Bug #269
K2 : ERROR 304.6 - Ohms sources; 70nA and 770nA
Start date:
07/18/2012
Due date:
% Done:
0%
Estimated time:
Description
Cannot measure 0.7V ±0.07V at A/D IN.
Switches in R354 for the 70nA ohms source by closing the analog switches at pins 1 and
12 of U332. Q324 (HI OHM pulled low) is on while Q312 and Q320 are off. This selects
R354 as the only source resistor. No other resistor is in parallel with it. The load is again
R394 and is connected to common through Q328. 7V will appear across R354. Op Amp
U322 is set up for x1 gain. Measure 0.70V at A/D IN.
Suspect:
R354 and Q324.
Updated by tin over 10 years ago
- Status changed from New to Resolved
Seems ok after replacement Q330 and Q512 DJFET from #3