Current System/Problem:
When setting the bias for U2, with DMM clipped on pin 4 and 6 of U2, I am reading 15 V, it climbs slowly, and it gets extremely hot. I have already fried one SC99 and ordered/received another. Both SC99's are working; I have tested in the other module
J6 and J7 are set to adjust, I have a jumper at across J1and J2 as the assembly instructions show. J3 and J4 are set to CGND. J5 is jumped.
Things I have tried tested:
1) both sc99 are reading correctly when I test them in U1 and I am able to set the bias for U1 with either SC99.
2) I replaced U3 LT1013CP. Why? I installed it at U9 on accident (it was really really late
). I used a heat gun to remove it and thought I damaged it. I am also afraid the board is messed up? I don't know how to tell.
3) I am able to set the correct Voltage of +-24 V using the V+ and V- adjust and checked them at pins 3 (+V), 4 (ground), 5 (-V) of U1 and U2.
4) Just for giggles I tested pins out, in, and ground of U6 and U7 and got the correct readings
out=+12/-12V
ground=0v
in=+24V/-24V
5) I replaced C21 because it, uh, discharged when I shorted it, on accident of course!
6) I thought it might have to do with R47 (bias 2 adjustment) and it is warm when powered up, but nothing scalding or suspicious.
I have built 5 other boards successfully, I guess this board was the one I was going to screw up royally. At this point I am even doubting that the J99 I think is good is working as it should, I have no control module to test it against. Almost tempted to buy an assembled one just to make sure the one I think is working IS working. Any help would be greatly appreciated. I have limited knowledge in electronics...
Thank you in advance!!!
