Marshall tube amp. problem

[Basil]

Hello all
I have a Marshall 50 watt tube amp. that starts to
motorboat when the gain is turned up. Looking
for suggestions on what to look for.
tia Basil

 

[exray]

Basil wrote:

Hello all
I have a Marshall 50 watt tube amp. that starts to
motorboat when the gain is turned up. Looking
for suggestions on what to look for.
tia Basil

Bad paper caps? Have they been replaced yet?
-Bill M

 

[Basil]

Thanks Bill
All the caps. are polyester and the 3 electrolytics. I did
replace the
power supply cap. no help.
Basil
"exray" <dontspammeexray@coqui.net> wrote in message
news:108ah07f6au1o52@corp.supernews.com...

Basil wrote:
Hello all
I have a Marshall 50 watt tube amp. that starts to
motorboat when the gain is turned up. Looking
for suggestions on what to look for.
tia Basil



Bad paper caps? Have they been replaced yet?
-Bill M

 

[Merlin Zener]

On Tue, 20 Apr 2004 19:08:00 +0000, Basil wrote:

Basil wrote:
Hello all
I have a Marshall 50 watt tube amp. that starts to motorboat when the
gain is turned up. Looking for suggestions on what to look for.
tia Basil

Has it been years in a dusty/smoky environment?
A thorough cleaning - especially around the valve sockets might help.

 

[Basil]

"Merlin Zener" <merlin@localhost.localdomain> wrote in
message
newsan.2004.04.20.20.26.16.276485@localhost.localdomain...

On Tue, 20 Apr 2004 19:08:00 +0000, Basil wrote:


Basil wrote:
Hello all
I have a Marshall 50 watt tube amp. that starts to
motorboat when the
gain is turned up. Looking for suggestions on what
to look for.
tia Basil



Has it been years in a dusty/smoky environment?
A thorough cleaning - especially around the valve sockets
might help.

I will check on that Merlin thanks.
I think this was a back up amp that was in use so SMOKY? but
now days
not as much but its old 1986 or so.
Basil