MDD Memory Message

[madalynmcworm]

Hi all!

I booted my MDD today for the first time in a while and it was idling fine. I went into USB MOUSE and it hung up. When I tried to Force Quit, there was no button on the force quit dialog and I had to hard power it off.

When it rebooted, it gave me a cryptic message about there being a memory problem and contacting support.
I rebooted it, same thing.

I attempted to boot AHT 1.2.7 and it started and would fail out to the rom with a boot or shut-down. Booting just sat with a folder with a ?
I attempted a second boot of AHT with a slower burn speed 10x. Back to open rom. Both times had the same memory error.
https://discussions.apple.com/thread/1276655?start=0&tstart=0 has the same error I received. "invalid memory access at %SRR0: 00034870 %SRR1: 00003030"

Booting the tech tools 257 disk also did not work. It did what I assume was start to boot, with a mac os 9.2 and then the mouse icon was a bomb.

I installed the tech tools from mac tron recovery disk and it says it passes the memory if I don't do the long march. Long March hung up after about an hour? The big system test passed all tests, then when displaying results hung up.

Thoughts?

[madalynmcworm]

I'll add that I do not recall looking at the circling arrows on TechTool Pro 3.0.9, and it may have been running a ram test and not actually hung up. I notice that the time does not update while it is running the ram test, and I assumed it to be hung as it was an hour later than the time on the mac claimed. I just watched it take 20+ minutes for it to do a test and during that period, the time also did not update.

I also notice, I simply tried to boot the AHT from here. I'm thinking that might be wrong. I have other cards, etc in it.

[GaryN]

I think you may have skipped over the first practical troubleshooting step here. You keep getting memory error messages.
The first step is to pull and replace the RAM modules. In many desktops, and especially in the MDD where they're right next to the CPU, the repeated heating and cooling causes expansion and contraction of the chip modules in the sockets and even the chips themselves on the cards - especially the first one. So you:

Pull them all and reseat them and see what happens. If that doesn't help…
Pull TWO of them and reboot. If that works, then…
       Replace the pulled ones one at a time until you get to one that brings the problem back - THAT module is bad
If that doesn't help…
   Put them back and pull the other two. If that works, then…
       Replace the pulled ones one at a time until you get to one that brings the problem back - THAT module is bad

As you can see, the objective is to deduce the bad module by testing in pairs until process of elimination finds a bad one.
If none of this works, you move on to other tests.
…And you're correct about AHT. You need to pull all PCI cards and Firewire / USB external stuff before testing.

You always do this first, before you run RAM tests and such because it's perfectly possible (and common) for a chip to pass a test and then fail again the next day.

[madalynmcworm]

Yes, I agree I should have started pulling ram sticks. I didn't after it booted with no trouble. I thought maybe I had jiggled the airport card loose.

It again booted with memory issues. I pulled all the RAM. Been booting into AHT.
1 stick passes just fine.

I moved 2 sticks around, they are mismatched, but appear to be solid.
.
I have some PC3200U sticks.
I could just buy 3 new 512MB sticks.

Thoughts?

Appreciate the help!

[GaryN]

Again, the objective is to positively identify a bad stick by testing in pairs until you have a solid operating machine, then test the other pair, and so on. If you don't have the time or patience for that (because it does take a while) you can certainly shotgun the RAM by replacing all four with new, known to be good sticks.

The MDDs were shipped with PC-2700 sticks because of the MDD's 167Mhz bus. You can use PC-3200 sticks but they won't run any faster.
One more time: The important thing here is they're known to be good. Stick chips in there that you have laying around that are of the "Well, I guess they're good" variety and you might get a good result - but if you don't, you still won't know for sure what's going on and you'll have to start all over again.

…and yes, you can certainly buy new RAM and still get a brand new defective stick.
To make this procedure work, you have to buy quality stock from a very reputable dealer so that the odds are excellent that they're good.
Chinese mystery chips from ebay do not qualify.

[madalynmcworm]

Thanks for the follow up!

RAM in machine was as follows: PC3200 512MB stick (cannot tell brand), PC2700 512MB stick (different manufacturer, cannot remember brand), PC3200 512MB CORSAIR x2.

Earlier, when checking, my method was pull all ram and re-seat the matching pair of corsair, and booted AHT. AHT reported that slot 1 was unoccupied and gave an error. Tried to re-seat, same results. Swapped, problem reversed. Slot 2 was "empty". Removed slot 1. Replaced slot 1 ram stick with PC3200 unknown, AHT refused to boot, memory error. Removed slot 2 corsair, replaced with PC2700, same problem. Swapped, same memory error. Removed slot 2, leaving only PC3200. Booted fine, past AHT test. Put it the "good" corsair in slot 2. Booted, passed tests.

I should have been more clear with swapping them around from previous post. I will be more clear in future posts

Typically, ram I have laying around was mem checked before static bagged, usually in memtester for several burn in passes. It is why I would consider it.

I'm done buying cheap Chinese anything. It usually isn't worth it in the long run. I believe I found reputable source of ram for the system, new. I'm planning to just buy that tomorrow. Good to know I need 4 sticks.

Appreciate the help, GaryN. I really do.

[GaryN]

Sounds like you're succeeding. Carry on!

[madalynmcworm]

Purchased 4x512MB sticks from at $8 a stick for Samsung ram. New. Seemingly working great.

[GaryN]

Purchased 4x512MB sticks from at $8 a stick for Samsung ram. New. Seemingly working great.

There you go. Sometimes the simplest way is the simplest way!