Flashing Power Light - Mac Pro not booting

[MentalVizion]

I had a G5 that exhibited the flashing light problem. I forget the specifics, but all the other indications pointed to a bad PSU. At the time, the machine was due for an upgrade so I never had it repaired to confirm it.

If you go the RAM route and that doesn't fix it, I would try the power supply next.

I also think the PSU isn't quite as innocent as it seems.
It's a Bi*ch to remove though IMO.

On the other hand, in the topics I read, where the PSU was the cause, people always seemed to get the light and then it just shuts down (like plugging the power cord). Mine doesn't do that.

What you need is another similar machine to swap trays with

I really don't have the money for that
I will wait the few days until I get the RAM, and if that doesn't help aswell, I'm pretty damn sure it's the board.

 

[MentalVizion]

A little update from my side:

Took out the PSU and cleaned it. Some dust came out of it but still no change.
Then I cut my finger on the alu case and bleeded into the Mac.

After some further "investigation" I also came to the conclusion that it probably isn't the logic board or PSU causing problems.
Read the repair manual for my model, and PSU and Logic board seem to be alright.

The OVTMP CPUA and OVTMP CPUB flash red shortly when plugging in/out the power cord. The 5V STBY is illumintaing amber-like, and the PSU PWROK is lighting up green. As written in the manual.

Just have to wait a few days to get my RAM. But it's so hard to have it stand right next to me just waiting to get fixed

 

[MacVidCards]

I really don't have the money for that
I will wait the few days until I get the RAM, and if that doesn't help aswell, I'm pretty damn sure it's the board.

You need a friend with one.

Or even just rent one. I did a shoot in Indianapolis a couple years back and was able to rent a MP for peanuts.

You could have the answers to all of this in MINUTES. No guesswork or throwing parts at it.

 

[MentalVizion]

I'm located in Austria.
My brothers getting a 3,1 on Saturday, but until then I should also have my RAM here. Also it has different DIMMS if I remember correctly.

 

[DanielCoffey]

You would need to rent a 4,1 if you wanted to swap parts...the incoming 3,1 will not help you diagnose this.

I would be surprised if the rental company would like you swapping parts so you better be damned good at putting it back together neatly.

 

[OS6-OSX]

After seeing dust in the PSU did you spray the rest of the MP? Did you spray the slots of the memory risers were the feet of the ram contact the board?

 

[MentalVizion]

After seeing dust in the PSU did you spray the rest of the MP? Did you spray the slots of the memory risers were the feet of the ram contact the board?

Already cleaned the whole Mac, like twice

 

[iBug2]

If the PSU was dead or faulty, nothing would happen when you hit the power button. If it's blinking constantly it's 99% RAM like you said. Try one by one each RAM module you have, but follow the rules. Install only 2 DIMM's one on the top risers 1st slot, one on the bottom risers 1st slot. Then go 1 by one through your DIMM's. If none of them work, then either all your memory is dead or it's something else. But if the logic board is faulty you'll get some LED's on the logic board lighting up when you try to boot.

 

[MentalVizion]

If the PSU was dead or faulty, nothing would happen when you hit the power button. If it's blinking constantly it's 99% RAM like you said. Try one by one each RAM module you have, but follow the rules. Install only 2 DIMM's one on the top risers 1st slot, one on the bottom risers 1st slot. Then go 1 by one through your DIMM's. If none of them work, then either all your memory is dead or it's something else. But if the logic board is faulty you'll get some LED's on the logic board lighting up when you try to boot.

I'm going to try it again, but there's not much hope left.
One thing though: You said the 1st slot of the bottom riser, and the 1st slot of the top riser. Shouldn't I use (if only using 2 DIMMs) Slot 1&2 on the bottom riser? Atleast thats what I read (and saw) for the 2009 models.

Thanks though!

 

[iBug2]

I'm going to try it again, but there's not much hope left.
One thing though: You said the 1st slot of the bottom riser, and the 1st slot of the top riser. Shouldn't I use (if only using 2 DIMMs) Slot 1&2 on the bottom riser? Atleast thats what I read (and saw) for the 2009 models.

Thanks though!

Ah sorry, you have the 2009 model, I was talking about the 2008 one.

 

[DanielCoffey]

I'm going to try it again, but there's not much hope left.
One thing though: You said the 1st slot of the bottom riser, and the 1st slot of the top riser. Shouldn't I use (if only using 2 DIMMs) Slot 1&2 on the bottom riser? Atleast thats what I read (and saw) for the 2009 models.

Thanks though!

Here is the official Apple advice for the 8-core 2009 from http://support.apple.com/kb/HT4433?viewlocale=en_US&locale=en_US#3...

You should install FB-DIMMs in matched pairs of equal size and equal specification. Use the table below and the instructions that follow as guidelines for DIMM placement.

If you have Install
Two DIMMs (standard configuration) One on the top memory card and one on the bottom card
Four DIMMs One pair on the top memory card and one pair on the bottom card
Six DIMMs Two pairs on the top memory card and one pair on the bottom card
Eight DIMMs Two pairs on the top memory card and two pairs on the bottom card

 

[MentalVizion]

Yea, thats the way I tried all of them.
Hope the new one is here tomorrow

 

[OS6-OSX]

What a cliff hanger!

 

[MentalVizion]

What a cliff hanger!

Indeed!

 

[MentalVizion]

Bad news.

Got the RAM today and still no change
Also added some slight contact spray on the dimms, also didn't help.

Starting to despair...

EDIT: After reading VERY briefly through the repair manual again, I found out these are the only components that possibly can cause this issue:

Bad RAM
Bad CPU A
No Connection between Backplane and Processor board

I now doubt that the RAM is still the cause of all this.
I already swapped out the two installed CPU's, and still no difference. So either both of them are dead, it is not the CPU's fault, or probably what is the case: no connection, or maybe even dead processor board.

Do you guys have any more ideas? I'm definately not giving up yet

EDIT#2: Followed a step-by-step guide in the repair manual, and everything went fine until I had to mount a CPU and RAM. There it started blinking again. I also found some bent pins on the CPU B socket of the processor tray. So I guess/hope everything would be fixed by buying a new CPU tray.

To bad I can't find a single stupid store that would even sell one for the 8 core model. Does anyone of you guys maybe have one for sale, or know of a nice place (that ships to EU) that sells one?

Also nothing on ebay. Just for quad-core models.

 

[mikepj]

Bad news.
EDIT#2: Followed a step-by-step guide in the repair manual, and everything went fine until I had to mount a CPU and RAM. There it started blinking again. I also found some bent pins on the CPU B socket of the processor tray. So I guess/hope everything would be fixed by buying a new CPU tray.

To bad I can't find a single stupid store that would even sell one for the 8 core model. Does anyone of you guys maybe have one for sale, or know of a nice place (that ships to EU) that sells one?

Also nothing on ebay. Just for quad-core models.

Have you tried running with just a single CPU? I believe if this is a Mac Pro 4,1, you can just install a single CPU (as long as it's in slot A) and run it that way. Would give you a clue if it really is a problem with the second processor socket.

Just also make sure you only install memory in the slots near CPU A as well.

 

[MentalVizion]

Have you tried running with just a single CPU? I believe if this is a Mac Pro 4,1, you can just install a single CPU (as long as it's in slot A) and run it that way. Would give you a clue if it really is a problem with the second processor socket.

Just also make sure you only install memory in the slots near CPU A as well.

Yes I already tried that. I was running both, then switched them, then I was only running one of them, and then the other one.

I somewhere read that IF the CPU is faulty, there is a red LED next to it indicating that. I dont have these LED's, so I GUESS they are fine.

Also doubt it is the RAM, as I just got a new one.

So the only thing thats left would be the Processor board. But also, everything works as it should until I have to put in the CPU and RAM.

So weird...

 

[hfg]

Yes I already tried that. I was running both, then switched them, then I was only running one of them, and then the other one.

I somewhere read that IF the CPU is faulty, there is a red LED next to it indicating that. I dont have these LED's, so I GUESS they are fine.

Also doubt it is the RAM, as I just got a new one.

So the only thing thats left would be the Processor board. But also, everything works as it should until I have to put in the CPU and RAM.

So weird...

You have said twice "I just got a new one" when referring to RAM. Just to be sure, you are talking about 1-pair of modules, not just a single one? I believe they have to be installed in pairs, even if you are going to install minimum RAM.

 

[MentalVizion]

You have said twice "I just got a new one" when referring to RAM. Just to be sure, you are talking about 1-pair of modules, not just a single one? I believe they have to be installed in pairs, even if you are going to install minimum RAM.

Got 6 1GB sticks that originally came with this model
I always tried installing them in pairs. But as you can see, didn't work^^

So now I have 6x2GB and 6x1GB to test and play around with.

 

[hfg]

Got 6 1GB sticks that originally came with this model
I always tried installing them in pairs. But as you can see, didn't work^^

So now I have 6x2GB and 6x1GB to test and play around with.

Well ... that should do it ... one way or another!

It is a bit disconcerting that you found bent pins on the CPU socket. Possibly the previous owner had a botched CPU upgrade attempt and didn't tell you? I would carefully examine with a magnifying glass to be sure none of the bent pins are shorting now, although the damage may have been done already.

I would have suggested you remove/insert the CPU tray several times to clean the contacts ... but I suspect you have done that more than a few times already.


-howard

 

[MentalVizion]

Well ... that should do it ... one way or another!

It is a bit disconcerting that you found bent pins on the CPU socket. Possibly the previous owner had a botched CPU upgrade attempt and didn't tell you? I would carefully examine with a magnifying glass to be sure none of the bent pins are shorting now, although the damage may have been done already.

I would have suggested you remove/insert the CPU tray several times to clean the contacts ... but I suspect you have done that more than a few times already.


-howard

I already was able to bend all of them into place again, except for one. I think this one is even fried...

I probably will try to sell it for some money and get a proper working one.

Thanks for the help though, appreciated!

EDIT: Just found a Processor board for the quad core model. Do you guys know if these also work in the 8-core models like mine?

 

[DanielCoffey]

The good think about all this work you have had to do is that by the end of it, you will be a lot more confident about handling and upgrading the MP in the future.

Even though it is frustrating having to spend the money to get the machine working, you have gained the experience.

 

[666sheep]

EDIT: Just found a Processor board for the quad core model. Do you guys know if these also work in the 8-core models like mine?

It will as long it's 4,1 with original firmware.

 

[MentalVizion]

I now ordered the single processor board. If it's not working, I can send it back within a month. I also have 12 months of warranty.

 

[MentalVizion]

Just to let everbody know:
I ended up selling it as I didn't want to spend to much money on it to MAYBE work.