Hey everyone,
I'm looking for some help on an amp i've been troubleshooting for a few months now.
I have a Peavey 5150 Mark II that is making intermittent crackles and pops.
Crackle is happening with old tubes and complete new set of power and preamp tubes.
The noise is in both channels.
If you remove V3 (effects tube) the crackling stops
Here's the schematic i'm working off of.
https://www.thetubestore.com/lib/the...-Schematic.pdf
I've been going down rabbit holes and nothing i've conducted has made the problem better or worse.
My next guess is a noisy coupling cap that's causing the issue but i'm shooting in the dark at this point.
Here is a list of the work I have done so far and why:
1) Replaced C34, C35, C38, C39, C44, and C46 filter caps. (Slightly bulging and they tested leaky)
2) Replaced R205 screen grid resistor (open)
3) Replaced C159, C9, C164, C163 electrolytics (caps blew)
4) Shotgun replaced all plate resistors on preamp board (I thought a noisy resistor was the issue - no change)
5) Replaced R5, C11, R26, R85, C158, R14 coming off V3A effects tube
6) Replaced all preamp tube sockets with new beltons. (contact pins on old sockets were in poor condition and couldn't be retensioned)
7) Bypassed the effects loop board completely to rule out any faulty resistors or transistors that may be on that board (no change)
Any help is appreciated.
thanks,
I'm looking for some help on an amp i've been troubleshooting for a few months now.
I have a Peavey 5150 Mark II that is making intermittent crackles and pops.
Crackle is happening with old tubes and complete new set of power and preamp tubes.
The noise is in both channels.
If you remove V3 (effects tube) the crackling stops
Here's the schematic i'm working off of.
https://www.thetubestore.com/lib/the...-Schematic.pdf
I've been going down rabbit holes and nothing i've conducted has made the problem better or worse.
My next guess is a noisy coupling cap that's causing the issue but i'm shooting in the dark at this point.
Here is a list of the work I have done so far and why:
1) Replaced C34, C35, C38, C39, C44, and C46 filter caps. (Slightly bulging and they tested leaky)
2) Replaced R205 screen grid resistor (open)
3) Replaced C159, C9, C164, C163 electrolytics (caps blew)
4) Shotgun replaced all plate resistors on preamp board (I thought a noisy resistor was the issue - no change)
5) Replaced R5, C11, R26, R85, C158, R14 coming off V3A effects tube
6) Replaced all preamp tube sockets with new beltons. (contact pins on old sockets were in poor condition and couldn't be retensioned)
7) Bypassed the effects loop board completely to rule out any faulty resistors or transistors that may be on that board (no change)
Any help is appreciated.
thanks,
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