Mesa Boogie Dual Rectifier issue!!!!

[Herbie129]

Alright straight to the point. I have a Mesa 3 channel dual rec. it's not the reborn dual rec with the wattage switch. The problem I'm having with it is what seems to be that my V1 and V2 preamp tubes do not seem to be getting power. I've checked the tubes and have changed them with other working preamp tubes but nothing seems to be working. The weird part is I get power to the amp. My power tubes and rectifier tubes are all working fine as well as the rest of the pre amp tubes. Just not V1 or V2. I've also just for sh*ts and giggles have reduced power to 50 watts by removing the inside 2 power tubes and one rectifier tube to see if that might change anything. Now it gets weirder. Prior to receiving no sound from the amp. I swapped pre amp tubes when this happened before and got sound for about 10 seconds before the sound went completely dead. While that happened I had channel changing capabilities with the footswitch and each LED corresponded correctly on the amp. Now I get no indication of what channel I'm on with or without the footswitch hooked up. And no sound at all from the amp. Now I'm not a complete noobie with tube amps but this one has me stumped. I have not yet pulled the amp apart as I was hoping someone on here might be able to give me an answer as to something I might have overlooked or forgot or something. I've done the basics already.

 

[RJF]

Honestly, I would box it up and send it to Mesa, since it doesn't sound like a simple tube issue. Mesa will repair it quickly, and you will be pleasantly surprised on how cheap your bill will be. I have brought a couple of amps to them in person, and they are top notch on the repair side.

 

[dirtyfunkg]

If you're located close to the Mesa HQ, follow the guy above's advice. Otherwise, shipping the amp may cost more than the repair itself.

Do you have any Mesa authorized techs in your area?

 

[Herbie129]

Closest one is about 8 hours away from me.

 

[glip22]

I would open up the amp and reflow solder at the heater connections from V3 to V1. Pins 4 and 5 and pin 9 on the three tubes. Could be a cold joint.

 

[Herbie129]

I'll see about cracking it open tomorrow and taking a look. I appreciate the help

 

[glip22]

I'll see about cracking it open tomorrow and taking a look. I appreciate the help

If V1 and V2 are not lighting up they are not getting heater voltage. You can probably find the problem spot with your multi meter checking the voltages or lack thereof. You should see approx. 6.3 volts between pins 4 and 9. Pin 5 is tied to pin 4 in parallel

 

[Herbie129]

I'll see about cracking it open tomorrow and taking a look. I appreciate the help

If V1 and V2 are not lighting up they are not getting heater voltage. You can probably find the problem spot with your multi meter checking the voltages or lack thereof. You should see approx. 6.3 volts between pins 4 and 9. Pin 5 is tied to pin 4 in parallel

I havnt been able to get around to tearing it apart like I had hoped to. Hopefully by this weekend ill break it down on a bench and see what the real issue is. Im sure ill be bugging the hell out of you when the time comes good sir.

 

[Herbie129]

So I've cracked it open. Everything seems to be ok. Solders are good. Nothing seems to be blown. I'm a bit weary on testing the voltage. As I get a bit paranoid when it comes to electric components. So if anyone has more details on how to go about testing the pins that would be great. Again amp gets power but no sound and v1 and v2 show no signs of receiving any signal.

 

[Herbie129]

I completely bypassed the preamp section by plugging my guitar into the return of the effects loop and I get static for sound which leads me to 100% believe that the problem definitely lies within the preamp section. But what's weird to me is how I don't even get any lights on the amp. Not even for which channel I'm currently on. This amp is becoming a headache

 

[glip22]

Did you replace the HT fuse just for the hell of it? I would just replace both fuses. Mains and HT. Don't test them, just replace them.

 

[Herbie129]

I didn't think the dual rec had an HT fuse. I saw the one on the back of the amp which doesn't need replacing since the amp powers up and stays on.

 

[Herbie129]

Bump

 

[steve_k]

your problem is probably on the low voltage (6.3V) lrh of the power transformer. no preamp heater current. this also powers the LED's. need to send the amp to a mesa tech.

 

[Draggin]

Hi did you ever resolve the issue with the preamp tubes not working?