Multibus ST-506/QIC-02 (was: Re: SGI IRIS 1400 ...)

From: Tothwolf <tothwolf_at_concentric.net>
Date: Mon Jul 22 01:48:05 2002

On Mon, 22 Jul 2002 jpero_at_sympatico.ca wrote:

> > I checked the voltage again, with the servo plug disconnected, and got
> > just under 12VDC across the terminals. With the servo plug connected, it
> > reads right at 0.4VDC.
>
> That means poor power drive to kick in that servo. Voltage should go up
> to ~12V or then settle down to holding voltages like 6V or so depending
> on that design.

Would that happen even if the load solenoid is stuck, and the servo can't
move?

> In all TV sets that uses power relay to turn on set using standby power
> it's always either 12V or 24V across coil when on. On one set, I had
> diode go leaky across that coil. That one I could push down on that
> relay and it will stay shut and tv come up. (too weak for initial pull
> in.)

This board uses 2 MJE200 transistors, 2 MJE210 transistors, and 4 1N4001
diodes that appear to form some sort of H-bridge.

-Toth
Received on Mon Jul 22 2002 - 01:48:05 BST