[macmeech]

I have a 102B Jolida with two front tubes which I just rebiased for the first time to 30+-3 mv on the advice of Bill Baker at Response Audio. It sounded great until an hour later when V2 turned all red and made a loud feedback sound. I turned it off, waited an hour, lowered the bias on V2, and then turned it back on. The sound started again and smoke started pouring out of the bottom and then the top of the transformer section. It was pretty funny for a newbie screwup.  
The question is what do I do now?
The tubes are brand new (300 hours) matched EH 84s
but I am worried about internal wiring damage. Anybody got any suggestions?

[Bill Baker]

WOW! Smoke from within the chassis? Something in the bias stage went astray. Even if you over biased accidently (within reason), it would not cause this. There is the posibility that you have a bad bias pot and when adjusting it for the first time in a long while, brought out a problem that was lurking within. Do you have a digital camera to take a close-up PIC of the inside of the amp in that area? You will probably be able to visually see the problem if you take off the bottom plate and look inside. Being a "newbie" I would not recommend touching anything.
  Even a bad tube or resistor would not normally cause this type of situation. Being the older design, I don't recall if you have the circuit board or point to point wiring.

 On the "2 signal tube" versions, 30 mV is the recommended bias setting. Just in case anyone has seen my post about biasing the 102B's at no more than 20mV, as stated this is only for the newer "3 signal tube" versions.

  Feel free to keep me posted on what you find. I am more than willing to help you in this.

[macmeech]

Thank you, Bill for your generous offer to help. I will keep you advised. The McIntosh repair person, Wayne , is on vacation until Monday. I'll let you know what he says when he gets back.