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Resolved G5 black screen, no chime, nothing...

Lud DiLettante

Lud DiLettante

macrumors regular
Original poster
Dec 17, 2015
149
27
Finland
Started the G5 today but nothing happened. The power went on but there was no chime. Tried again a few times, I think on some tries the fans started slowly but I didn't wait for them every time. Next I reset the PMU, that did nothing. Can't remember this happening to me before, I think I always got past the chime at least.
There hasn't been anything unusual that I've noticed in a long time so this was a surprise. Can't think of a cause. The inside had a thin but visible layer of dust, dunno how easily that could cause problems...
Any standard list of things to do, or is it all over now, baby blue..?
[doublepost=1482168943][/doublepost]PS. There were no red leds on, except the one in back that's always on...
 
Lud DiLettante said:
Started the G5 today but nothing happened. The power went on but there was no chime. Tried again a few times, I think on some tries the fans started slowly but I didn't wait for them every time. Next I reset the PMU, that did nothing. Can't remember this happening to me before, I think I always got past the chime at least.
There hasn't been anything unusual that I've noticed in a long time so this was a surprise. Can't think of a cause. The inside had a thin but visible layer of dust, dunno how easily that could cause problems...
Any standard list of things to do, or is it all over now, baby blue..?
[doublepost=1482168943][/doublepost]PS. There were no red leds on, except the one in back that's always on...
Click to expand...
Start with the video card. That's usually the culprit. Remove it and try and boot. If you get a chime, reseat the card firmly (after turning the Mac off again) and try booting again.

If it won't boot then it's probably the video card. But you can test the ram (in pairs) the same way. If none of that works it may be down to logicboard/cpu.

Note that this assumes you do not have other cards installed. If you do have other cards installed, try taking them out one by one and seeing if the Mac boots each time. Could be one of your cards failed.
 
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It could also be a power supply giving up as this is another common issue which explains why there are no red LEDs towards the front of G5, this is what mine did when the power supply gave up. This would also explain why a pmu reset didn't do anything.

May I ask what model of G5 you have??
 
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Thanks E & C. I never touched the video card before but I see from YT guides it's easy to remove. Unfortunately I have no other net access at home presently (smart phone broken too ;D) so following instructions isn't that easy. Thus, I really hope it's not the power supply as replacing it seems tricky... (well, I'd have to get a new one to begin with, of course)
You may ask, Chibiterasu, but I seem to have forgotten the exact specifics... but it's a dual. I can check once I'm home again... I'll try the video card thing today at least. But unless some sort of magic happens I probably won't be back on the forum until tomorrow.
 
Lud DiLettante said:
Thanks E & C. I never touched the video card before but I see from YT guides it's easy to remove. Unfortunately I have no other net access at home presently (smart phone broken too ;D) so following instructions isn't that easy. Thus, I really hope it's not the power supply as replacing it seems tricky... (well, I'd have to get a new one to begin with, of course)
You may ask, Chibiterasu, but I seem to have forgotten the exact specifics... but it's a dual. I can check once I'm home again... I'll try the video card thing today at least. But unless some sort of magic happens I probably won't be back on the forum until tomorrow.
Click to expand...

Well fingers crossed that we hear good news. Do try everything eyoungren said first to narrow it down. Ah that's alright I'm sure you'll update when you know. Well if it is the power supply it's a fun evening as you kinda have to remove both processors and having a guide while you doing it is always good. (Some people on YouTube say you only have to remove one processor on a dual machine, but I removed both as you get much more room to manoeuvre the power supply in and out)
 
Surfing around the web today I ran into this downloadable (June 2004 to Early 2005 single & dual processor PPC models) powermac G5 service manual PDF. I don't know what model you have but there are trouble shooting materials in it that the "certified" apple service folks would've used.

http://tim.id.au/laptops/apple/powermac/powermac_g5.pdf

Anyhow, it can help you to more quickly and confidently troubleshoot your sick powermac. Best of luck to you :)
 
Any flashing from the power LED at the front of the machine either when the power lead is connected or you try and power the G5 on?

I recently replaced the PSU in my 2.0DP, it's a known weak spot.
 
OK, for various reasons I didn't remove the video card yet but I now had a better look at instructions and will probably do it tonight.
About the model, I only took down "ck34905zqeu" thinking that covers everything ;D but I think it's the original dual 1,8 GHz if that's enough info...
Thanks for the link Rhian, these should be helpful.
MagicBoy: I haven't noticed any unusual flashing of the power LED but I remembered I have noticed a red LED inside flashing when I power off though I'd guess that's just what it's supposed to do.
 
Alright, I took out the video card but got no chime when powering so I guess that's not it...
Didn't test RAM yet as forgot something but now I did remember :D So that's what I'll do next. I bet it's the power supply anyway... (not accepting the possibility of CPU yet, of course ;D )
About the red LED - it just flashes once behind the power button when I power off.
 
If you feel that this is caused by your PSU, the complete guide for troubleshooting the PSU is below starting on page 184 for your model powermac g5.

Power-on LED does not illuminate when power button is pressed, fans do not
spin, and there is no boot tone or video

1.Verify power outlet is good.
2.Replace power cord.
3.Reset the logic board. Refer to “Resetting the PMU on the Logic Board” in this chapter.
4.Verify power supply cables are fully connected.
5.Check for trickle voltage on the power supply connector. Refer to “Power Supply
Verification” in this chapter. If verification fails, replace power supply.
6.Reseat front panel board cable.
7.Verify that processors are properly seated.
8.Verify that processors’ mounting screws are properly tightened.
9.Replace front panel board cable.
10.Test the front panel board and power button using the front panel board troubleshooting
tool. Refer to “Front Panel Board Troubleshooting” in this chapter. If the computer starts up
correctly, go to step 11. Otherwise, go to step 14.
11.Test whether the front panel board or power button is at fault. Remove the installed front
panel board and swap it for the known-good front panel board in the front panel board
troubleshooting tool. Then connect the troubleshooting tool to the logic board of a
known-good Power Mac G5 and start it up using the tool. If the computer does not start up
correctly, go to step 12. Otherwise, go to step 13.
12.Replace front panel board.
13.Replace power button.
14.Replace logic board.
15.Replace power supply.

I assume you don't have additional parts or G5s to help trouble shoot starting at around step 10. Does anyone know how to check this without the "FPB tool"?

I hope you're able to fix your mac. Good luck!
 
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Thanks Rhian but I'm beginning to accept the idea it may be a processor or the logic board anyway... I tested the RAM, no change. And the instructions seem to indicate that if the fans work then it's not about PSU, and even though I seemed unclear about whether the fans work I did verify they work normally. (Maybe I was also unclear about the Power-on LED but it does illuminate.)
Luckily I don't think I need the G5 for anything important before or during Xmas holidays (I'm not even home) so it's not as if I'm in a terrible hurry to get it fixed.
Am I right in assuming that the G5 Dual should work with only one of the processors too? (In case I remove a faulty one.) Wonder how much difference it makes. Otherwise I guess I'll have to start considering whether I'll have to get a new processor/logic board/computer.....
 
Ahh my bad - I misunderstood. Yes, per the linked service manual, you can indeed check each processor by removing it and attempting to boot off of the other. Here's the included trouble shooting process for that scenario.

Power Mac G5: Power-on LED illuminates when pressed in, but goes
out when button is released, fans spin, and there is no boot tone or video

1.Verify that the processors are properly seated.
2.Verify that the processors’ mounting screws are properly tightened.
3.Remove the processors and check for damage to the logic board under the processors. If you
see damage (see example below), replace the logic board.
g5 circuit board damage 2006 service manual.jpg

4.Remove lower processor. If the computer starts up correctly, go to step 5. Otherwise, go to
step 6.
5.Replace lower processor.
6.Replace upper processor.
7.Check for trickle voltage on the power supply connector. Refer to “Power Supply
8.Verification” in this chapter. If verification fails, replace power supply.
9.Replace logic board.

Good luck.
 
Thanks everyone, I'll be back sometime after Xmas (now on my mother's tablet ;D ). Happy Xmas, all (if that's your
thing).
 
OK, back at last. Even the library had net connection problems yesterday...

So it appears I'll have to try either removing a processor or check for trickle voltage. Or both...
Wonder why the specific order in the manual, if one buys a new processor and then it's the trickle voltage after all... (or maybe my brains aren't working post xmas.)

Anyway, I'll print a coupla more pages off the manual & start trying...
[doublepost=1482939297][/doublepost]Well damn, seems I'll need to get all kinds of tools etc for these... a cup hook..?! :D Fine...
 
Oh, I don't need the cup hook... luckily. The manual is a little confusing as to which model is which, or maybe it's my head again. But I do need another kind of screwdriver. Gonna buy that and be back here tomorrow, maybe. Or maybe next year... °_°
 
:D Well, I hope so... the screwdriver was still too short and I'm going back to the store again... -_- This does seem endless. I'll report here around 2017. ;) So, happy new year...
 
Hah - that's happened to me on more than one occasion. I hate short screw drivers. For those really deep, hard to reach screws, I found it worth spending the extra couple bucks to get a magnetic set. I can't tell you how many times I dropped a tiny screw just to have it roll around to the back side of the logic board. What a pain in the butt to get out! :D
 
Whew..! I'm on the G5 now! Had to travel to the city limits to get a suitable screwdriver, not that it's magnetic at that... but I managed... (picked up a screw with scissors, etc ;D )

So I got the lower processor out, and that was it. Everything runs better than I expected on just one processor. A little slow at times, and Onyx froze when repairing permissions but on the second try it finished fine.

So, what should I do next, could I survive on just the one processor..?
 
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Thanks Rhian. I never knew about thermal paste or daughter cards before... I was planning I'd try reseating the processor but since everything seems pretty fine with just one processor I don't know how soon I'll be motivated now (I also wonder how I'm gonna get a couple of those screws back in ;D )... but the paste thing does sound like a good idea.

Anyway, this looks like the happy end of this particular thread. Thanks again to everybody!
 
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