On Fri, May 3, 2024 at 05:38 AM, Scott Townley wrote:
Ozan,
Thank you for the tips.? My observations:
1. I was able to verify +15VF, +5A and +10UF voltages directly on A7.? I need to get an extender to really dig into it :-(
2. In the system diagnostics, +10V Reference (presumably +10UF?) is quite unstable
3. In verifying +10UF, I measured at one end of R105, which connects +10UF to V(REF)+ of the DAC in the third converter ref_cal circuit.? Not knowing which end was which, it was easy enough to find the +10UF (and checking with an o-scope it's quite stable, unlike the system diagnostic), but as it happens the other side of R105 has a very small voltage on it (less than 100 mV).? This doesn't seem right to me.??
As I await my extender, any further insights would be appreciated!
===
Hi Scott,
Other end of R105 goes to a virtual ground inside the IC , seeing ~0V is expected. Current through R105 becomes the reference current for the DAC.
+10V test voltage should go through muxes mentioned in the previous message and show up as 1V at top of R18 (ANA_TEST). If you see 1V then this board is fine, the issue is either connectivity between this board and the CPU board or the MUX on the CPU board is damaged.?
Instead of extenders I usually solder kynar wires to critical test points and take out for measurement. At the measurement end I put different number of knots to distinguish which wire is which. A battery powered soldering iron works well for these small soldering jobs.?
Ozan
