Resistor

A diagram of where the resistor goes would be useful. If you're not sure, the question you should ask yourself is if a 10 cent part is worth killing your amp.

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>>1156552

Pic 1/2

Thats a close up of the spot it goes in. I'm replacing them because they caught on fire because of two shorted transistors.

Im not that worried of messing up the amp because it was going in the dumpster at my dad's business.

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>>1156552
Pic 2/2

Zoomed out pic

>>1156553
>>1156554
I'd definitely replace that with the correct resistor unless you like exploded traces.

>>1156556
So it is 1/4W? All the rest of the 1/2W resistors are labelled, so it kind of makes sense.

>>1156548
As long as the resistance is the same and the power handling isn't worse, it shouldn't make a difference. If either of those aren't the case, you'll run into problems.

That wattage rating is the maximum rating before it overheats putting in a higher wattage resistor shouldn't matter

>>1156556
Bullshit it is just about the maximum wattage which the resistor can handle increasing that number shouldn't effect anything

>>1156559
>>1156562
>>1156568
Thanks gents

Bump

I put everything together, and the same three resistors burned up again. I don't think the transistors shorted (I tested them and they seem ok).

Anything that tips you guys off that would cause this? I'm 99% sure that 560 Ohm resistor is the first one to light up, since it's the only one that has obvious signs of damage (the middle swelled up and it's all charred, meanwhile the two on either side of it seem fine on the outside, but no longer provide the proper resistance).

>>1156929
did you properly clean the pcb before replacing the components? those burns marks are essentially carbon which is conductive and might be causing a short
what about the underside of the pcb? any shorts/burned traces there?
did you check the remaining transistors on the board? its laborious (with all the removal and testing) but if the main driving transistors are fine, one of those small ones can be rated 1a or more and might be dead short and burning the resistors
gl

also, while you are at it, post a photo of the underside of the pcb, following the traces would make it easier to diagnose the issue (for all i know it might even be a dead/short diode, depending on the failure mode)

yes this is fine, it just means the resistor can resist double the amount of wattage than your previous one.. but it still resists the same amount of current

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>>1156940
Sorry for my late reply, I had no WiFi for a couple days.

Im in the process of mapping out the circuit on paper, just so I know what's connected to what.

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>>1156940
Top side of the board, same orientation

>>1156548
The resistor wattage rating is just the max. thermal limit.
A .5W resistor can "burn" .5W of power continuously without dying. Therefor a .25W R can always be replaced by a .5W R.
Why would you switch resistors at an amp, though?

>>1156929
Fixing blown amps is the biggest pain ever and needs a lot of experience.
Tried it sometimes and always gave up.
Even if you manage to replace all blown parts, you STILL have to set the correct bias current through the transistors where you would power the amp at a lower voltage to do that without damaging anything again.
If one amp channel is blown there are usually more damages than just the two transistors and two Rs. Follow the traces and test all parts on the way.
The amp in your pic is propably shitty so its not worth the trouble.

>>1158656
I'm kind of new to electronics, but not exactly. I thought it would be a simple fix at first but now that it's getting more complex I'm probably just gonna scrap the amp

>>1158654 is right, the wattage is just how much electricity you can put through the resistor before it burns up. As long as you replace it with the same value (same ohm) resistor there won't be any issues

Try to ohm out your driver transistors. Compare your readings from the failed side to the working side. You may have to remove the components from the circuit to confirm a failure.

>>1156578
I gotta be honest I love the strong bullshit replies at the start.


The one thing to be concerned about is why it blew. That was the weak link before for whatevere reason. Now you're putting in a stronger link you may find another part blows eventually. If you put in an identical part and the same fault existed you'd have the same failure tho.