Rumble 25 V3

[pnut5150]

I have a Fender Rumble 25 V3, it works great until you turn the bass up with the volume up, hit a certain note and power stays on but looses all sound. Anybody have a schematic/service manual? I know these are notorious amps for issues.

[g1]

Fender does.
http://www.fmicassets.com/Damroot/Or...s-Diagrams.pdf

[pnut5150]

Thanks!! I called Fender they said they don’t give out schematics

[Jazz P Bass]

Did you try clicking on G1's link?
http://www.fmicassets.com/Damroot/Or...s-Diagrams.pdf
That IS the schematic.

Try the same conditions that cause the fault, but use headphones .
If it does not act up, then you may have a HP jack issue.

[pnut5150]

I did use his link 😊
Does same thing with headphones, I did forget to mention that you can turn it off and back on and it’s back to normal until you hit a hard note

[The Dude]

My bet would be a cold solder joint or a connection issue. Try "chopsticking" around and see if you can find a sensitive area.

[pnut5150]

I’ve reflowed just about the whole preamp board, I’ll keep searching..none of the test point voltages are reading correct

[g1]

How about if you try running something into the aux in? At least you can narrow it down a bit.

[Enzo]

Or maybe it is launching into oscillation.

[pnut5150]

I’ll try that

[pnut5150]

I have a scope Enzo, I’ve injected a signal into it, but I’m learning how to use the scope not real good at it. Any suggestions to try with scope or insights?

[pnut5150]

Same thing with phone thru aux G1, clips out and will work when powered off and back on until you crank the volume

[g1]

Maybe try disconnecting the speaker and see if it still cuts out with headphones.

[pnut5150]

Same thing with Speaker unhooked

[pnut5150]

Same thing with Speaker unhooked