Re: ZipGSx Upgrade Problem??

[supertimer@aol.com (Supertimer)]

marvinisnot@home.com (Marvin Miller) wrote:

>Hi;
>
>I have a ZipGsx that I just did an upgrade on. Specifially, I soldered
>in (4) .300 sockets and installed new cache memory chips. All went
>really well with the work, it took a while (about 4 hours) but came
>out looking more/less like no one had been there!! I was, and am, very
>pleased with the work.
>
>I bought 4 new chips for the card and I'm wondering if this is where
>the problem lies. Here's the deal;
>
>I bought (2) 32kX8 SRAM's at 15ns AND
>I bought (2) 32kX8 SRAM's at 20ns
>
>On the card there are 4 sockets labelled;
>
>TAG, DATA than TAG, DATA
>
>Understanding that the TAG should be faster than the data, I put the
>chips in like this;
>
>15ns 20ns 15ns 20ns
>
>I than went in and changed the  7&8 DIP switches to OFF as per the
>FAQ. I plugged it in and it didn't work! I got worried a little, but
>realizing that everything had went so well with the soldering - I
>changed the 7&8 dips back to were they were and re-tried. Presto!
>All works well as long as the Zip's Dip's are set to 32k. This Zip
>originally had 32K but should now have 64K.
>
>So, I'm wondering if I have the chips in the wrong order or something
>like that? The memory I bought were just standard 32kX8 SRAM's with
>two being a little slower than the rest.
>
>Anybody have any ideas?

This is why adapters are a better idea than soldering in a smaller
socket.  These accelerators are rare and easy to damage in this
way.

What may have happened is a damaged connection either from
the desoldering or heat from the soldering iron damaging a trace.
Luckily, it looks like the bad connection is in a pin only used for
the 64k size not for the 32k one.  This means that the first set
of sockets (the two on the left with the board facing you) are
good but the bad connection is somewhere in the second two.
To verify this, swap the two chips from the left set with the
right set.  If the board boots up with the 32k setting still, then
the problem is in the sockets.  If it does not boot up after the
swap, one or more chips in that set are bad.

Don't worry, you won't lose much speed.  The TWGS only goes
up to 32k and we don't notice it.  ;-)

Just change the processor and oscillator.  This will give you a
much bigger performance boost.