Drew wrote:

>> So what the difference is between the two ZIP GSX boards, or should I say
>> the ASICs (large square IC), really isn't know (at least to me).  Maybe they
>> weren't sure about the ASICs ability to work and only has a small batch
>> produced.  Being this was 1989 (?) it was in the middle of the 'custom
>> logic'
>> reevaluation where it was really starting to become 'cheap' to produce these
>> large ASICs.  So if the 1.01 boards kind of worked, and worked good enough,
>> why not sell them?  It's just a business decision at that point.  Then maybe
>> they fixed a few minor reliability issues and produced a second batch,
>> v1.02.  Of course I have no idea what the real story is and I'm just
>> speculating.  In 1989-90 we all kind of knew that Apple II was on its way
>> out.  So that's where I start to consider the 'small batch' theory.

> Thanks Henry for that, didn't really cross my mind that the ASICs
> might be different between the two boards. Looking at the picture on
> your site of the ZIP GSX 1.0.2 the ASICs do indeed look different
> types to the one on my card. I did speak to you about this before, but
> was bugging me that my card had the sockets :-).

My point is that those two chips were designed to do something with signals on 
the card and that the differences between 1.01 and 1.0.2 must amount to more 
than their presence or absence.  In order for it to work without them, there 
must be jumpers to provide the equivalent paths in the circuit topology.

Perhaps they are simply buffers?

So, it sounds like it's possible to upgrade a 1.0.1 rev GSX from what I'm hearing.

> My cards run fine, they never hang, get the odd crash but never sure
> if thats the card or not to be honest. I was happily playing OOTW for
> over an hour at full screen and full 12.5Mhz speed the other night....

Unfortunately, my 12.5Mhz. 1.0.2 board (I have one of each) does not run 
reliably.  If left on it will eventually put the machine in a state where the 
mouse will move the cursor, but nothing else responds (nothing from keyboard 
or mouse buttons).

Maybe I'll have better luck with the 1.0.1 unit.

Steve
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