Getting a Mirror Door working again (help!)

[part12studios]

Hi everyone, so I've been patiently keeping an eye out for a MDD 1.25ghz model and one came along at a bargain, but not 100%, but hoping there is hope.

I made this video of it.  https://youtu.be/QkFI59HOfiQ

TL;DR

Unit powers up.. no chime.. no apple.   fans start out low.. then after a few seconds kicks into high gear and that's it. 

I tried a PRAM reset, but I think this doesn't even get to that point to respond to the keypresses. 

It had a dead (but not leaking) cmos battery.  I have a fresh one on order. 

Other than that behavior it seems like everything is pretty much clean and treated well. 


Thanks!
Caleb

[FBz]

1GHz MDD UNI processor
(nice shiny paste on chip)

1. Baked?

2. Heatsink clips too loose?

3. Both?

4. Other (like sand in the vaseline)?

D. All the above?

[MacTron]

Where is the cpu?
It seems as the thermal paste was applied after a total cpu annihilation.

[part12studios]

I'm going to be spending some time this weekend completely cleaning it of all residual paste and reapply. 

I did a first pass re-application after a modest, but not 100% cleaning and that didn't help.  Without knowing it's completely clean and re-applied it could be some self protection going on continuing to keep it from moving past the initial self test.

The battery is a variable, but I'm not expecting that to really fix it, but will be nice to know it's getting the proper voltage for the battery. 

The bigger question that FBz questioned is IF it's the CPU, how much other burnt out stuff is in there.  will replacing the cpu alone fix anything or are there deeper issues?


A few other things that were done. 

1. swapped out the GPU with another one from a sawtooth.  The MDD GPU booted up and worked with the sawtooth so overall I'm ruling out that the GPU was an issue. 

2. Removed the ram as well to insure there wasn't some kind of memory problem.  with or without any particular chips or no chips had no effect to get this unit to chime. 

[MacTron]

Once the chip is clean, Your should read most of the letters on the chip surface.

1. swapped out the GPU with another one from a sawtooth.  The MDD GPU booted up and worked with the sawtooth so overall I'm ruling out that the GPU was an issue. 

Did your MDD really boot with a Sawtooth CPU module? 

[FBz]

Did your MDD really boot with a Sawtooth CPU module? 

GPU (graphic) - not CPU.
Often confuses me as well.

And he can read most of the letters on his chip after cleaning.


Concern was that not all of previous paste (or other obstruction)
had been removed and that might have kept heatsink from proper
seating / mating. Accustomed to seeing a smooth, even spread of
the paste from sufficient downward pressure via the heatsink clips.

Even after fresh application of paste and the heatsink -
(then removal) the paste should appear more evenly spread.
Unlike the uneven “blobs and voids” look in his previous pic.

Haven’t seen the backside yet, where chip mounts to board.
(To check for evidence of overheat / possible failure.)

Hadn’t considered that someone might have applied paste
after the total annihilation of the CPU… & before purchase.

Awaiting more info and close inspection of daughter card.

[part12studios]

I will give it a good workover tomorrow and report back with some close up pics of the board above and below once fully cleaned.

Thanks for everyone's insight / help.  I really hope I can bring this baby back. 

Thanks,
Caleb

[DieHard]

I will give it a good workover tomorrow and report back with some close up pics of the board above and below once fully cleaned.

I am afraid, in the end, this will be like giving a guy that already died of a heart attack, a triple bypass; the fact that it did not display video will never be cured by arctic silver... if it displayed video and then shut off after 5 minuted, then you got a heat shutdown issue and it's arctic to the rescue.

So it's possible the damage is already done, but a good inspection (as suggested) is in order. look for board dark areas of discoloration, this is heat damage.

I might also go the arctic route as a per-cursor since it needs it badly, think of it like a "at least I won't damage the CPU if it's still good" measure, then check /clean RAM, inspect logic board, etc.  If the RAM is good and you already checked the graphics card, your down to a bad Logic board or CPU daughterboard

[part12studios]

if this was damaged due to heat, is it likely this daughter board would be where the damage is contained?  i am just wondering if i were to replace the entire daughter (CPU) board with another 1.25ghz board, would it most likely fix things? 

I'll report back today with pics of the system. 

Also as far as I can tell is a single core 1.25ghz..   I saw this and if this is a 1:1 with what I have, seems like a fair price to bring this baby back to life

https://www.ebay.com/itm/223816313647?hash=item341c7deb2f:g:OEoAAOSwE0JY~iwT


Thanks!
Caleb

[DieHard]

Diehard:

If the RAM is good and you already checked the graphics card, your down to a bad Logic board or CPU daughterboard

Part12studios:

I am just wondering if i were to replace the entire daughter (CPU) board with another 1.25ghz board, would it most likely fix things?

A- 50% chance of success

[part12studios]

Got it.   Dang..  but yea makes sense. 

How would you suggest I rule out one or the other beyond looking for any signs of damage?  is there some other indication of trouble?  or means of troubleshooting? 


One other question..  does anyone here know how to remove the daughter board?   Do i need to remove the entire board to get to screws holding it in on the other side?  Seems likely to be the case
 

I'm asking before I go tearing the whole thing apart. 

[part12studios]

Also, while i know the cpu daughterboard is very specific and likely a nice 1:1 replacement..  but are logic boards particular?  are there certain model options for 1.25ghz MDD?  or is it a very specific logic board that works with it? 

[DieHard]

Many of the answers you seek grasshopper may be found in the ancient texts found here...

http://macos9lives.com/smforum/index.php/topic,3207.0.html

[part12studios]

ah fantastic!  Thanks for this.  I have found these style manuals super helpful for the Quadra 650 I had to work on and a few powerbooks I was unsuccessful in fixing..  but not the manuals fault!

[part12studios]

Sorry about the silence, my workbench got really cluttered juggling a few projects I didn't want doing more damage to it with things around it..  now things are more sane

ok so I removed the card and everything looks ok.  no clear signs of something zorched..  when i hit the power button with the daughter board removed it only lights up and immediately fades out. 

I've ordered a higher resolution usb microscope to take some up close pics and really see with more clarity.  the one i have is 640x400 and not terrible, but it's not going to see anything meaningful.

Once I get the new microscope i hope to be able to better inspect the various parts for any signs of damage.

I'm feeling like it's the daughterboard.  However, I'm not sure how i can really isolate them without just swapping out parts.

[part12studios]

Hey everyone, just wanted to report back and first of all say thank you for your insight and encouragement!   Now for the good news.  So I saw someone selling the 1.25ghz single core daughterboard for $35 from overseas including shipping seemed like a fair risk seeing that I wouldn't find one cheaper and even if this didn't fix it, I could have a spare and then look to replace the logic board next. 

Welp, good news is that it was the issue.  Once I replaced the daughterboard CPU, the system booted up and all is well!  I've put OS9 and Leopard on it.  I put fresh thermal paste and looks good.  Which reminds me I still need to do this for my Quicksilver. 

[DieHard]

Diehard:

If the RAM is good and you already checked the graphics card, your down to a bad Logic board or CPU daughterboard

Part12studios:

I am just wondering if i were to replace the entire daughter (CPU) board with another 1.25ghz board, would it most likely fix things?

A- 50% chance of success

Let me readjust that to 100%

[part12studios]

lol    yes awesome.   ordered 2gb of ram for it..     now looking at what bootable pci controller cards might be available to buy that would use PCI 64bit slot to it's fullest potential and work under OS9.   I'm working through this thread tonight

http://macos9lives.com/smforum/index.php/topic,306.0.html