pump defrost control boards, gas furnace control boards and 3 ph dc and ac motor control modules….as they are very expensive ($300-1600USD) to replace. The only videos I can find require me to know Hindi although I’m trying to understand by watching their methods. Very similar to yours! If you get a chance to do more hvac stuff, jump on it. Take care.

@inseries5494 2 years ago (edited)

I figured it out before you :), based on electrolytic rating, the zinner should be around 50 V. Zener current should be around 10mA. now 230-50/10exp-3= 18kOhms!

@scroopynooperz9051 2 years ago

This is god tier stuff. If only my school teachers made it this interesting 😂 probably wouldn't have skipped class nearly as much or got in half the trouble lol

@BUTTEWORKS 2 years ago

Loving this videos, I'm learning lot of new things.

@CTCTraining1 2 years ago

Excellent video sharing your thinking as you go ... you might treat yourself to one of those grinding pens to help get past the board coating which is indeed a real pain. 😀👍