Could someone open their Boogie Mark III for me?

[jvm]

I have a Mesa Boogie Mark III that has had all of the pre amp wiring unhooked. I have everything repaired except one wire I can't seem to find a home for. The gray wire coming off the PC board between the orange relay and a stacked pair of vactrols. In the photo, the wire is tied to the two shielded input wires and a ground strap but I can't see where it goes. Any help appreciated.

[T9c]

[ATTACH=CONFIG]22697[/ATTACH]

I have a Mesa Boogie Mark III that has had all of the pre amp wiring unhooked. I have everything repaired except one wire I can't seem to find a home for. The gray wire coming off the PC board between the orange relay and a stacked pair of vactrols. In the photo, the wire is tied to the two shielded input wires and a ground strap but I can't see where it goes. Any help appreciated.

What's the grey wire connected to on the PCB? Hard to tell in the picture.You have the schematic? Lemme know if you need one.

.

[jvm]

Hi, T9c. I have a schematic but had hoped to avoid tracing the circuit what with no part numbers on the board. The wire is attached to a resistor between the relay and a stacked pair of vactrols behind and between the middle and master volume pots. I have seen gut shots online and the wire is blue in some amps.

[Alex R]

It's pretty simple, tracing one circuit node, and an indisp[ensable part of troubleshooting like this. Identify which parts the wire is connected to on the board, note their values and anything else that might help distinguish them, check them on the schematic and see what the wire is meant to connect to. That's a whole lot easier than taking the chassis out of an amp, and less likely to lead to confusions and wrong answers. I know you're asking sonmeone to do something different, but what we are suggesting is the right way to go about it, most likely to end in sucess for you.

[soundguruman]

[ATTACH=CONFIG]22697[/ATTACH]

I have a Mesa Boogie Mark III that has had all of the pre amp wiring unhooked. I have everything repaired except one wire I can't seem to find a home for. The gray wire coming off the PC board between the orange relay and a stacked pair of vactrols. In the photo, the wire is tied to the two shielded input wires and a ground strap but I can't see where it goes. Any help appreciated.

MUCH BETTER PICTURES WITH MUCH BETTER LIGHTING, MORE CLOSE UP.
From your picture, it's very difficult to tell. Do you have the terminal (pad) number?
Believe it or not that wire is hooked to a numbered pad on the circuit board. BUT the number is facing DOWN, in the direction of the chassis.
If the wire pad is labeled "V" and the wire grey, it goes to the wiper of the first (left most) gain control.
If the wire pad is labeled "M Gry2.5," it goes to the high side terminal of the (leftmost) clean channel master volume.
BUT it's hard to tell without the pad numbers or better pictures.
Grey wire: it probably goes to the gain or master of the clean channel. Can't tell from the limited info.

But, I tell you what...you are brave to take that abomination apart, and work on it.
Most techs run away from those things. They are hell on earth to repair.
If you fix it and get it working...major respect. (good luck)

[Fragger]

My 2 cents are on this gutshot I found.

[T9c]

Looks like, from Fragger's photo that it is connected to the Vactrol or relay and therefore terminate at the pull switch on the clean channel gain control; possibly...

[jvm]

Thanks for all the input, everyone. Fragger, the gut shot is on the money but doesn't show where the gray wire terminates. I would be happy to try to trace the circuit if I could find a LEGIBLE schematic. The wire is connected to a resistor located BETWEEN the vactrols and relay. If anyone has a legible schematic, I would be most appreciative. As for the kudos from Soundguruman, I didn't know I wasn't supposed to work on Boogies! NOW you tell me! Lol! I have recently repaired a Mark I reissue, a pair of Mark IV's and now this one. The Mark II came to me with several pots missing and most of the pre amp unhooked. I have no idea what the last guy was trying to accomplish!

[Jazz P Bass]

How about this?
What doesn't work on the amp?

[T9c]

Schematic

See if this schem isn't more legible.


Boogie_MKIII_Pre.pdf

Thanks for all the input, everyone. Fragger, the gut shot is on the money but doesn't show where the gray wire terminates. I would be happy to try to trace the circuit if I could find a LEGIBLE schematic. The wire is connected to a resistor located BETWEEN the vactrols and relay. If anyone has a legible schematic, I would be most appreciative. As for the kudos from Soundguruman, I didn't know I wasn't supposed to work on Boogies! NOW you tell me! Lol! I have recently repaired a Mark I reissue, a pair of Mark IV's and now this one. The Mark II came to me with several pots missing and most of the pre amp unhooked. I have no idea what the last guy was trying to accomplish!

[Jazz P Bass]

A whole lot better than the one I had.
Thanks.

[Tom Phillips]

I have a Mesa Boogie Mark III that has had all of the pre amp wiring unhooked. I have everything repaired except one wire I can't seem to find a home for. The gray wire coming off the PC board between the orange relay and a stacked pair of vactrols. In the photo, the wire is tied to the two shielded input wires and a ground strap but I can't see where it goes. Any help appreciated.

Attached is a gut shot of a 1989 Mk III that may help.

[ColinP]

Hi T9C - If you still have that Mesa Mark III schematic I would greatly appreciate a copy. I have a head on my workbench that sounds like a thunder storm - crackling and hissing - and I can't figure out what is wrong with it..
Cheers

[DrGonz78]

Here is the mkiii schematic. Also, this website is pretty good to find Boogie stuff.
http://tubefreak.com/fschema.htm