Apple IIgs question..

From: David Holland <dholland_at_woh.rr.com>
Date: Wed Jun 4 19:57:00 2003

Hi,

Wandered downstairs, and dug out my pile of parts.
(and more importantly a spare ROM 01 system.) My testing was on a ROM 03.

Thanks for the parts offers, I think I've enough parts now though..
(The wife eye's me evilly every time I drag out my parts pile anyways :-) )

I checked the voltages.

The worst I saw as -10.2v (on what aledged to be the -12v pin) on the ROM03.

The ROM 01's voltages were all pretty normal.

There's nothing else plugged into the systems for the last couple of tests
I just ran. This scope I have is fairly old, and probably not terribly
accurate, but about the best I've seen is +/- 4.9v.

Neither the ROM 01, nor the ROM 03 will talk to the PC.

At this point, I'm wondering if the IIgs's normal "serial" is on the
low side of valid, and my PC's (mis)wired for the high side. I'll
try the serial ports on my Linux firewall.

Data sheet for the AM26LS30's on the thing doesn't make sense to me either
at this point.. but that's besides the point..

Anybody got a schematic for the whole GS? :-)

David

On Wed, 4 Jun 2003, Ian Primus wrote:

> Sounds like a weak PSU, I have had no trouble using ADT on a IIgs. How
> much stuff do you have connected to it? I know I have found that after
> two Unidisk 5.25's, two 3.5" drives, two Disk II's, a SCSI card, RAM
> expansion, etc, etc, it the computer sometimes can't get the juice to
> power drives, I/O, etc (especially those pesky Disk II's)... Try
> measuring voltages at the power supply, it should have the pinouts
> printed on it IIRC. If you want, I have a spare IIgs or two that you
> can have for a few bucks plus shipping. I also have IIe's and floppy
> drives as well, if you want.
>
> Ian Primus
> ian_primus_at_yahoo.com
Received on Wed Jun 04 2003 - 19:57:00 BST