Hello,
I have an old NI PCI-6025E that pasees all the self diagnostic tests (DAQ Diagnostic Utility) and will self-calibrate, but actually doesn't work in practice:
Specifically:
-digital I/O works ok. Most of it anyhow... (line 0.0 is stuck high for some reason)
-analogue output doesn't work at all
One outputs ~4.4V continuously
One outputs 0V continuously
(regardless of what you do in NI MAX)
-analogue inputs don't work
ai0, ai1, ai2, ai3, ai4, ai5, ai6, and ai7 all "float" towards the 10V rail
ai8, ai9, ai10, ai11, ai12, ai13, ai14, and ai15 all "float" towards the -10V rail
(with the inputs tied to AI GND or +5V externally when viewed in NI MAX)
It's an old board that's new to me. I think somebody has fried the analogue input/output stages. I'd like it fixed for some little projects here but am assuming that an official fix on such an old board will be prohibitively (>$100) expensive.
Looking at the block diagram of the device on pp20 here:
One way that this particular could pass a self-test but failed to work (on the analogue inputs) is if the Analogue Input Muxes are frazzled, right? Are these the MAX337s on the board? (U14 being the one connected to resistor arrays that I assume takes all the inputs. Are there any other failures that could cause the self-test to pass ok, but the analogue inputs not to work?
On the analogue output side the two LTC7545s are the DACs. Presumably these are ok but some buffer stage has failed if the self-test is passed ok but the outputs don't work? Is there any common point of failure to all of the above?
If I can have the analogue input working again that'll largely "do" for me. Any advice appreciated!
Cheers,
--
Marko