Re: Apple IIgs ROM3 dead

[Michael J. Mahon <mjmahon@aol.com>]

STYNX <stynx@gmx.de> wrote:
> I checked each pin of the slots and cpu for a short. I found that between
> 5V and ground there is only 40 Ohm resistance. i would consider that
> shorted. The slots are most likely not the problem, since i have put a
> full-lentgh piece of 1mm plastic in each. I think, that either a IC or a
> capacitor may be blown. I have already replaced all capacitors in the PSU-area, no change.
> Only the Z80 near the 3.6..Mhz oscillator gets warm (more than any other
> on the board, but not hot)
> This really stinks. A replacement Rom3 MoBo is not that easy to obtain,
> especially in germany.

40 ohms to ground from the +5v is not much of a short--it's only 125ma of
current and a half watt of power dissipation. 

However, if it is a leaky capacitor, 1/2 watt is enough to make it
noticeably warmer than others. 

Depending on your VOM, it may also be a normal reading. 

BTW, Z80???

-michael - NadaNet 3.1 and AppleCrate II: http://home.comcast.net/~mjmahon