Fender Rumble 150 cutting out

[nosaj]

I've got a fender Rumble 15 that is cutting out after playing it for a bit. Sometimes flicking the power switch will bring back the volume. I've looked over the board and do not see any burn marks or anything of the sort. Its a different kind of output being the Icepower 50asx2 than i'm accustomed to. Any suggestions besides just replacing the package?

Thanks,
nosaj

[g1]

Is the icepower module still getting input when the sound cuts out?
If not, replacing the module won't get you anywhere. Could be something as simple as iffy solder on P103 aux. power back to preamp.
Enable line from headphones good?

[nosaj]

Not sure if this will answer your question as i wont be able to look again till tomorrow. But when it cuts out not working from the speaker. The line out and the headphones still work.

I'll check power tomorrow.
nosaj

[g1]

Still a bunch of stuff between line out and input of the ice module.
And sounds like an intermittent, does tapping on the module do anything when it cuts out, or only cycling the power helps?

[nosaj]

Chopsticking reveals nothing. Still have signal at pin1 on the icepowerboard. 24v rails still there. enable pin .088vDC whether headphone plugged in or not.
I will check voltage at r38 and test c68. So it looks like it is muting the power amp.
nosaj

[g1]

It looks like the 5V enable must come from the ice module itself. So you may have to remove Q9 to see if it comes up.

[nosaj]

Removed q9 no dice. But I did see this (in pic). Looks like i should check for signal on U7 and after when i can make it quit.. I have to say I've seen the green stuff before but not like the diodes.
nosaj

[nosaj]

Got signal at r105 and no signal at r119. So I'll pull board and clean it up and see what happens.
nosaj

[nosaj]

When removing the components to clean up the board one of the diode legs broke . And the q9 disappeared off the bench. So when the 1n4448s and 2n7000 come in I'll report back. When you think you have a good variety of parts onhand and its not all there.
nosaj

[The Dude]

Be sure to tell the owner to stop setting drinks on top of his amp.

[nosaj]

You know there are no vents on top of the amp just the 4 screws to hold the chassis to the cab. So I'm not sure what it is or where it came from.
nosaj

[nosaj]

Replaced the 2 diodes and the transistors. Still same nothing. i am still getting signal to the input of the Icepower board. But the 5v on the P102 pin1 goes from .04Vdc to 1Vdc when headphones are inserted an removed.?
So based on that I would say the problem lies on the ice power module Or does the 5v not come from the icepower? I'm just not sure.
nosaj
icepower info attached

[nosaj]

Ok R38 15.86v in. no headphone .284Vdc .. plug in headphone 7.93Vdc.
At Q9
Headphone out Source 0.00 Gate .284vdc Drain .248Vdc
Headphone in Source 0.00 Gate 7.93Vdc Drain 0.00.
What am I missing here? not sure how to test the mosfet but i have 9 more

nosaj

[g1]

Yes, the 5V enable comes from the ICE module itself.
Disconnect C68 and R97. See if the 5V comes up at P102 'enable' pin. If it doesn't come up, the ice module must be bad.
If the 5V is now present, either C68 or Q9 must be bad.

[nosaj]

Would disconnecting p102 an checking the enable pin accomplish the same thing?
nosaj