Squire bass guitar amp PB 15 no sound

[zzpkcq@gmail.com]

Looking for a schematic for this amp to help solve no output problem.
Power input ok no shorts, signal tracing for me is why I could do with a schematic.

thanks in advance

[CapLeaker]

Google finds nothing anymore. Staring to wonder why people still use it.

Anyway, here ya go!

[zzpkcq@gmail.com]

Thanks for the reply CapLeaker

But (there’s always a but) that schematic doesn’t seem right as it has less op-amps and more transistors than the bass version of this amp has. Another clue is this has a gain pot where the one I’m looking for has none.

tough ask I know that’s why I turned to BadCaps 👍

[CapLeaker]

Post some pictures of your amp and the boards so we can maybe find the correct schematic or something close. Maybe we don't need a schematic. It is just a little guitar amp, nothing too special. Just has a few op amps and a TDA something or other 15W brick. Common issues are broken input solder joints, cold solder joints in general everywhere. Blown primary winding on the transformer (no power), broken trim pots (I think last time I got them from Ali and they fit perfect).
I think it is based on the TDA2030.

[zzpkcq@gmail.com]

Some pics of the board to help identify it
Anyone suggest what to look at first.

I've satisfied myself transformer and rectified power is ok and can trace signal input from jack to first component.

I have multimeter, oscilloscope and bench power supply to help diagnose problems + can solder and unsolder components. So where to look first, schematic would help.

thanks in advance

[CapLeaker]

First make sure there is nothing in the headphone and the external speaker jack. If the contacts inside aren't up to snuff, there is no audio out. Try a set of headphones and see what you get. Clean those jacks with deoxid and ram a puff in and out all the the time. You can put your scope there to see if there is any audio. IC3 with that metal piece attached is your main amplifying IC. It should be a TDA2030. Make sure it gets power, input sound and output. Download the spec sheet and use your scope. If you have input and no output, the IC is bad,

I don't know what IC1 and IC4 is.The other three JRC 072D’s are op amps. If you got a negative voltage on the output, it’s bad, you should be seeing stuff on your scope.

[CapLeaker]

While I am unable to find the correct schematic, I did find something similar made by Fender. It will at least tell you how this thing works.

[CapLeaker]

Try this service manual from a Fender Frontman 15B (Bass). This looks awfully like your Squier BP-15. This should do.

[redwire]

OP what really helps is measuring the voltages on the IC pins (without slipping and shorting something out!).
If you can measure DCV with the multimeter (-) lead connected to ground, use the (+) probe write these readings down and post them here.

At this point, you could even have an open speaker....