How to spot a fault in a circuit, like a pro : hands on electronics [1]

In this video I show the method to find out a fault on an electronic circuit board. In the specific case we have an ESC (Electronic Speed Control) that is used to control a washing machine motor (used to drive the spindle of a lathe) and somewhere in the circuit there is a faulty contact. It turns out it was a bad soldering that caused an uncertain contact, making the motor to start and stop randomly. The video shows the procedure to spot the exact point where the fault is present.

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[thomastaylor]

I have never done this, I read several sites to find out how to do it, then I came here and learned 10x more than all the others in only 10 min so thank you!

[will_doherty]

Very nice demonstration of fault finding using schematics. I find that schematics are mostly very difficult to find for anyone outside of the industry, so I have to use different methodology - firstly check all electrolytic capacitors for signs of leakage/doming and replace any that have failed, then have a close look at the board - particularly components and soldered joints for signs of failure (under a microscope) - the fault that you had I would have found readily, and maybe in less time too. Next, look at power supply circuits and check that they're functioning as they should, and check all discrete semiconductors Then locate blocks of circuit that I recognise and test the components in each block. By this time most problems have been fixed. Checking the datasheets of unknown multi-pin ICs often comes up with sample circuits, many of which have been utilised by circuit designers - that makes some fault finding very straightforward. If after all this the fault remains and a schematic is not available, it's probably time to invest in a replacement pcb...

[jimmy_jamesjams_a_lot]

Very nice chuck fixture on that lathe. My main hobbies have migrated from EE over to Mechanics recently. I had never believed myself to be an innovator until I finally began with a few diy opportunities in recent times. I am saddened by the lack of instructions included with test equipments recently. So I am grateful for troubleshooting demonstrations such as yours. Accolades, and I wish you luck with your lathe!

[d.e.c]

This is the very first step (in) troubleshooting. Great job! We don't have (time) to

[brettkaufman]

Thank you for the education. It is nice to see the trouble shooting approach. Nicely done.

[theatremad]

Great video. Thanks for providing valuable information. This is worth much more than money. Knowledge is something you can’t put a price on. Thankyou

[dporrasxtremeLS]

Yes! This Takes the mystery out of the equation! Thanks!!!

[neodiy]

How do you always get access to the schematic diagram of the circuit...there is serious difficulty to find for certain specific devices

[consolechips]

You missed another dry joint above the broken pad you found … look at 12:14 on the top right it has cracks all the way around the pad.

[katiefinnegan]

I was so invested in this!!😆 well done

[brianlittle]

I like to use a plastic ink pen with the writing part of the pen retracted when I touch the board. The eraser part of a pencil also works. Never touch it with my fingers.

[paulf]

Thanks for putting this video together 💯
Did you have much trouble sourcing the schematic diagram of the ESC circuit?

[WilliamSiansala-kt]

Is there any way to test signal without oscilloscope and a multimeter

[hobonickel]

I've been trying to learn about using dmm because recently had a bad hexfet on tennisball machine PCB.. that's how I found your awesome video. However, now I'm more interested in that spindle head on the lathe.. Is that a Taig 5c or did you diy the the spindle, bearings and housing? I'll have to look through your channel and see if there's more vids about the lathe. I'm trying also to decide which route to go with a home hobby lathe
and the Taig 5c spindle head is $600 ...that's a nice looking spindle/head and perfect for what I'm looking toward for making pool cues

update: ok nvrm, I found your video regarding the lathe ... luv it

[sloopycat]

Hi Accidental science & everyone I have washing machine with faded and disappeared lettering on the digital display control board PCB I think it's called, some letters are visible but not all, i think it has ribbon connectors, please can you help me so all the letters are visible again, thankyou in advance. Great video thankyou.

[MartinLDeLoach]

Those that don't know that triangle thing on diagram is called a op Amp, operation amplifier..

[dashley]

My 10.2 PowMr will harvest so Load is being met but battery is not being charge till about 1800 w. The PV input readout is an arbitrary .5 kw till about 1800 w PV input. No one has had a clue why so far. A replacement 6.2 kW PowMr works perfectly. So the issue is surely in the 10.2 unit. Issue existed at initial startup.

[plis]

is it possible to do the same thing but with an analogic tester?

[MECANICA_NA_GARAGEM]

Hello.
the electrical circuit you are using, in addition to the motors (why two?), is it from a washing machine?
What changes did you make? From the schematic drawing shown in the video, were the changes in the handwriting?
can help? I'm also building a mini lathe and wanted to use a similar motor.
but I'm having trouble controlling the rotation of it.
Thank you for your attention .
Cheers

I forgot.... congratulations
one more subscribed

[Necrozene]

Huh? You missed that on initial visual inspection? Oh dear. Great fun though, following your subsequent logic!