Help needed to debug QRP-02

[peranders]

If you look at the schematics you see that the 12 V is for the opamps only. The opamp is OK? Do you have the polyester caps on the solder side?

[jamh]

Yes, the caps are on the solder side.  Perhaps the opamp is not ok.  How do I tell without removing it?

[peranders]

Check first that you have mounted in correctly, then you can measure the resistance between pin 4 and 8. If it's blown I'll you should measre near zero ohm.

[jamh]

I think we're on to something.  While res between 4 and 8 is good in both (18.k), I started measuring all the pins and there is something not right between 7 and 6 in the one with the blown traces.  I measured 140ohm between outb and -inb.  In the good one this is 2.3M.  Time to take out the AD8620?

[jamh]

C6 is also blown. It shows 140ohm as well.

[peranders]

C6, is it measured only this or in circuit? The opamp seems to be broken.

[jamh]

In circuit, but in circuit, the value of C6 in the other channel was in the Ms. I'll change them anyways while I'm at it.  Got some nice sounding wimas.

[jamh]

Still waiting on parts..