Broken Mac Accelerator

Don THX1138 at
Sat Sep 9 00:24:59 CDT 2006

Teo Zenios wrote:
> My latest acquisition came in today, a Mac IIci, that I wanted to use as an OS 6.08 machine with a Daystar Turbo 040 (68040/33) accelerator. Anyway after cleaning up the system and installing the OS I put the card in and loaded the drivers and all was fine (very fast booting). After about 15 minutes I had to reboot for driver update and the system would just bomb during boot (about where the control panel for the Daystar card would want to load). I took the card out and notice there was a capacitor missing on the back with a nasty looking black burn mark. So I started looking around inside for the burn metal part and notice I did not smell or see smoke or little capacitor parts (its a surface mount with no numbers on it). Doing a little digging in my picture archive I verified that the card which I have never used before (which is why I wanted a IIci since it works in that model) was sent to me in this condition.
> So what I want to know is how the thing functioned at all without the cap (burnt carbon acted as a capacitor in some way)? and what caused it to stop working.
> If anybody have an original Daystar Turbo 040 33Mhz card with the cache on a separate board could you let me know (if possible) what value C54 s supposed to be? The cap looks to be tied into one or two legs of the oscillator chip that controls the CPU (Ecliptek EC1100 16.667Mhz 93-10).
> I kind of want this working again since it will be a long time before I find another one at a great price.

Not sure of what you have (nor what *I* have!)  :<
But, I found a couple of Daystar cards in my Mac pile.
Some are 030.  I found an 040 that claims to be a "Turbo 040"
(written in the solder side foil layer on the corner of the
card furthest from the 040).  The 040 seems to be a 33MHz part
so I will *assume* this is at least SIMILAR to what you're looking

However, last used C seems to be C49 -- located on the solder
side between the CPU and the DIN connector.  <frown>  Perhaps
a different revision?

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