Re: ZipGSx Upgrade Questions (I've read the FAQ's)

[Wayne Stewart <waynes@intergate.bc.ca>]

Rubywand wrote:

> Marvin Miller writes ...
> >
> > Hi Folks;
> >
> > I'm trying to assemble a lit of the items & part numbers of components
> > needed to upgrade my Zip GSx 1.02.
> >
> > I've read the FAQ's and searched the newsgroups to obtain all info
> > regarded to this process and I still have some questions.
> >
> > ** Replacing the 74F00 chip with the 74HC00 one **
>
>      Where did you find this in the FAQs?

It's in the old Faqs that Nathan Mates had maintained

> >
> > I have found that it's a 14 pin DIP. Doing a search on Digikey and
> > narrowing it down to one manufacturer (FairChild) and Package to
> > 14-DIP still brings up a numerous possibilities.
> >
> > The 74HC00 questions seem to arise out of the IC Function and Number
> > of Circuits variables. Can anyone help to isolate the _exact_ one I
> > need?
> >
> > Some of the possibilities IC Functions are;
> >
> > 2 Input NAND Gate, Inverter, 2 input AND Gate, Buffer, Inverting
> > Schmitt Trigger, 8-bit Shift Register, 2 Input OR Gate, D Type Flip
> > Flop, 2 Input Exclusive OR Gate, 2 Input NOR Gate, Binary Counter (4
> > bit), Bilateral Switch etc.
> >
> > Some of the possibilities on Number of Circuits can be;
> >
> > Quad, Hex, Octal, Dual etc.
> >
>
>      The 74F00 and 74HC00 are variants of the old 7400-- the IC has four
> 2-input NAND gates.
>
>      Do not know why anyone would replace a 74F00 with a 74HC00 on an
> accelerator board. The 74F00 is a much faster gate than the 74HC00. You would
> think that when speeding up a board you would, if anything, want to move to
> faster gates. Suggest you leave your 74F00 where it is until whoever made the
> recommendation explains it.

I heard the explanation about why a slower chip helped there about 4 or 5 years
ago but don't recall the details. However I've sped up several ZipGSs and always

topped out at 12 or 12.5mhz till I replaced the 74F00 with a 74HC00.
I'd strongly suggest taking the ZipGS as far as you can with plug-in parts
which'll
likely be about 12mhz, then give it some thought.
Accelerators are getting a bit hard to find.
Most people can easily tell the difference between a 7 and 12mhz IIgs but the
difference between 12 & 15 isn't all that noticeable.
Every now and then someone posts a message "I tried speeding up my accelerator
and
now it won't work" I'd suspect 10 times as many people did that and never said
anything..
If you are going to so more than swapping socketed parts then I'd strongly
suggest doing
one part at a time and seeing if it still works. Makes it easier to troubleshoot
if problems
arise
If you need to remove the ZipGS from you IIgs at any time I'd suggest unplugging
the
cable from the card rather that from the CPU socket. The end that plugs into the
CPU
socket is more than a little delicate.


<snip>

>
>      Guess that's true for something like an accelerator upgrade project.
>
>      By the way, (don't recall if you mentioned this) have you tried out your
> accelerator 'as is'?

A very good question indeed.

>      Something else: be sure to check out the power supply lead and
> motherboard mods discussed in the Power Supply and Cooling FAQs at ...


    Wayne