New IIc+ DG questions/schematics/gut pics NO V4

[oogie]

Hey everyone, just picked up a IIc+ DG 100 watt and i got a couple questions. This amp is filthy, looks like it hasnt been touched for 20 years. Its gonna need some TLC.

-First, this non reverb model is missing V4. Can anyone explain the lead channel and how it works on these models without a V4?

-Is the bright or dark version and what can be done to increase gain? I find that i need Vol1 10, Treb 10, and lead drive at 9-10 to get the same gain from my other c+ with lead drive at 4-5.

-By the gut pics, what components would you recommend be replaced?

-Im going to be converting to a head and going to be selling the cab & speaker but its in semi rough shape. Not a lot tears in the tolex but stained up pretty good. Any way to remove the stains and clean this up, what would you use?

-whats a fair asking price for the cab & speaker?

-ive heard that reverb could be added but looking at this circuit board and seeing that its missing V4 i dont know how that would be done.

-Which amp tech would you trust to do any ++ mods or adding reverb or anything else now that Mike B is no longer doing mods? Theres gotta be somebody out there that can do these things, it all cant just die when MB retires right?

 

[user 41014]

Nice score.

My observations are that you should reach out to MB for a service order to start a dialog. Send him the chassis and when he has it in his possession ask if he wouldn't mind adding a pull switch for +/++. I would explain the pot level difference in the original communique. Basically back door the mod and since he will tell you he needs to be compensated for his time/mod state your willingness to pay him the extra he would charge if he would do it above and beyond the servicing.

The pots may be failing? Unhealthy pre tube (roll a known good one through)? If there is a bad component he'll find it. Your filters are from '84- any bulging caps? Otherwise they may or may not be bad. 95% of people will tell you to replace them. If the + end of the large cans is black or red I wouldn't be in the 95% unless they tested bad but your window for Mike can't be expected to stay open long.

Pics of the chassis underside? I don't have a SP-11 to compare against but the chassis slot for V4 seems to be in use. You sure there is not a V4 on the front side?

The reverb can be added but without the open real estate in there I don't see Mike doing it and wouldn't ask. We're talking Mesa Mark reverb not Fender. A pedal would be cheaper, not looked hacked in to wherever you can put a socket and sound better/ more options.

I'll defer to someone more experienced on the lead stages. If there is no V4 (ignoring the PI) I would assume V3 is handling both triodes for the lead. Otherwise it is my understanding V4 should be there regardless with the lead circuit split between one triode each of V3 and V4 leaving an open triode for both sockets.

$200-300 cab/speaker?