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

[Rubywand <rubywand@swbell.net>]

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?


> 
> 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.


 
> *** Going from .600 --> .300 on the Cache Chips ***
> 
> It looks like I've found what I needed here. From the DigiKey catalog
> what's needed is (4) A504-ND Goes from .600 --> .300 using 28 Pin DIPS
> 
> *** Oscillators ***
> 
> Listings from DigiKey show both;
> CMOS TTL Full Size &
> Full Size
> 
> Are these interchangeable? IE: Does the CMOS spec make it different?

     If the pin spacing for each is standard "full size", the clock modules
should be interchangeable for your application. The oscillators on page 144
of catalog P004 (CTS Reeves MX045) look pretty good. You want a "standard
output" model.

     It's a good idea to get two or three different frequencies-- like 36MHz
for 9MHz operation, 40MHz for 10MHz, 48MHz for 12MHz, ... . This lets you
experiment with operation at different speeds.


> 
> Once I get through this and have the right parts, I'll post a part
> number list for all the items needed from DigiKey and whathaveyou, so
> someone can just order the stuff without doing this leg work. I
> couldn't find the ness. info in the FAQ's. To me it seems you still
> have to have a pretty decent underestanding of electronics to make iot
> from the the FAQ to ordering.
> 
 ....

     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'?  

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

http://home.swbell.net/rubywand/Csa2POWER.html#007 .



Rubywand