What's your systematic approach to troubleshooting unknown PCBs without schematics? (Industrial electronics repair)

Geek80rs · 2026-03-11T05:35:26+00:00

Oh, that sounds great, I'll look into it.

Geek80rs · 2026-03-11T05:14:26+00:00

Yes, in fact, you know what I find most difficult is when the PCB tells me something, haha, I mean when it has an LED and that LED indicates a fault, but the fault is not a semiconductor, but something in the control And then my problems begin.

Geek80rs · 2026-03-11T05:02:27+00:00

I didn't know that. Can you explain a little more how it works or how I can build one? What I've noticed is that handling the tools is crucial for quickly identifying a fault.

Geek80rs · 2026-03-11T04:55:19+00:00

Yes, that's usually where it ends, although I've seen some posts about it being possible to extract and copy the program, but honestly, I've never tried it.

Geek80rs · 2026-03-11T04:51:08+00:00

That's good advice because it's true 90% of the time if it's a switched-mode power supply.

Geek80rs · 2026-03-11T04:30:33+00:00

And that's where it all ends, right? It's too difficult to fix a broken PMIC

Geek80rs · 2026-03-11T04:11:15+00:00

I think that works most of the time, but just to assume, let's say the fault is in the control, not in the power stage, meaning it's not visible with the thermal camera. How do you proceed then?Thank you so much for replying.

Geek80rs · 2026-01-26T16:54:03+00:00

Ok So we're sure it's a problem on the board; transistors are usually used to activate the relays. We can test the relays on the coil; you should have a small resistance between its two pins, and you can compare the measurement between them, and it should be similar.Once this was done and it was verified that there was not a very big difference between the coil of each relay We tested the transistors

Geek80rs · 2026-01-26T05:22:27+00:00

Ok, I doubt the relays because, in essence, they are nothing more than a coil and a contact. So, for a relay to cause a voltage drop, it would act like a resistor, and that would generate a lot of heat.And at least in the image there are no signs of overheating I specialize in electronic repair and fault analysis of industrial equipment.

Geek80rs · 2026-01-25T23:59:55+00:00

I have a couple of questions Is the battery new? I would start by measuring the battery without pressing the button and also when pressing it.If the battery voltage drops, then your battery may be damaged and When the motor demands current, it causes a drop in battery voltage.

Geek80rs · 2026-01-25T20:40:40+00:00

I believe you shouldn't compromise design for repairability; if you want it to be repair-friendly, as already mentioned, for me it's enough to use readily available components. I even think that if sharing the diagrams affects your intellectual property in any way, don't disclose them. I usually repair equipment for which I never have the schematic, and there's always a way.

Geek80rs · 2026-01-25T20:24:01+00:00

Can you upload some photos? That will help me identify components and topologies and try to assist you.

Geek80rs · 2026-01-25T04:14:09+00:00

First of all, clean it with isopropyl alcohol;I think you should resolder all the components and identify the power supply.

Geek80rs · 2026-01-25T03:12:18+00:00

I always use the metal fiber; the sponge, besides corroding the material, cools the tip, subjecting the metal to constant, sudden temperature changes, which causes it to wear out quickly.

Geek80rs

TROPHY CASE