Re: Klunky IIGS - no docs - where do I start?

[duncane@jumper.mcc.ac.uk (Duncan Entwisle)]

David Empson (dempson@atlantis.actrix.gen.nz) wrote:

: No - you set the video scan frequency by using the
: Control-Option-Reset menu.  Items 2 and 3 on this menu are used to set
: the scan rate to 50 Hz or 60 Hz.  They also cause all other Control
: Panel settings to be restored to their defaults.

Isn't this the standard reset? In which case this doesn't produce a menu 
for me :-(

: 15.75 kHz (or thereabout) compared to 30 kHz or higher for VGA.

: Pins?  Definitely not.  It is a matter of the frequency of the scan
: lines being output to the monitor.  The IIgs is outputting about 15750
: lines per second, whereas current monitors expect at least 30000
: lines, and cannot lock onto a slower signal.

Which means that monitors for the Amiga will work (as these are required 
to have a 15.75kHz scanrate - CGA monitors would be fine (at this 
frequency) except for the fact that they are digital rather than analogue 
RGB.

: This error (from the IIgs self-test) means that bit 1 has failed in at
: least one location somewhere in bank E0, which is the first bank of
: "slow" RAM.  It contains the video displays, and is also used by the
: firmware for buffers, memory allocation tracking, parts of the
: operating system, data storage, etc.  The leftover parts can be used by
: programs (via the Memory Manager) if most other memory has been used up.

Right, so I can't get away with just ignoring it :-)

: If you want to replace this chip yourself, I strongly suggest you do
: it by cutting off the pins of the old chip (next to the plastic part
: of the chip), then soldering a new chip (or socket) onto the pins.  Do
: not attempt to desolder the pins from the motherboard, as it is a
: four-layer board, and you could damage it quite easily.

Phew - thanks for that - with luck I may be able to do a board swap with 
a ROM0 IIGS, and swap the ROMs over (I presume this is all that needs to 
be done - the ROMS are socketed)

: Better still, get a professional repair job, or replace the
: motherboard.  Alltech Electronics in the USA does board swaps for the
: IIgs.

Alas, I'm in the UK :-(

Thanks.
Duncan.