half marshall 100 watt cutting out

[tweedydum]

hi,
a friend is bringing over his marshall stack tomorrow. Apparently, it has gone to half volume at least once. He thinks the tubes stop glowing when this occurs.

I thought I would start by chopsticking all board/tube/output txfm connections and hope that something is loose.

Any other suggestions?

thanks,
Dave

[dobbhill]

clean/re-tension sockets...
D

[Structo]

In a tube amp the first suspects should always be the tubes.

How long since he replaced the power tubes?

Since you mention half power, check the power tubes.
They have a finite life span.

The V2 tube gets hammered pretty hard in Marshalls as well.

So always check the tubes first. Take a known good tube and substitute it for each preamp tube.

If that doesn't fix it, then on to the power tubes.

[selloutrr]

i've had this a few times both were preamp related.