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Quadra 840AV mobo

sunder

Well-known member
For a long time, maybe since 1995 I had a Quadra 840AV motherboard and power supply in the closet. It came from a discarded, stripped machine at work that was being thrown out, and had it's CDROM and floppy drive stripped. Was just been sitting there all this time, and I had forgotten about it.

After trying to power on my old IIsi which probably has a bad power supply, I was scrounging around for a 68K Mac to play with and remembered that board. I couldn't turn it on for the last two days, even after changing the PRAM battery. Today, I tried it again and this time reset the PRAM with option+apple+p+r and it just worked!

I hooked up the old hard drive from the IIsi directly to the motherboard and she booted up! Hope it's a stable motherboard.

Now, I'll have to build a nice hackintosh case for it. :cool: Sorry for the poor quality photos, they're from my crappy berry.

840av on floor.jpg

Woot, the one single SIMM it has is a big one! Either that or ram doubler is lying to me.

840av about.jpg

 

Bunsen

Admin-Witchfinder-General
Woot, the one single SIMM it has is a big one! Either that or ram doubler is lying to me.
The figure for "Built-in memory" is the actual physical RAM; the one for "Total memory" is that plus the disk-based simulated RAM created by RAM Doubler.

While you have it out, would you be able to do me a huge favour (which you might be doing anyway, as you're recasing it) and measure and post the exact dimensions of the board? Metric preferred, but I'll take what you've got :D

 

sunder

Well-known member
840AV board is 29cm front (power switch)-to-back (ports), by 31cm left to right. Was going to say wide x deep, but it depends on how you hold it. :)

Unfortunately the power supply is oddly shaped, and it doesn't quite fit in right inside the CD Jukebox case. Well it would, but then the fan would be pointing at the wall, or the connectors would. Oh well, I'll have to find some other enclosure or raise the top or something.

 

Bunsen

Admin-Witchfinder-General
Thanks for that. Definitely won't fit where I was hoping it would :/

Unfortunately the power supply is oddly shaped, and it doesn't quite fit in right inside the CD Jukebox case.
If you made an extension cable for the power connector, would that help?

 

sunder

Well-known member
Nah, I'd have to cut holes in the PSU and move the drive cables out of the way to make it work - maybe.

Problem is this, the PS is rectangular, so it has 6 sides. One side has the A/C input, another side has the fan, another side has the drive cables, another side has the motherboard connector. The only way to get it to physically fit, is if the fan faces the wall of the enclosure, which would cause overheating to the PS. If I cut a hole in the case for the fan. then the mobo overheats.

Other ways of positioning include the A/C inputs down or to the side, which therefore are also blocked. :)

The only way to get it so that the fan faces the mobo and the A/C face the back makes the top of the case stick vertically upwards by about 2-3 inches, so it won't close.

If I take the PSU apart and cut holes/reroute some of the plugs, it might work. Either that, or as someone already mentioned, replacing the PSU with a PC PSU.

BTW: I've found a place that still sells memory and VRAM for this machine, and it's fairly inexpensive: http://www.memoryx.net/quadra840av.html

 

Bunsen

Admin-Witchfinder-General
Well, they say they do, anyway. Let us know what transpires if you decide to order.

 
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