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Did I smoke my 99oC?
Posted:
Mon Sep 03, 2007 2:28 pmby Bmushal
Finally got my J99 assembled. Got through all the testing. Moved my jumpers back to normal. Voltage went to zero like it was supposed to on both at pin 6. Left it on for a couple more minutes and tested again. My probe slipped and now I'm getting 14v on pin 6 of both 990's plus U4 is getting balzing hot. It wasn't before.
Did I ruin my 990C's?
Posted:
Tue Sep 04, 2007 11:49 amby tpryan
Set the regulators for +/-18V. Set the jumper at J6 to ADJ. Short pins 1, 2, and 3 together at CONN1. Install an op-amp at U1 only and apply power. If the output voltage (pin 6) goes to some large value (usually close to either the positive or negative supply voltage) and stays there, you have a bad part. Test each 990C and let us know what you find.
Posted:
Wed Sep 05, 2007 7:44 amby Bmushal
I tested each opamp. Sure enough, the opamp that my probe slipped on is passing full voltage. The good news is that the other opamp is ok. I guess if U1 passes full it series to the next hense the initial reading that BOTH were shorted.