Re: STG2 Outputs

[Jon Elson <jmelson-at-artsci.wustl.edu>]

JohnDRoc-at-aol.com wrote:

> Okay, the plot thickens....  Before sending off the STG card, I put it back
> in the machine and ran the diagnostics again.  The DAC voltages are within
> fractions of the assigned voltages.  This time, the DI's appeared to be
> working properly.  They all started at 1 and grounded out to 0.  I may be
> wrong about the DAC after all (darn it).
> I guess I'll have to go back to the amps again.  I wonder if EMC is sending
> out a strange signal on DAC1?

Well, I have had some strange things happen with my STG (version 1) card.
One time, I fired the system up, and there was no encoder response.
I checked power to the encoders, that was OK.  After much fooling around,
I ran the DOS diagnostics, and the encoders worked fine there.  Then I
went back to EMC, and it worked fine there, too.  I never found out
what was going on, and it never happened again.  I may have jiggled
a loose connection or something, but I powered down the whole computer
and that didn't fix it.

But, you could have had any sort of loose connection, either on the
motherboard-STG card edge connector, the ribbon cables to the
STG card, or whatever.  Or, maybe, somehow the STG diagnostic can
reset some bit that gets set wrong, and can stay that way even through
a power down.  This shouldn't be possible, especially if there is no
backup battery connected to the STG card, but who knows?

Jon