Re: ZIPGS

[Wayne Stewart <waynes@intergate.ca>]

Andrew Webber wrote:
> 
> I finally got hold of an accelerator for my IIGS, but I recieved it
> with no instructions. I have looked on the FAQ and got all the dip
> settings sorted. I am unsure which model ZIP card I have. Its a ZIP GS
> 1.01 with the following chips:-
> 
> + Oscillator - 32Mhz. 2 pin type. Based on the FAQ this should be a
> 8MHz Zip
> + Largest Chip - 9043 WD4701
> + WDC W65C816PL-7 (7Mhz?).

Yes 7mhz, I think that was the fastest available then. 

> + 4 Cache banks. TAG 1 = UM62640-70L, DATA 1 = 6264BL-10, TAG 2
> =6264-70L, DATA 2 = 6264BL-10. Cache size? The system says 16K in the
> CDA.
> 
> Is this a 8Mhz/16K Cache model?

Yes, it is.
The manual (such as it is) might help, you can download a pdf of it 
from my website at
http://homepage.mac.com/waynes

> 
> The problem is that the system hangs every now and then. I thought it
> might be because its actually a 7Mhz/8k card not an 8Mhz/16K card? The
> system will work for a relatively long period then it will just stop.
> This has happened in GS/OS and in a game. I am able to soft reset the
> machine and all is ok, I don't have to power off, so I don't think its
> heat related.

The only difference between the 8k and 16k is that they installed 2 more
SRAM and flipped a switch
Pretty hard to troubleshoot without being able to try different parts.
You could try switching it down to 8k cache and see if it improves or 
gets worse. To do that on the first switch block turn switch 8 to the 
on position. With the power off of course. Another possibility is that 
7mhz processor, it's pretty much maxed out at 8mhz.  If you can score 
a faster 65816 it surely wouldn't hurt.
 
> Also what is the easiest upgrade I can do to this card without
> involving any major work (I would not trust myself with a soldering
> iron!). If its chip replacement does anyone now a good source for the
> right type of cache/processor chips?

Since the oscillator is soldered in on yours, then without soldering the 
only upgrade is to go for more cache. Going from 16 to 64k would give 
you about a 10% speed bump. If you were going to try for higher speeds 
narrow static RAM would be the way to go but since you're not the wide 
Static RAM will work. 70ns is common in the wide package and every 
manufacturer uses slightly different numbers. I'll give you a Hyundai
number HY62256A  LP-70.

I don't recall whether the FAQ mentions it but the plug that goes into 
the processor socket is a bit delicate. If you need to remove the card 
unplug the cable from the card, not from the motherboard.

Wayne