Posssible to fix this burned PCB?

Thread Starter

GRNDPNDR

Joined Mar 1, 2012
545
First of all, this is a 600W electronic ballast that is garbage because of the burnout. I only want to try and fix this just to see if I can. Nothing important, just a fun skill testing exercise for myself and that's it.

That being said, is it possible to repair this damage and replace the resistor and get it working again?
It doesn't look like it's burned through the entire board, and I'm just about to check the other side after this post, but I thinking I could use a spot of epoxy to fix the "crater" and just drop in another resistor of the same value?

Attached are pictures of the damage, and a functional part. The entire board is covered in this rubbery grey stuff that picks off pretty easily....what is it?
IMG_9515[1].JPG

IMG_9516[1].JPG
 

Tonyr1084

Joined Sep 24, 2015
6,077
Before attempting to fix it you should first diagnose why it burned up like that. Simply replacing the resistor could result in yet another burn. I've seen resistors scorch boards before, that burn looks quite severe. I would guess that there is some other problem contributing to the problem.

Possible to fix? Hard to tell. Worth fixing? Unless it's rare and hard to replace, probably not. But none of us can tell without knowing more or without fully diagnosing the problem.
 

Thread Starter

GRNDPNDR

Joined Mar 1, 2012
545
Before attempting to fix it you should first diagnose why it burned up like that. Simply replacing the resistor could result in yet another burn. I've seen resistors scorch boards before, that burn looks quite severe. I would guess that there is some other problem contributing to the problem.

Possible to fix? Hard to tell. Worth fixing? Unless it's rare and hard to replace, probably not. But none of us can tell without knowing more or without fully diagnosing the problem.
Oh buddy, it's totally not worth fixing at all lol. like I said just a fun exercise to see if I CAN do it.

as for why it happened, I can only guess heat, and the fact that it's 9 years old and has been running in most likely stupid conditions. It's totally dusty inside.

Currently Im trying to get the board out of the housing because it's "glued" in with that rubber stuff along the slots where it would slide out. but this stuff isn't really holding on perse. might need a bit of percussive persuasion lol.
 

Thread Starter

GRNDPNDR

Joined Mar 1, 2012
545
If it's toast then so be it.

I think the hardest part would be finding the exact resistor.
I can't really determine if it's 3 brown or 3 black bands, so it's either 211ohm, or 2.11K ohm, 5 band, green (carbon film?)
 

Tonyr1084

Joined Sep 24, 2015
6,077
Looks like it has some kind of epoxy on top of the board. However, where the resistor burned the board - you may still have viable traces, but it's nearly impossible to tell. In the other board, the resistor color code may be better revealed if it were clearer and larger. Still, it burned for some reason. Possibly a shorted transistor or rectifier. Could be a bad cap too but - - - .
 

Thread Starter

GRNDPNDR

Joined Mar 1, 2012
545
it's like rubber, but just peels off and comes out in chunks cleanly.

yeah, it blew for some reason.... maybe that reason is heat, being covered in a layer of rubbery substance. Maybe that reason is bad design and a poorly chosen part, maybe it's a defective part, maybe this has been used and abused well beyond it's functional lifespan and outside of it's specs....who knows.

here's the rest of it. everything else in there looked good, bottom of the board nice and clean, no swollen caps, nothing looking out of the ordinary.

I'm not sure why we're fixating on this though when it doesn't matter at all.
 

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