Mac OS 9 Lives

Mac OS 9 Discussion => Hardware => Topic started by: fuego on October 29, 2014, 11:39:11 AM

Title: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: fuego on October 29, 2014, 11:39:11 AM

I've just completed a fan mod http://macos9lives.com/smforum/index.php?PHPSESSID=ctqr72ngaoi59g44dggo0u4g75&topic=1922.0 (http://macos9lives.com/smforum/index.php?PHPSESSID=ctqr72ngaoi59g44dggo0u4g75&topic=1922.0)

I replaced a 120mm fan http://www.newegg.com/Product/Product.aspx?Item=N82E16835226013 (http://www.newegg.com/Product/Product.aspx?Item=N82E16835226013)
and the two 60mm in PSU http://www.newegg.com/Product/Product.aspx?Item=N82E16835230018 (http://www.newegg.com/Product/Product.aspx?Item=N82E16835230018)
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after the mod the computer wont turn on. when power is pressed, the button lights up and it fades seconds after computer dies. i tried this with the side open i can see the fans kick, there is also a red light that comes on next to the ram.

the strange thing is when i plug in the original factory 120mm fan everything works just fine.

Its without the factory fan the computer refuses to turn on.


I've tried the new 60mm fan, the new 120mm fan, the old 60mm fan on that port and nothing is "sensed" by the machine. only thing that works is the factory 120mm. really strange.

to isolate the problem i disconnect everything internally except the power button to logic board and Psu to logic board, same thing the power button lights up then the machine instantly dies.

plug in the factory fan = all good.


here are my specs:
Apple Power Macintosh G4 1.25 DP (MDD) Specs
Identifiers: Mirrored Drive Doors - M8573LL/A - PowerMac3,6 - M8570 - 1914
August 13, 2002 Power Macintosh G4 1.25 DP (MDD) 9.2.2 *high end model*
http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_1.25_dp_mdd.html


others have posted that they haven't experience anything like this. I'm starting a new topic since this is a complete new problem.

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: MacTron on October 29, 2014, 01:00:48 PM

This is unusual... I don't remember this happened to me when doing "similar" mods...

(http://macos9lives.com/smforum/index.php?action=dlattach;topic=927.0;attach=242;image)

In this picture we can see the original fan, but a different fan with manual regulation was placed before this one...

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: Protools5LEGuy on October 29, 2014, 01:21:50 PM

It sound to me like you need a new battery... Use a voltmeter to test it
When I put Digi 001 with the rack and the cable on the MDD it doesn't boot, while it boots on the DA...
And do the same power button thing.

When I put a AP2496 on the MDD, it makes the same thing. I pull out and it works...

Try to reset parameter RAM (PRAM) with the original fan. And pull off after to see.

If not...

I would take out one of the 2 2-drive bay and would put the original OEM fan in that place. Or even better, on the cd bay if the cable is long enough.  I guess you could live with 0/1 DVD unit. After installs I pull off my CD/DVD drives to have more IDE space...  ;D 

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: fuego on October 29, 2014, 01:56:42 PM

ill try the battery, the machine forgets date every-time thats a good indicator battery is gone. (hope it fixes the issue though) keeping my fingers crossed.

thanks guys

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: fuego on October 29, 2014, 04:20:03 PM

got back form work, went to batteries plus, replaced PRAM battery, no go :( is there an art to installing PRAM battery? like unplug, wait 2 seconds, etc?

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: Jakl on October 29, 2014, 04:39:40 PM

Have you tried the PMU reset button?

Follow these instructions for your computer; http://support.apple.com/kb/ht1939 (http://support.apple.com/kb/ht1939)

I have attached a photo of the button in the MDD

Hope this helps.

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: fuego on October 29, 2014, 06:27:28 PM

Ok guys I'm not sure how i feel right now.

i did few more things to isolate the issue, came down to RAM. i have full 2GB (512/slot maxed out on mdd) and one of the ram sticks was causing this mishap. :o

Still find it strange that the i get full 2gb with the stock fan and 1.5 w/o? makes no sense to me. oh well i think i can live with 1.5 for now.

let me know what you guys think.

Title: Re: PowerMac G4 MDD wont turn on after an attempt to quiet it down.
Post by: supernova777 on October 29, 2014, 07:35:46 PM

u know this is playing with my mind because this is exactly wat my quicksilver did
and it made me think i ruined the cpu or motherboard