MDD CODES

[Andre Solomko]

Anyone remembers what means 4 times blinking on sturtup? D a mn it have 2mdd and both refuse to start ttod a y.....

[GaryN]

4 times is very, very unusual.
4 times on two different machines at once would make me guess somebody's been messing around trying to flash the ROM or similar.
(assuming they're both doing the same thing - you didn't actually say that)
If you haven't already, remove and reseat the RAM - probably NOT the problem, but quick and easy to try.

For the record, these are called POST (Power On Self Test) codes.

1 = No RAM installed
2 = Incompatible RAM type
3 = No good banks (MDD needs at least one good SIMM to start)
4 = No good boot images in the boot ROM (and/or bad sys config block)
5 = Processor bad or unusable

So, #4 indicates a ROM issue which almost never happens except as a result of trying to modify the boot somehow.
If that's what happened, you have bigger problems than I know what to do with.

Just because you should, and sometimes it works, try resetting the PMU.

1. Unplug everything - I mean everything.
2. Open the side, find the little red PMU button in the corner of the motherboard in front.
3. Press it once only for a second
4. Plug all back in.
5. Cross fingers.
6. Try to start again.

If that all fails, you next move to testing the PSU

[Andre Solomko]

Now.  It just pushing ventilators on full speed and no go. Gary thank you your table is about beeps not flashing. Flashing exeeds by one meaning 4=3 so it complains about memory. Etc. No memory would be 1 beep 2 flashes.but as i said its not an issue. Now no start and ventilators on at full speed.on . damn on 2Machines !!!!  Aand yes i have tried all cudo shamanism and swapping and so on.... just wonder if anyone had same symptoms

[darthnVader]

It's possible you have a corrupt NVRAM interfering with the boot rom.

I've never owned a MDD, but if it's like other G4's you can load the default NVRAM settings by holding the power button, and keep holding it. You'll hear a programers tone, followed by a boot chime, keep holding and the system should boot to Open Firmware with the defaults loaded, where you can reset the nvram.

This works even when Command+Opt+P+R won't.

It may not work for you, if you have a hardware problem, but it's worth a shot.

[Andre Solomko]

Thanks. It didnt work. There is a hardware problem on both patients. But what  and why the same night? Last question is rythoric.....

[darthnVader]

Thanks. It didnt work. There is a hardware problem on both patients. But what  and why the same night? Last question is rythoric.....

Could be you had a power spike that killed something in your PSU's and they are not properly powering the logic boards. That would explain why both died at the same time, in the same way.

Logic boards for MDD are not hard to find, or expensive, so it maybe worth replacing one to see if that fixes the issue, before putting the money or time into the PSU's.

MDD PSU were flaky to put it kindly, but there is a thread around here somewhere with some info on trying to resurrect them.

MDD PSU's can be expensive, you'll likely find a cheaper complete MDD than the price some people want for working PSU's.

[Andre Solomko]

Thanx again. Definitely its a logic board probllem. I exclude a powerspike theory becaause they died in a different way.. psu always was crappy
To start with. I didnt bother with resurrection. Sometimes replacing of caps will do a trick but its very annoying. And not for long. Next your regulators will die. So both of my. Mdd have ATX psu in a great condition.
And they were working flawlessly. Get a logic board here not easy task.