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

[marvinmiller@hotmail.com (Marvin Miller)]

YES, I've tried my accelerator at 7 Mhz! Have you tried downgrading
your accelerators to 7Mhz? ;-o

In as far as de-soldering the 74F00 chip and installing a new one -
There's a good electronic repair shop in town who do nothing but
soldering all day. I'm sure they can make it so that you can't tell
anyone was in there. For them, it's probably a pretty simple operation
- looks like it to me anyway, lots of access etc. I haven't heard yet
WHY this needs to be done. Did you perform this upgrade Wayne?

Seriously though, I ran into some really old ZIP txt files (1992 era)
and they were mentioning all over the place that it's no problem to
get 15Mhz out of it with the complete mods.

The way I see it, plug an play is 75% of it. A 5 second trip to the
electronic shop is pretty easy, the hardest and most annoying aspect
seems to be finding the correct part numbers (current) for the right
products. Being I'm in a more 'remote' region of Canada and seem to
have no access to these parts - they will likely have to come from the
USA. As such, I want to get it right the first time before paying
exchange, duty, pst, gst and of course, shipping fees.

Best;
Marvin

On Sat, 11 Nov 2000 17:40:45 -0800, Wayne Stewart
<waynes@intergate.bc.ca> wrote:

>
>
>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
>