Mesa Triple Rectifier: only power light, no channel lights and no sound

[DS-1]

Hi guys,

I have a similar issue like the one in this post: http://music-electronics-forum.com/t42620/#post443791

I have a Triple Recto that tonight stopped to work: I turned it off to add the pedalboard to the wall socket and then turned it on again. After this, only the red power light works, no channel lights on and no sound.

Can you please explain me better where are these four diodes in the amp? I'll try to check it.

Thanks in advance for the reply!

[drewl]

Read my reply in the thread you quoted.
I'm seeing more and more of these come in for this problem

[DS-1]

Read my reply in the thread you quoted.
I'm seeing more and more of these come in for this problem

Thanks, drewl!

Can you please indicate me where are located these 4x1N4007? I've checked all 1N4007 on the board, but they seem to be fine (I didn't desolder them, I have to say).

Also, can you help me in disassembly the main board?

This is my rev. board.

[drewl]

In the middle of the main PC board there are four 1N4007's.

Is the board under them burned or didcolored?
Even though they may measure good, they might not work under load.

Measure the dc voltage between pins four/five and pin nine on either of the first two preamp tubes on the left.

Also check for ac filament voltage on the same pins as the other preamp tubes on the right.

[DS-1]

In the middle of the main PC board there are four 1N4007's.

Is the board under them burned or didcolored?
Even though they may measure good, they might not work under load.

Measure the dc voltage between pins four/five and pin nine on either of the first two preamp tubes on the left.

Also check for ac filament voltage on the same pins as the other preamp tubes on the right.

The board color seems normal. Also, I find very hard to disassembly the board (I would like to check it on the back). I have electronic rudiments and I disassemble a lot of technologic things, but I never disassembled a tube amp like this.

Tomorrow I'll do the measurement you asked. Do I need to do it with the amp powered and with all the tubes on?

[drewl]

Turn the power switch on, standby can be off or on.

Believe me, if possible you don't want to pull the main PC board if you don't have to.

Those diodes can be replaced CAREFULLY from on top, if that is the problem.

Quick check: do you get any sound if you plug a guitar into the FX return jack with the loop on?

That will tell us if the power amp is working.

[DS-1]

Turn the power switch on, standby can be off or on.

Believe me, if possible you don't want to pull the main PC board if you don't have to.

Those diodes can be replaced CAREFULLY from on top, if that is the problem.

Quick check: do you get any sound if you plug a guitar into the FX return jack with the loop on?

That will tell us if the power amp is working.

Something really strange happened...

I put the jack in the return and only two buzzes came from the cabinet. No sound at all. So I removed the jack from the guitar and started to press it with the finger. No buzz came from the cabinet. Still no sound.

Then I put the head in standby and while I moved the switch, I've heard an increasing whistle from the speaker. So lifted the standby...and I heard the buzz from the speaker while I put the finger on the jack! And the clean channel had the green led ON...and the head started to reproduce SOUND, from return and from the input.

Now everything works like nothing was broken...any idea?!

[eschertron]

See if this makes any sense http://music-electronics-forum.com/t28549/

[DS-1]

See if this makes any sense http://music-electronics-forum.com/t28549/

Thanks for the link!

I don't know if the issue can be this...I only know that my finger did the trick!

Also, I have to say that it wasn't only a sound issue: the amp had all the channel leds off, but after the "whistle", the green ch1 led appeared...

[DS-1]

Last night, the issue was back again.

I turned on the amp, the orange led of the second channel was on, then after a couple of minutes it disappeared: the amp was mute again.

I didn't changed the 4x1n4007, I think I'll do it tomorrow hoping it will fix the issue.

[DS-1]

Turn the power switch on, standby can be off or on.

Believe me, if possible you don't want to pull the main PC board if you don't have to.

Those diodes can be replaced CAREFULLY from on top, if that is the problem.

Quick check: do you get any sound if you plug a guitar into the FX return jack with the loop on?

That will tell us if the power amp is working.

Now that the issue is back again, I have no sound putting the guitar in the FX return jack with loop on.

[DS-1]

I got my amp repaired from a tech, but a year later a similar issue is back: it's a couple of days that my Recto, after 10-15 minutes of playing, starts to sound like there are some interferences, but not that loud, so I can still play. After a while, sound and channel light turns off for a second, like turning off the amp, then sound and light comes in again.

If I choose a channel via back panel, bypassing the Mesa pedalboard, the lights on the footswitch don't turn off completely, but stay on with lighter lights.

Here's a video of the issue: https://drive.google.com/open?id=1vf...grasUNIBKE4K-P

Anyone with a similar issue?