Auto System Check - Trip Computer Dead?

[Garth Gillespie]

On the way home, the system check area of the dash gave out a long
continuous tone and then system check area and the trip computer were both
no longer functional.  The sound (like a low gas beep but continuous) went
away when I shut off the engine and restarted, but the Auto System Check and
Trip Computer are both out.  It is not back light issues, I can't see
anything in the dark either.  Checked fuses hoping to get lucky but nothing.

I have read this is a circuit board on the back of the IC.  Is this
replaceable without soldering?  I'm thinking used-part.

Anyone had this happen before?  Does the ACS also control the trip computer
or should I be looking at the ECU?

Car still runs fine.  All other IC elements work.  All lights and electrical
also ok.  Nothing electrical done to car for over a year.  No work at all
except for oil changes actually.  Nothing recent.

Thanks,
Garth Gillespie
1992 100CS Quattro