Mesa Boogie D-800+

[Mars Amp Repair]

Hello folks,
Has anyone have any experience with this D-Class Bass amp? I kinda figure these are just board replacement level type items. This one...

[Mars Amp Repair]

Hello folks,
I repaired many issues with this Ampeg SVT-AR head and am left with one more issue to solve. With all volumes down there is a low but...

[Mars Amp Repair]

Yo folks,
I've searched all over & cannot find the SVT-AR version schematic. Some are similar but none just like it. My issue is in the preamp...

[Mars Amp Repair]

I actually think this guy just happened to notice the issue and was wondering if it was 'Normal' given the special price he paid for it ....

[Mars Amp Repair]

Not sure if I was clear: The ckt I added worked like a charm. As soon as the power is turned off the output is muted. Worked like a charm. Thanx again,...

[Mars Amp Repair]

Well, i hear what you're saying about that final drive ic should still have issues with the supplies going down unevenly. Perhaps there's more to it but given...

[Mars Amp Repair]

Addendum to previous post:
I just realized I didn't elaborate on the power on muting ckt.
The TC components are: C-44 & R59 near U3A.
...

[Mars Amp Repair]

Hey folks,
I apologize ahead of time for the long - windedness!
I have experienced this Ampeg model as well as some others that upon power down,...

[Mars Amp Repair]

Another great troubleshooting technique which we all need on tough issues like ground loops! Years ago I cobbled together a computer monitor & a magnetic...

[Mars Amp Repair]

Hello folks,
Just entering an issue I had with one of these limited edition Vox AC30HW60's that are British made from a few years ago that were probably...

[Mars Amp Repair]

Thanx Delta...

[Mars Amp Repair]

Hello folks,
Does anyone know of a suitable sub for the MosFets in the bias ckt STK830 that are more common? I saw a post on re: the HT Club 40 that...

[Mars Amp Repair]

I believe this is the G-6160 model but the preamp schematic which seems to match the unit is 6141 which I don't see anywhere.
This unit has a standby...

[Mars Amp Repair]

Hey fellow techs,
The symptom is not just a constant oscillation but when you hit a note and them mute it, that's when you get a short spurt of the...

[Mars Amp Repair]

Hello folks,
I posted before about the PRS Sonzera 50 with the intermittent Alpha pots that were stressed as a result of the pot board being suspended...

[Mars Amp Repair]

Ah HAH! That explains a lot! Makes much more sense. I'll have to attack the issue with that in mind. I will say that disconnecting Q21/23 did allow me...

[Mars Amp Repair]

All good info. I really can't determine if this bug is the original or if the LED was replaced or substituted for a bulb...My best guess given what you've...

[Mars Amp Repair]

Well, it would take a super low wattage bulb that is paralleled by a 1.5k resistor to work here as it is fed from a relatively low current 22vdc source and...

[Mars Amp Repair]

Hey folks,
Have a Sunn Solarus 6550 version (goofy looking lounge style combo). The 22V zener diode in the 22v supply for the trem ckt was shorted...

[Mars Amp Repair]

Yeah, I just acquire this Cricket xistor tester, I believe it's one of the older versions as it doesn't have the 6 push buttons as the fancier one did....

[Mars Amp Repair]

Hello folks,
I apologize ahead of time for the diagtibe!

Been working on a Mackie SR1232 power amp section of this powered monitor. I think...