Introduction and Help request...

[wishuponabeer]

Howdy All...First post here.
I am a 56 Yr old retired Network Admin in the process of getting back into My old hobby of fixing / resurrecting old tube amps. While My knowledge of tube stuff is
fairly good, I've never owned a Boogie before. This one came to Me recently in a Horse-Trade; description as follows:
Presented to Me as a MK-llc, but appears to be an earlier MK-llb. DOM 1-22-81 with either MB or M3 below date (Sharpie on Chassis)...(MB = Mike Bendinelli?)
60/100 switch, No Simul-Class
Reverb and Graphic EQ, Hardwood Dovetail case w/ Cane Grill and EVM-12L (and Flight Case)
End of chassis has HR6 and a black Dot
Missing Foot Switch (es) for chan. switching, Reverb, and EQ

I can see where the Reverb cables hook up, but there is what appears to be an additional RCA jack (unlabeled) AND 2 Phone Jacks (I assume for the foot switches)

based on the description, can anyone tell Me: What exactly I have (MK-llb or llc Mod)
What the jacks on the chassis are for, esp. the odd phono jack.
If needed, I can put up a few pics. Thanks in advance for all Your help-

Tom Talbert (wishuponabeer)

 

[dodger916]

Welcome! Now read this: http://forum.grailtone.com/viewtopic.php?t=18184&highlight=mark+iic

Based upon the DOM (1981), it's not a IIC or C+ unless it was upgraded from a B or A. These upgrades are not very common, but they do exist (my C+ is an upgraded A). The serial number is also a clue, but the preamp board will tell the story. Hopefully it says RP11A! You can also perform the "Loop Test" as noted in Boogiebabies' treatise on the C+.

 

[tony777]

To determine whether it's a IIB or C, the C comes with pull shift above the Bass knob.
Serial # above 10000 or something, if the amp was built in 81 its probably a IIB or could be a IIA, if it has an FX loop, it's a IIB.

There should be two Phone jacks beneath the chassis, the one far left is a preamp/poweramp junction jack, the other one is for the EQ/reverb footswitch. There should be two RCA's for the reverb.

The HRG code on the chassis means H: hundred R; reverb, G: graphic EQ.

Mesa boogie user manuals can be found here: http://www.mesaboogie.com/manuals/user_manuals.html#gpm1_2

Good luck.

 

[wishuponabeer]

Thanks, Guys...
The Preamp board is RP-8C; Serial # is 6347 (or, G347) SINGLE RELAY, no LDR
In process of cleaning the pots and switches (a couple are a little crunchy) and running the preamp tubes thru the TV/7U tester.
The Power tubes seem to be recent MESA STR-440s; the preamps are a mish-mash (V1 is a HeatShrink SPAX7 MESA; wonder how old THAT is?)
OT is the 100, not the 105...
Again, I can get some gutshots while it's open if that would help.
Thanks again...

 

[dodger916]

Thanks, Guys...
The Preamp board is RP-8C; Serial # is 6347 (or, G347) SINGLE RELAY, no LDR
In process of cleaning the pots and switches (a couple are a little crunchy) and running the preamp tubes thru the TV/7U tester.
The Power tubes seem to be recent MESA STR-440s; the preamps are a mish-mash (V1 is a HeatShrink SPAX7 MESA; wonder how old THAT is?)
OT is the 100, not the 105...
Again, I can get some gutshots while it's open if that would help.
Thanks again...

That preamp board is not a IIC. Gut shots are always a plus.

Mesa still sells a heat shrink SPAX7-A, known to be a quiet, reliable tube good for V1.