Just received a 1981 IIB... Everything look original to the experts here?

[GreyHills]

I just got this a few days ago. There is an electrical crackle when I hit a low note... not sure if tube, or if it is because of the "warty" looking caps. I am guessing I need to drive over to Petaluma and get this thing worked over by Mesa Boogie. Its a RP-8C board. Does everything else look original to the experts here? I have a DR C+ (serviced by Mike in 2016) seen below, and this IIB already has a nicer clean tone, even with bubbly caps.

 

[McBarry]

G'Day GreyHills,
looks all totes original..
Eg, timber between p/trans and choke, the GE MOV, plate resistors, and of course caps.. everything looks ex-factory.

Re crackle on low notes - rather than hypothesise, suggest change PSU caps, clean the shitters outta both PCB's (I've has crackle from DC between tracks due 30-yr old crud/nicotine/dust etc etc etc) as a start.

At that point, U can re-check symptoms, or just proceed with rest of service - clean pots/jacks/sockets, check voltages etc etc. The only "problem" with the latter is if it resolves the symptoms, U haven't really proven the cause, and hence any real "provability" of the solution. Thus symptom may well return, causing angst and aggro...

Guessing you've verified it's NOT the spkr, or fret buzz ?

Congrats on tasty amp..!
Dave

 

[GreyHills]

G'Day GreyHills,
looks all totes original..
Eg, timber between p/trans and choke, the GE MOV, plate resistors, and of course caps.. everything looks ex-factory.

Re crackle on low notes - rather than hypothesise, suggest change PSU caps, clean the sh!t outta both PCB's (I've has crackle from DC between tracks due 30-yr old crud/nicotine/dust etc etc etc) as a start.

At that point, U can re-check symptoms, or just proceed with rest of service - clean pots/jacks/sockets, check voltages etc etc. The only "problem" with the latter is if it resolves the symptoms, U haven't really proven the cause, and hence any real "provability" of the solution. Thus symptom may well return, causing angst and aggro...

Guessing you've verified it's NOT the spkr, or fret buzz ?

Congrats on tasty amp..!
Dave

Thanks McBarry,

yeah I couldn't figure out what the crackle was for the life of me. I decided to just drive over and drop it off at Mesa Boogie and let Mike B figure it out :mrgreen: So he went through and changed all the caps (some had the 'bubble' of a soon to be dead cap), rotated around the reverb tank, and changed some pots, plus other general maintenance. I pick it up this week so I am excited to hear a revived IIB!

Will post pics of the servicing upon arrival.

 

[Wizard of Ozz]

That looks clean. All original. Nice. :mrgreen:

 

[GreyHills]

Picked it up from Mesa Boogie today. Mike B went over the amp, replaced all electrolytics, and some pots, something about replacing humbucking torroid type coil bands on the EQ, plus all the usual maintenance work. One thing thats new is the Jack that he put into the bottom side of the chassis... "Says "Pull to use gain boost"... Does that mean whiles it's plugged in, I wont have gain boost?


AFTER SERVICING PICS

Nice fresh IIB now 8)

 

[McBarry]

That is one tasty vintage beast - congrats..!
Re removable plug - I'm not sure.
Best I can think if is try it and see..!!