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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
Hi guys.

I received a 2005 Mac mini g4 running Tiger not long ago, and it does the weirdest thing...

It seems to choose when it wants to display a video signal. Sometimes it boots without an image signal, and sometimes it displays fine.

When it decides to work, pretty much always after about 10-15 mins, it flickers a bit, and the signal goes off.
The Mac is still running because if I mash several keys on the keyboard it makes that normal error tone as if you've fallen on your keyboard.

To get it to work again, a hard reboot does nothing. I actually have to wait about an hour for it to cool, unplug everything to reset, and try again! o_O

I have tried several TV's, so its not the TV.

Its the weirdest thing. I'm using a DVI-HDMI cable, its brand new, although I know there is a chance it is faulty, but even if it is, its still the oddest behaviour!

Could it be an issue with the board? anyone have experience with using DVI, and knows about things like this?

Thanks.

It's got me ?
 

timidpimpin

macrumors 65816
Nov 10, 2018
1,116
1,302
Cascadia
My guess is that the Radeon 9200 GPU is on it's way out. A new GPU can be soldered on, but that will cost more than buying another G4 mini.

You could always just use it as a headless system. Meaning no KB,mouse or monitor, and you access it remotely from another system.
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
My guess is that the Radeon 9200 GPU is on it's way out. A new GPU can be soldered on, but that will cost more than buying another G4 mini.

You could always just use it as a headless system. Meaning no KB,mouse or monitor, and you access it remotely from another system.

You may be right. I've managed to reboot the Mac, and so far its been running idle for about an hour now. I'm going to run a graphics test to see how it copes.
[automerge]1580402703[/automerge]
Not long after I ran some graphics, it failed again.
 
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Amethyst1

macrumors 68040
Oct 28, 2015
3,427
4,368
It could also be a heat-related issue since things are fine when idling but go bonkers when under load. I'd open up the Mac, remove any dust you come across (especially on the cooling fan), give it a good cleaning and reapply thermal paste on both the GPU and CPU.

Can you get some temperature readouts using e.g. Temperature Monitor [https://www.bresink.eu/Downloads/TemperatureMonitor.dmg] and see if anything looks suspiciously high? Also, does the fan ramp up when this happens?
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
It could also be a heat-related issue since things are fine when idling but go bonkers when under load. I'd open up the Mac, remove any dust you come across (especially on the cooling fan), give it a good cleaning and reapply thermal paste on both the GPU and CPU.

Can you get some temperature readouts using e.g. Temperature Monitor [https://www.bresink.eu/Downloads/TemperatureMonitor.dmg] and see if anything looks suspiciously high? Also, does the fan ramp up when this happens?

Opened up the mini, board quite clean but a lot of dust in fan and vent. 99% of that has been cleaned. Just booted up.
Need to reopen soon to replace paste and increase ram/change battery.
Mac thinks it’s 1994 but if it is worth salvaging, it’s a nice mac.

Still having issues. I'll try the above and report back.
 
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timidpimpin

macrumors 65816
Nov 10, 2018
1,116
1,302
Cascadia
Try this... open it up again and remove the battery. You need to remove the drive cage to get it out. Once you do that boot again with the battery out, and reset the PRAM at least 3 times. So boot while holding down cmd + option + P + R and let it bong 3 times. Then turn it off again and reinstall the battery.

See if that fixes it.

Here is a guide on how to get the battery out: https://www.ifixit.com/Guide/Mac+mini+(PowerPC)+PRAM+Battery+Replacement/275
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
Try this... open it up again and remove the battery. You need to remove the drive cage to get it out. Once you do that boot again with the battery out, and reset the PRAM at least 3 times. So boot while holding down cmd + option + P + R and let it bong 3 times. Then turn it off again and reinstall the battery.

See if that fixes it.

Here is a guide on how to get the battery out: https://www.ifixit.com/Guide/Mac+mini+(PowerPC)+PRAM+Battery+Replacement/275

I managed to strip down to the logic board, although at the minute I don't have a coin battery to swap. I did find this in the meantime so I will try this next time I can get it to boot.


I will try to reset the PRAM as well. Hopefully I can get it sorted.
 
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timidpimpin

macrumors 65816
Nov 10, 2018
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Cascadia
I doubt the battery needs to be replaced at all. The batteries in both my G4 mini are still perfectly good.
 
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reukiodo

macrumors 6502
Nov 22, 2013
335
160
Earth
If it becomes worse (or you are ok with potentially killing it), you can disassemble it and cut a square from an aluminum foil sheet the size of the GPU chip and with a heat gun (or a hair dryer in a pinch), attempt to reflow the connections under the chip. I've done this on a few MacBookPros and Xbox 360s to some success. There are videos which suggest baking the entire board in an oven (more precise heat) but then you're exposing more of the board than necessary.

Definitely attempt a thorough clean and repaste prior to reflow.
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
If it becomes worse (or you are ok with potentially killing it), you can disassemble it and cut a square from an aluminum foil sheet the size of the GPU chip and with a heat gun (or a hair dryer in a pinch), attempt to reflow the connections under the chip. I've done this on a few MacBookPros and Xbox 360s to some success. There are videos which suggest baking the entire board in an oven (more precise heat) but then you're exposing more of the board than necessary.

Definitely attempt a thorough clean and repaste prior to reflow.

Hi, sorry about the late reply. Crazy times.

If it works for an xbox 360, could work on this too.
 
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Project Alice

macrumors 68000
Jul 13, 2008
1,571
1,476
Post Falls, ID
My guess is that the Radeon 9200 GPU is on it's way out. A new GPU can be soldered on, but that will cost more than buying another G4 mini.
That depends on which 2005 mini this is.. If it's the secret 1.5Ghz model, I'd gladly pay dosdude to solder another GPU on it. Finding the 1.5Ghz one was hard and expensive enough...
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
That depends on which 2005 mini this is.. If it's the secret 1.5Ghz model, I'd gladly pay dosdude to solder another GPU on it. Finding the 1.5Ghz one was hard and expensive enough...

I believe I have the 1.42ghz mini, with an 80gb HDD and 256mb Ram.
Least its not entry level, not that I can do much with it, however.
 
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dacasl

macrumors newbie
Mar 17, 2019
4
4
I've been experiencing similar graphical issues with a G4 Mac Mini (1.25 GHz) that I purchased on eBay recently.

After unboxing, I connected it to my main 1920x1080 monitor using a DVI to HDMI adapter. I immediately saw lots of weird horizontal lines appearing randomly on the screen. I tried connecting with just a DVI cable, but that was even worse (lots of flickering on and off).

So next I grabbed an older 1024x768 monitor and connected it using the Mini's DVI to VGA adapter and it worked perfectly. I ran it for several hours with no glitches whatsoever.

I'm guessing the Mini has a hard time driving higher resolution displays even though the specs say it should work.
 
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xc8

macrumors newbie
Apr 16, 2020
5
0
B'ham, UK
as @dacasl wrote, I am pretty sure too your G4 is ok and work fine with a VGA monitor.
@Fusionskies just get 1GB RAM , you can even (dual) boot MacOS 9.2.2 - check the macos9lives site.
I have the same machine and I am happy running old PPC s/ware under MacOS 9
 
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Project Alice

macrumors 68000
Jul 13, 2008
1,571
1,476
Post Falls, ID
Funny enough, I have a similar GPU issue with my 1.5Ghz Mini. I posted a thread about it a year or so ago and nobody replied.
Mine only works with digital. VGA doesn't work for some reason. I've tried different monitors, adapters, and cables and it just only outputs a digital signal, never detects an analog VGA signal for some reason.
 
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xc8

macrumors newbie
Apr 16, 2020
5
0
B'ham, UK
I m not sure 100% , but is there a difference between the radeon 9200 on the 1st models vs on the one you have? What I remember is that only some "later" ATI 9200 (AGP based) (m9+ gpu) - at least on desktops/PC - had a more compatible HDMI out signal (they came too with a HDMI port)
 
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Fusionskies

macrumors regular
Original poster
Apr 30, 2015
140
119
United Kingdom
I've been experiencing similar graphical issues with a G4 Mac Mini (1.25 GHz) that I purchased on eBay recently.

After unboxing, I connected it to my main 1920x1080 monitor using a DVI to HDMI adapter. I immediately saw lots of weird horizontal lines appearing randomly on the screen. I tried connecting with just a DVI cable, but that was even worse (lots of flickering on and off).

So next I grabbed an older 1024x768 monitor and connected it using the Mini's DVI to VGA adapter and it worked perfectly. I ran it for several hours with no glitches whatsoever.

I'm guessing the Mini has a hard time driving higher resolution displays even though the specs say it should work.

Since I started using, (ironically), a larger LG monitor (still at 1920x1080), it appears to be working fine now. I think it may just be a combo of certain monitors and software.

The first display I used was Samsung branded.
 
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