Smoke from Hardy 990c

[mrosso]

Just built a J99. All voltages checked out fine, had 22/-22 on Pin 3 & 5 on both opamp sockets. Plugged into my chassis (PS02) and had some weird output on my scope. My A12 & N72's are fine. Took J99 out of chassis, rechecked voltage and had +22 on pin 3 -.5 on pin 5 on both sockets. Per info on the forum, I resoldered the regulator and rechecked. Now I was back to 20/-20 again. Plugged in the 990c's hit the power and SMOKE!!! Cut power, checked voltages minus opamps again and now it's like .3 instead of .5. Any ideas what the hell is going on?

[tpryan]

Sounds like an intermittent connection somewhere. Can you post a photo of the underside of the board? It's possible to kill a 990 (and many other op-amps) by only applying power to one supply rail, so that may be what happened.