Power Mac G5 won't start.

Hey folks! I have a Power Mac G5 quad core 2.5 that isn't starting up. I'll give you all the info I have so you can help diagnose the problem.


I recieved this computer second hand and it worked great. However, about two years ago it would atart shutting down and the OVERTEMP led would come on. I started running the machine in "reduced" mode, and while not ideal, I was able to at least use the machine. I researched and found out about the issues with the liquid cooling systems and the heat.


Last Friday, and computer shut itself to sleep while I was using it, with the OVERTEMP led again lit. It would not wake up, so I shut it down. Now, when I attempt to restart it, the power goes on, there's no chime, and after about three second the CHECKSTOP led lights, quickly followed by the OVERTEMP led.


I pulled out the LCS, and there was no sign of leakage (I saw pictures of some people who had rice or salt like deposits all over their logic boards. Mine was fine.) I took the LCS apart and flushed the heck out of it with hot water. There was sediment in the radiator, and a lot of clogging in the filters right behind the processors. I cleaned it all out, gave it new coolant, clean hoses, and fresh thermal paste. I put everything back together, but I got the same result at startup.


I also changed the PRAM battery and reset the SMU. Still the same thing.


So that's where I'm at. Does anyone have any ideas, because at this point I'm open to anything. I don't have the money to replace this machine, and a lot of my life is on here, especially the articles my girlfriend writes for the local paper. We don't have a laptop, so this is the only way she can do her writing.

The best I can do for you is direct you to www.ifixit.com to see if you can find something there that can help. With a machine that old (circa 2005) and one that is liquid cooled, you may be fighting an uphill battle to get it repaired. If the logic board is the problem, it definitely won't be worth repairing.

You can always pull the hard drive from that machine and buy a second hand Mac to attach it to and copy the data from it. Your girl friend can continue to write her articles that way.

I found working logic boards for $50. You think I could just swap it out? Again, I've already pulled out the whole LCD and refurbished it, so I'm pretty well versed on the inner workings of this machine.

Check outside and inside very carefully before spending any money. That model is alas liquid cooled and it is well known after time (and it is now ten years) leaks occur so check for stains etc. This is what to look for:-


http://www.xlr8yourmac.com/systems/G5_coolant_leaks.html

twbb76 said:

I've already pulled out the whole LCD and refurbished it, so I'm pretty well versed on the inner workings of this machine.

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I guess that means it's an iMac G5, not a PowerMac G5?

gsahli said:

I guess that means it's an iMac G5, not a PowerMac G5?

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A great point! The info the OP is providing is pretty confusing.

- Post #1 says this computer has a quad-core 2.5ghz. Only a Powermac G5 had this.
- But then in post #3…OP mentioned…"pulled out the whole LCD and refurbished it".

As we know Powermac G5's don't have an "LCD to pull". But at the same time…no iMac G5 (with an LCD to pull)…have a quad-core G5 CPU.

Very confusing!

- Nick

p.s. OP also said that…"so I'm pretty well versed on the inner workings of this machine." Well not exactly. Since the proper model computer hasn't even been identified yet!

Nor on the outside it would appear.

Please excuse my autocorrect. In post three, it should have read LCS, meaning the Liquid Cooling System that I referred to in the first post. I can confirm that it is NOT an iMac, but a Power Mac.

twbb76 said:

Please excuse my autocorrect. In post three, it should have read LCS, meaning the Liquid Cooling System that I referred to in the first post. I can confirm that it is NOT an iMac, but a Power Mac.

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Thanks for the correction. That makes MUCH more sense!

- Nick