Mesa Hearbreaker Intermittent Volume Loss

[thunda]

My Heartbreaker head has an intermittent volume loss. Changing cables does nothing. Problem persists whether in 60 or 100 watt mode. Silicon or tube rectifier setting does not affect the problem. Problem is persistent in either channel. Suggestions? Change PI tube? Clean all pots and jacks with contact cleaner? I do not think V1 affects both channels as each channel has two preamp tubes but am not sure. There are also preamp tubes for the effects loop and reverb.

any suggestions will be greatly appreciated.

ty

[soundguruman]

its usually dirty controls and jacks, old preamp tubes, or resolder the boards. For one, just put a set of preamp/power tubes in the thing.
when your pre out / power in jacks, or your effects loop jacks get dirty, it causes problems like this. The jacks have internal switches, that are intermittent due to crud and oxidization.
occasionally, you will need to replace the plastic switches, if there are any, like the 50/100 switch, triode pentode switch, etc...those plastic switches go bad and intermittent.
you know, there is some big resistors on the circuit board, that break loose or the solder connections fail.
and the tracks from those resistors might have burned...
you can usually get it going if you check those things.

[thunda]

thanks. I replaced the V1 tube and the problem cleared up but did not have the volume I was used to. I then noticed that one of the inner pair of power tubes was alternately getting brighter then dimmer. I replaced the inner pair and fired the amp up. Now one of the outer pair does not light up at all. i replaced that one with the "good" one from the inner pair and there it was: screaming glory. Looks like I need a new set of power tubes.

I appreciate the help.

ty

[R.G.]

The first step in servicing a tube amp is always to substitute in known-good tubes. Always. There is a reason they're in sockets.

Every smart tube amp owner has a set of ready-replacement, known-good tubes just waiting for when he needs them.