Mesa 2ch Recto no signal through input.

[Redline]

She was playing great and sounding killer. Then today I plug in and nothing. I tried one of my other amps through this same setup and everything was fine. I changed the preamp tubes and still nothing through the input. The input jack solder looks fine and the wires are still soldered to the board. Any ideas?

[Chuck H]

Is there any sound from the speaker at all? Hiss, hum, etc. even a small amount. You may need to turn up the master volume to hear it well. If there is sound from the amp, do the tone controls affect it in any way? If not, if the amp has an effects loop try plugging directly into it. Any sound?

[Redline]

There is hiss coming through the cab that increases when the volume pot is turned up. I plugged in through the effects loop and still no signal.

[g1]

That would mean you have 2 separate issues.
But it's more likely you don't have the loop enabled when plugging into the return.

[Redline]

No the loop was on and level turned up.

[g1]

And could you hear hiss?
Which exact recto-verb is this?

[Jazz P Bass]

As much as I would like to say "it's so & so part", that ain't gonna happen.

At turn on, anything can fail.

A few key power supply voltage measurements would help narrow down the issue.

[Redline]

And could you hear hiss?
Which exact recto-verb is this?

Not a Rectoverb. It's an early 2 channel Dual Rectifier black face/ chrome chassis.

[Redline]

As much as I would like to say "it's so & so part", that ain't gonna happen.

At turn on, anything can fail.

A few key power supply voltage measurements would help narrow down the issue.

Don't really know where to measure those.

[g1]

Ok, so it's not a recto
Here's where I'm confused. If the volume can control the hiss level, which you can hear, then the noise is getting through the loop ok. If the loop can pass the hiss, you should be able to plug your guitar into the return and get sound.
Do you have another amp that you can connect the other amp's send to the boogie return?

This is hopefully the correct schematic:

[Chuck H]

If the volume knob affects the hiss that may mean that the amp is working fine from the volume knob forward. Of course I don't know which "volume" knob you're referring to.?. I think that amp has several. At any rate, if it's a channel master volume then signal seems to be getting through the effects loop ok. If it's the effects master then there still may be a problem with the loop. Which might explain why no signal was present when you plugged into it. Please tell us which volume and tone controls affect the sound you can hear at the speakers. Start with all volume controls up then listen as you back each one down and report on exactly which knobs effected what and how.

P.S. This may sound dumb (I certainly felt that way) but if that amp is equipped with a recording mute switch Mesa likes to hide them in non obvious places. On a Mesa combo I had it was hidden on the under side of the chassis inside the back of the cabinet. I inadvertently switched the amp to mute while moving it and then couldn't figure out what was wrong for an embarrassing amount of time I wouldn't expect the speakers to hiss with a mute switch triggered, but who knows with a Mesa design.

[Redline]

If the volume knob affects the hiss that may mean that the amp is working fine from the volume knob forward. Of course I don't know which "volume" knob you're referring to.?. I think that amp has several. At any rate, if it's a channel master volume then signal seems to be getting through the effects loop ok. If it's the effects master then there still may be a problem with the loop. Which might explain why no signal was present when you plugged into it. Please tell us which volume and tone controls affect the sound you can hear at the speakers. Start with all volume controls up then listen as you back each one down and report on exactly which knobs effected what and how.

P.S. This may sound dumb (I certainly felt that way) but if that amp is equipped with a recording mute switch Mesa likes to hide them in non obvious places. On a Mesa combo I had it was hidden on the under side of the chassis inside the back of the cabinet. I inadvertently switched the amp to mute while moving it and then couldn't figure out what was wrong for an embarrassing amount of time I wouldn't expect the speakers to hiss with a mute switch triggered, but who knows with a Mesa design.

I'm talking about the channel volumes.

[g1]

So that would mean the fault should be somewhere before the Channel volumes. If the rest of the amp can amplify hiss, it can amplify signal. That's why I think the loop should work when you go in the return, so that is odd.

[Jazz P Bass]

P.S. This may sound dumb (I certainly felt that way) but if that amp is equipped with a recording mute switch Mesa likes to hide them in non obvious places. On a Mesa combo I had it was hidden on the under side of the chassis inside the back of the cabinet. I inadvertently switched the amp to mute while moving it and then couldn't figure out what was wrong for an embarrassing amount of time I.

Ha!
I saw this happen once. Not by me but the customer.
Mesa Nomad.

[g1]

If this is your amp, you probably know this, but I will mention it anyway as it has given me trouble.
For the FX return jack to work, the rear panel "loop select" switch needs to be set to "loop on org & red", the rear panel FX return mix pot should be set to "100%", & the front panel "loop active master" pot needs to be turned up.