Dying VaxStation 4000 VLC - help?

From: Mark Tapley <mtapley_at_swri.edu>
Date: Mon Nov 18 17:46:00 2002

Tony wrote:

> <88W> ... since
>it's steady, I think we can assume it's correct (at least for the moment).

OK. I'll probe around looking for a resistor connecting high end to +5V.

>What I would _expect_ is the following :
>
...
>
>2) A potential divider across one of the supply rails (probably the +5V
>rail), with the tap to the other input. Possibly a capacitor from the tap
>to ground to provide a bit of power-on delay. The idea is to take the CPU
>out of the reset state when the supply rails are high enough (== when the
>comparator switches over)

The orange 6192 may be that. Its job is just to make sure the
voltage-divider tap comes up slower than the voltage reference?

I'll look for another component (a black one this time) in parallel with
the 6192, to form the bottom end of the divider.

>3) A high value resistor from the output back to one of the inputs to
>provide a bit of hysteresis and prevent the darn thing oscillating. May
>not be essential, but it's good practice to put it in
Received on Mon Nov 18 2002 - 17:46:00 GMT