MDD is toast

[w3sl33]

Last week MDD 1.25DP stopped recognizing 1GB Ram. AHT said slots 1 and 2 are bad. Rebooted and Firewire ports disappeared. AHT stopped working and only boots into open firmware. Took out all the cards. Changed new RAM and slots and different configurations. No change. Checked the power supply and voltage was not correct according to the great tutorial someone posted here not long ago. MOBO is now giving errors in open firmware as well. Only one processor is showing according to the open firmware error codes. MDD was working fine use it everyday for DAW. Now it hesitates and surges when it boots. Anybody know what could have caused all this suddenly to go wrong?

[Bolkonskij]

I have the same model (albeit with a Sonnet upgrade). The RAM slots are known to be a bit picky / quirky, one in particular but I can't recall which one. (I got to know after mine died some years ago and found others online with the same problem)

Other than that, i found it to be very reliable and a true workhorse. That is, until ... my PSU died last year! Suddenly my MDD started to act weird. Sudden total freezes (no MacsBug) to outright powering off the machine in mid-use.

If you say you checked the PSU and it gives odd numbers my best bet would be looking for a PSU replacement. After I replaced mine with a spare one I had it booting up and working fine ever since! Given these PSUs push towards their 20 years of service, you'll eventually have to replace it anyway. At least that is how I see it ...

[w3sl33]

I was thinking of re-capping it myself. Before I open it up I was looking for a schematic for the ACbel if anyone knows a source?
Otherwise I got to wait until I can afford to replace it. Great computer model when it worked though.

[FBz]

Check this…  http://macos9lives.com/smforum/index.php/topic,4088.msg28011.html#msg28011 and read through all posts under the entire Topic.

And Double - Triple check and note each individual capacitor in the list, against those that you actually pull from your PSU and then order accordingly. Yours may vary slightly…

Good luck and have mucho fun.