Re: How limited was the Woz edition?

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

In article rubywand@aol.com writes...

>    The VGC replacement seems to vary in significance. We used our Woz
>machine for a few months before the upgrade and, really, I do not recall
>noticing any problems with the display. (Yet, other users talked about
>color fringes at the edges of the display being fixed.)

    I thought I made it clear in my explaination. The faulty VGC problem
*only* affected two emulated Apple IIe video modes, monochrome (560x192)
Double-Hi-Res and the 80 columns text display. Furthermore, it was not a
subtle problem, unless you used odd foreground and background text colors
selections (it showed up best with white on blue). You would probably 
still notice it, and would _definitely_ notice it in mono-DHR mode.

    Native Super-Hi-Res graphic modes were totally unaffected. So if you
never used monochrome DHR (color DHR was fine) and avoided the 80 columns
text screen (40 columns was fine too), then you would probably miss it.

>It may be that, like the ADB Controller IC, some original VGC chips were 
>okay and some were not.

    No, it affected _specific_ chips that could be identified by code number.
It was also pinpointed to specific batches of machines, those with a serial
number starting with '704' or lower (if I understand that code correctly,
it would mean all 1986 GS's and some from the first few weeks of 1987).

    If your VGC has a part number of AMI 344S0046-1 or AMI 344S0046-A,
then it is defective, period. 

>     Does your ROM 00 machine display look different than a ROM 01 machine
>display? If there is no difference, perhaps you will not need the VGC
>change.   

    Another myth is that all ROM 00 machines came with faulty VGC's. 
This was simply not the case.

Mitchell Spector
spec@vax2.concordia.ca