Re: VGC update

[spec@vax2.concordia.ca (Mitchell Spector)]

In article nathan@visi.com (Nathan Mates) writes...
>
>In article <32516836.DC0@ix.netcom.com>, JB  <jbcole@ix.netcom.com> wrote:
>>Does anyone know about the VGC update Apple was doing for certain IIgs
>>models?
>>What exactly does this fix and is it still available?
>
>   Color fringing on certain double hires screens, a few other things.

    To be a little more specific, it affected monochrome Double-Hi-Res
and the 80 columns text display. Usually it appears as stray bits of pink
garbage on screen that flickers (on the text screen it appears inbetween
the dots that make up characters).

    Color DHR screens (and HR for that matter) normally have fringing
because certain color combinations can "bleed". It should also not be
confused with convergence problems that RGB screens can experience.
You'll probably know if you have it, it is _not_ subtle if anyone
is wondering. It would be noticable in MouseDesk or AppleWorks for
example, and be quite annoying (I've seen the faulty VGC in action :)

>Only applicable to the earliest revisions of the GS; if your GS was
>upgraded to a ROM 01, they should have upgraded the VGC as well if it
>was defective. (The ROM 01 upgrade was 2 chips: ROM and VGC) If it was

    That isn't true. The ROM 01 upgrade consisted of a single chip
swap, the 128K firmware ROM. The VGC upgrade was completely separate
and it only affected (as you mention above) the earliest made GSes.
Check underneath your GS, if the first three digitals in the serial
number are 703 or lower, then it has (or had) the faulty VGC. If you
have 704 to 724, then just the ROM is affected.

>bought as a ROM 01 or 3, it should be fine.

    As noted above, some ROM 00's shipped with good VGC chips, it was
basically just GSes manufactured in 1986 that would need both the VGC
and ROM upgrade. 

Mitchell Spector
spec@vax2.concordia.ca