Polymorph

Hi All,

As promised in another thread, I have posted details of how I modded my
Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
pictures of how to perform the modification to your board (if you are game).

Check it out, and let me know what you think:

http://apple2.sytes.net/ZIP_GSX_Mod/index.html

The usual disclaimers apply - if you break your board, its not my fault!
:-)

cheers,
-p

winston19842005

On 9/23/07 9:33 AM, in article 46f66b15@news.comindico.com.au, "Polymorph"
<mike.a.stephens@gmail.com> wrote:

> Hi All,
>
> As promised in another thread, I have posted details of how I modded my
> Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
> pictures of how to perform the modification to your board (if you are game).
>
> Check it out, and let me know what you think:
>
> http://apple2.sytes.net/ZIP_GSX_Mod/index.html
>
> The usual disclaimers apply - if you break your board, its not my fault!
> :-)

Wow, that looks easy! How hard is it to get the parts? Couldn't find some
0.6" SRAMS for the TAG sockets?

Then anyone could do it...

(sorry, don't have a GS, but I was curious...)

Steven Hirsch

Polymorph wrote:
> Hi All,
>
> As promised in another thread, I have posted details of how I modded my
> Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
> pictures of how to perform the modification to your board (if you are
> game).
>
> Check it out, and let me know what you think:
>
> http://apple2.sytes.net/ZIP_GSX_Mod/index.html

Very cool idea! I was planning to remove the 0.6" DIP socket outright with a
vacuum desoldering station. Your approach is a _lot_ safer.

I notice you didn't replace the two 74F parts. When/why is this necessary?

Steve

Polymorph

On Sep 24, 3:41 am, Steven Hirsch <snhir...@gmail.com> wrote:
> Polymorph wrote:
> > Hi All,
>
> > As promised in another thread, I have posted details of how I modded my
> > Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
> > pictures of how to perform the modification to your board (if you are
> > game).
>
> > Check it out, and let me know what you think:
>
> >http://apple2.sytes.net/ZIP_GSX_Mod/index.html
>
> Very cool idea! I was planning to remove the 0.6" DIP socket outright with a
> vacuum desoldering station. Your approach is a _lot_ safer.
>
> I notice you didn't replace the two 74F parts. When/why is this necessary?
>
> Steve

The original hypercard stack used 0.6" to 0.3" adapters to fit the
high speed SRAMs, but I thought that they were way over-priced and
also increased the width of the board to the point that the slot
adjacent to the Zip GSX would probably become useless due to
encroachment.

If you want to go much higher than 12.5Mhz it *may* be necessary to
replace the 74F parts. Some people have reported getting 15Mhz using
the 74F parts, whereas others have had to do the 74ACTQ replacement. I
wanted to keep my mod as simple as I could for now - I didn't want to
have to desolder anything from the board as I do not have good enough
tools at this stage (the traces are very small and numerous). I hope
to eventually try pushing the card to a higher speed, but I'm pretty
stoked with 12.5Mhz at this stage - it is quite noticably quicker than
8Mhz with 16K cache. I expect I could go a little higher than 12.5Mhz,
but I don't have any crystals between 50Mhz and 64Mhz to test with
yet.

cheers,
-p

Polymorph

On Sep 24, 1:06 am, winston19842005 <bjjlya...@bellsouth.net> wrote:
> On 9/23/07 9:33 AM, in article 46f66...@news.comindico.com.au, "Polymorph"
>
> <mike.a.steph...@gmail.com> wrote:
> > Hi All,
>
> > As promised in another thread, I have posted details of how I modded my
> > Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
> > pictures of how to perform the modification to your board (if you are game).
>
> > Check it out, and let me know what you think:
>
> >http://apple2.sytes.net/ZIP_GSX_Mod/index.html
>
> > The usual disclaimers apply - if you break your board, its not my fault!
> > :-)
>
> Wow, that looks easy! How hard is it to get the parts? Couldn't find some
> 0.6" SRAMS for the TAG sockets?
>
> Then anyone could do it...
>
> (sorry, don't have a GS, but I was curious...)


Did you miss the parts list I created?? It lists all the part #'s for
the parts I used and links to the respective company web sites. I
anticipated that people would probably want to know this, and I am
surprised you missed it. The table is at the top of the page before
the steps for modding...

cheers,
-p

Warren Ernst

On Sep 23, 5:23 pm, Polymorph <polymorp...@hotmail.com> wrote:
> On Sep 24, 1:06 am, winston19842005 <bjjlya...@bellsouth.net> wrote:
>
>
>
> > On 9/23/07 9:33 AM, in article 46f66...@news.comindico.com.au, "Polymorph"
>
> > <mike.a.steph...@gmail.com> wrote:
> > > Hi All,
>
> > > As promised in another thread, I have posted details of how I modded my
> > > Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
> > > pictures of how to perform the modification to your board (if you are game).
>
> > > Check it out, and let me know what you think:
>
> > >http://apple2.sytes.net/ZIP_GSX_Mod/index.html
>
> > > The usual disclaimers apply - if you break your board, its not my fault!
> > > :-)
>
> > Wow, that looks easy! How hard is it to get the parts? Couldn't find some
> > 0.6" SRAMS for the TAG sockets?
>
> > Then anyone could do it...
>
> > (sorry, don't have a GS, but I was curious...)
>
> Did you miss the parts list I created?? It lists all the part #'s for
> the parts I used and links to the respective company web sites. I
> anticipated that people would probably want to know this, and I am
> surprised you missed it. The table is at the top of the page before
> the steps for modding...
>
> cheers,
> -p

Re: narrow chips and wide sockets

I was basically SHOCKED at the price of the .6" to .3" converters for
the new RAM chips, but I did something else instead.

I found several ZIF (zero insertion force) sockets that fit into .6"
sockets (as found on the Zip GSX) but accepted BOTH .6" and .3" chips.
I don't remember the prices exactly, but I think the converters were
$12 each while the ZIF sockets were $2 each.

Here's a photo: (not the exact unit, but it looks pretty close
http://www.dontronics-shop.com/40-Pi...s-p-16192.html

I have my ZipGSX in slot 4 and there's nothing in slot 5, so the space
consumed by the sockets aren't a problem.

Food for thought.
-Warr

Scott Alfter

In article <C31BF953.4D3D%bjjlyates@bellsouth.net>,
winston19842005 <bjjlyates@bellsouth.net> wrote:
>On 9/23/07 9:33 AM, in article 46f66b15@news.comindico.com.au, "Polymorph"
><mike.a.stephens@gmail.com> wrote:
>> As promised in another thread, I have posted details of how I modded my
>> Zip GSX to run at 12.5Mhz. It includes the complete parts list, and
>> pictures of how to perform the modification to your board (if you are game).
>>
>> Check it out, and let me know what you think:
>>
>> http://apple2.sytes.net/ZIP_GSX_Mod/index.html
>
>Wow, that looks easy! How hard is it to get the parts? Couldn't find some
>0.6" SRAMS for the TAG sockets?

I used 12-ns SRAM for both tag RAM and cache on mine, so it has the narrow
chips all across. Then again, I think I paid nowhere near $12 per chip for
it...JDR isn't exactly the cheapest place to buy this stuff.

I've had trouble in the past getting it to run reliably beyond 8 MHz,
though, even with a 14-MHz processor and with whatever 74Fxx parts are
supposed to be replaced with 74ACTxx. With the upgraded power supply that's
in there now, I might give it another shot...just need 40- and 50-MHz
oscillators to give 10 and 12.5 MHz operation another shot.

_/_
/ v \ Scott Alfter (remove the obvious to send mail)
(IIGS( http://alfter.us/ Top-posting!
\_^_/ rm -rf /bin/laden >What's the most annoying thing on Usenet?

Polymorph

scott wrote:
> In article <C31BF953.4D3D%bjjlyates@bellsouth.net>,
> winston19842005 <bjjlyates@bellsouth.net> wrote:

<snip>

>
> I used 12-ns SRAM for both tag RAM and cache on mine, so it has the
narrow
> chips all across. Then again, I think I paid nowhere near $12 per
chip for
> it...JDR isn't exactly the cheapest place to buy this stuff.
>
> I've had trouble in the past getting it to run reliably beyond 8 MHz,
> though, even with a 14-MHz processor and with whatever 74Fxx parts are
> supposed to be replaced with 74ACTxx. With the upgraded power supply
that's
> in there now, I might give it another shot...just need 40- and 50-MHz
> oscillators to give 10 and 12.5 MHz operation another shot.


Scott,

I read in a couple of places that in order for the upgrade to work, the
DATA SRAMs needed to be considerably *slower* than the TAG SRAMs. Now I
have no idea why this is, but it might be your problem? This is exactly
why the hypercard stack specifically says to use 70ns SRAMs for the
DATA. It also allows for an easier upgrade as .6" chips are still
available at this speed. It also says that 12.5Mhz should be obtainable
for just about everyone using this method. YMMV with faster speeds
however. When I get some more crystals, I'll try pushing mine board a
bit faster and see what I can manage.

The other thing I should point out (as its a bit misleading), the prices
I have listed on my web site is the total cost for all of a particular
part. So the US$11.98 that I've listed is for *both* the 12ns SRAMs. I
probably should put a note on my web site indicating this - my bad.
There may be other places cheaper, but JDR was previously mentioned and
they had just about everything I needed (which is important when
shipping to Australia as you want to minimise the shipping cost).

cheers,
-p