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Macdog172

macrumors newbie
Original poster
Oct 19, 2022
2
5
When trying to turn on my G5, the power button will light up but immediately goes out after I stop pressing it. The fans come on but no boot chime and nothing on the monitor. The fans speed up to full speed after about a minute. The air blowing out of the machine is room temperature and never heats up. I've replaced the PRAM battery, reset the PRAM, and remove ram sticks and re-seated them to no avail. Any ideas? Thanks in advance...macdog172
 

ifrit05

macrumors 6502a
Dec 23, 2013
548
385
Near Detroit, MI. USA
Could be CPU's or trickle power. Re-seat the CPU's and check for damage. Use a multimeter to check for +5v trickle power on PSU connector (Pin 1 [+5Vstb] and 2, 4, 6, 8, 10, 11, 13, 15, 17, 19, 21, or 23 [GND])
 
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sasho648

macrumors member
Feb 19, 2020
82
38
Could be that the GPU is not synced in with the monitor - you need a connected GPU to the monitor when first booting - it needs that. After it boots a single time - you can safely remove it after (if you are going to use linux with more modern one for example).

Another option is if you remove the windshield what lights you see - there is a G5 manual on the web which describes what each light does but basically there are like 7 lights.

Or what @ifrit05 has said - I for one thought I could get away with not screwing the shunt bolts for the CPUs (near the rear fan) but this way I was playing the lucky game where sometimes it would boot sometimes it won't.

Or another option may be to check the cooling - if the CPUs overheat - it still wouldn't blew heat because the heatsink or (more likely case) the liquid cooling isn't dissipating any heat. (This would be the case if for example it was booting before but then it was freezing after some time and later stopped booting at all).
 
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konfusion

macrumors newbie
Jul 23, 2022
19
11
The symptoms mentioned by topic author can be interpreted as "This PMG5 is currently dead and does not pass initial startup process". The most common fault reasons are:
  • Motherboard failure (often due to north bridge overheat or broken solder joints)
  • CPU connector issue (bent pins or rust/dirt/oxidation), CPU also can be not inserted properly
 
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Macdog172

macrumors newbie
Original poster
Oct 19, 2022
2
5
Wow! Thanks to everyone for your responses. This forum is really amazing. I just noticed that one of the tags said "2.3 GHz". My G5 is actually the 2.0 GHz model. Sorry about that. I didn't notice when I created the tags. Also "themarble" asked if it were air or water cooled. Mine is air cooled. Hope that clears everything. I will be trying all of ya'll's suggestions today. I'll report back on the results. Again thank you all for your help!...macdog172
 
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