Re: Need help with Zip

[Rubywand <rubywand@swbell.net>]

JB writes ...
>
> ....
> >> It's supposed to have 64k.  It will work for a few minutes but inevitably
> >> it crashes.  When it's working the zip CDA shows 12.5mhz with 64k cache.
> ....
> 
> Unfortunately, It will still crash with a big fan blowing right on the zip
> with the lid off....  I tried to feel around the zip and didn't notice any
> extremely hot chips.  It crashes almost immediately when doing things like
> accessing the CDA's and running platinum paint.
> 
> my config:
> 
> Rom 3 GS
> 
> 4MB Q-Ram card
> 200MB Focus Drive (slot 7)
> Superdrive card (slot 5)
> Zip GSX (slot 4)
> Soundmeister stereo card (slot 2)
> ....


     The usual recommendation when an accelerator upgrade leads to
crashes is to fatten the Power Supply +5, +12 leads and one GND lead in
order to eliminate a major source of noise glitches. The more
power-sucking stuff you have plugged into your Slots, the more important
the PS mod.

     Your system does not seem to be terribly heavily loaded; so, the PS
mod is not an obvious recommendation. Plus, as a ROM-03, there should be
less of a problem with Slot bus noise glitches.

     In your recent post, you seem to be saying that your system bombs
fairly soon after startup when typical bomb checks (e.g. accessing the
Desk Accs Menu) are tried even with a fan blowing air across the Zip-GSx
12.5MHz/64k board. This makes over-heating seem less likely as the
source of your problems.

     If you are sure your Zip-GSx runs like a champ at 16k and continues
to bomb at 64k the problem may be noise or some problem with one or more
RAM IC's on the board or some problem with DIP switch settings.

     One quick check for noise glitching is to reduce the power drain by
pulling some moderate power user such as the Superdrive card. If crashes
are reduced, PS lead noise becomes a better suspect. (But, if crashes
continue as before, noise is not eliminated as a possible problem.) 


     Also, is there some special reason for putting your Zip-GSx in Slot
4? It can run okay in Slot 3 and you will slightly reduce noise because
Slot 3 is closer to the PS connector. (Slot 3's Slots setting remains at
"Built-in Text Display".)


     Regarding RAM, in a 1992 accelerator upgrade article, John Link
says that his Zip-GS worked fine at 12.5MHz/32k with the original 45ns
RAM. On the other hand, Scott G indicates a need for faster RAM at
14MHz. 12.5MHz is not a lot slower than 14MHz. It may be that, on some
boards, faster RAM is necessary for reliable operation at 12.5MHz.


     On your board, do you have the 14MHz 65C816 installed? What RAM
chips do you have in each TAG and DATA socket? Who supplied your RAM
chips and was any particular speed (e.g. 45ns, 35ns, etc.) specified?


     It may help to know that at least some Zip-GS boards seem to have
DIP switches which do not always set correctly when flipped. Try undoing
and re-doing each DIP switch. When changing a DIP switch, a slow, mushy
press may fail to achieve a complete make or break. It is best to use a
pointy tool and 'snap' the switch into position. (While you're checking
your board, it won't hurt to scooch up and re-socket each RAM IC to
assure good contacts. Also check for bent pins on the RAM chips.)   

 

Rubywand