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Power Mac G4 MDD

Hi Everyone!

I need some help and I know this is the place to go.

I just picked up a Power Mac G4 1GHz Duel's (MDD) 2002 model, runs like a champ for $0.00. A friend gave me a 1.25GHz Duel 2002 model that won't power up. Here is my question, because I don't know whats wrong with the 1.25GHz can I swap the processor from the 1.25GHz and use it on the 1GHz model to verify if the processor is good, or if the processor is bad on the 1.25GHz could that damage the motherboard on the working 1GHz machine?

Here are the motherboard model numbers if that helps

1GHz Duel = 820-1453-A (2002)

1.25GHz = 820-1474-A (2002)

My ultimate goal is to find out what is wrong with the 1.25GHz machine, (ie) Power Supply, Motherboard or Processor

Thanks In Advance!

MajorMacintosh

Power Mac G4 MDD-OTHER, Mac OS X (10.5.8)

Posted on Apr 1, 2013 7:37 PM

29 replies

BDAqua

Level 10

239,369 points

Apr 5, 2013 11:51 AM in response to MajorMacintosh

A possiblly cheaper BT option, for 10.3.9 & up...

http://eshop.macsales.com/item/IOGear/GBU421/

Apr 7, 2013 7:53 AM in response to MajorMacintosh

Hi All,

Update:

I have a USB Bluetooth adapter from IOGEAR #GBU421 but not working on this system.

I have a question on the processor upgrade, everything seams to be working, however now

the L3 Cache is 1 MB (per CPU) shouldn't it be 2 MB (per CPU)?

The 1.25 DP processors came from a FW 800 machine, what would be different in those processors?

I understand the differences in the motherboards between these two machines, but the processors.

Any Ideas Anyone!

Thanks

BDAqua

Level 10

239,369 points

Apr 7, 2013 11:44 AM in response to MajorMacintosh

Apple

The first appearance of DDR technology in Apple computers was not in main memory,

but in the form of the backside or ‘L3’ cache interfaced to the Motorola PowerPC G4

7450 CPU. The early Apple processor design utilized 1MB of DDR cache (the

PowerMac G4 733 using the Digital Audio motherboard.) Other designs use 2MB of

DDR cache for L3, although some of the recently introduced Apple offerings have moved

back down to 1MB of L3 DDR.

www.powerlogix.com/downloads/SDRDDR.pdf

Apr 7, 2013 12:20 PM in response to MajorMacintosh

According to this, the only FW800 processor with 2MB of L2 cache per CPU was the dual 1.42GHz.

BDAqua

Level 10

239,369 points

Apr 7, 2013 3:29 PM in response to Dave Hamilton

Great work/find Dave, thanks! 🙂

Apr 7, 2013 4:39 PM in response to Dave Hamilton

oops.. I meant "L3".

Apr 7, 2013 9:12 PM in response to MajorMacintosh

Hi All,

Mystery Solved.

I did have a 1.25GHz DP (MDD) new in 2003, and it did have 2MB of L3 Cache (per cpu). I used to boot into OS 9.2.2 so it was not a FW800 machine. What I did forgot was the 1GHz DP (MDD) had only 1MB of L3 Cache. That explains why I have only 1MB Cache is because this was originally a 1GHz machine before I upgraded the processor, and yes the doner machine I got the processers is a FW800 DP 1.25GHz again at 1MB Cache.

Thanks for everyone's input.

The Following is taken from Apples Spec Sheets

Power Mac (MDD)

M8573LL/A Dual 1.25GHz PowerPC G4 2MB DDR SRAM per processor

M8689LL/A Dual 1GHz PowerPC G4 1MB DDR SRAM per processor

Power Mac (FW800)

M8841LL/A Dual 1.42GHz PowerPC G4 2MB DDR SRAM per processor

M8840LL/A Dual 1.25GHz PowerPC G4 1MB DDR SRAM per processor

BDAqua

Level 10

239,369 points

Apr 8, 2013 11:00 AM in response to MajorMacintosh

Whew, great to hear, good work! 🙂

romko23

Level 2

408 points

Apr 11, 2013 12:23 AM in response to Dave Hamilton

You can also use the dual 1.42 in a non-FW800 MDD.. I have done this myself when I used to own one and it ran just as fast.. My original processor was the Dual 1.25 w/2MB L3 Cache, so there were 2MB L3 cache dualie 1.25's.

Apr 11, 2013 7:17 AM in response to MajorMacintosh

Hi romko23,

That's great information. I have a question, would that 1.42GHz boot into OS 9?.

Another question I would like to post to everyone is:

The FW800's could not boot into OS 9 directly, so is it the motherboard, or is it the processors that limit

the booting into OS 9?

Thanks Everyone!

BDAqua

Level 10

239,369 points

Apr 11, 2013 11:21 AM in response to MajorMacintosh

It's the Logic board, faster CPUs can boot OS9.

romko23

Level 2

408 points

Apr 15, 2013 11:01 PM in response to MajorMacintosh

Sorry didn't get back fast enough.. Yes, even if its a 1.42 and the logic board is non-fw800.. it will still boot into OS 9 without any problem.. The FW800 is the hardware and the chip which prevents it from booting into OS 9 as OS 9 does not support FW800.

Apr 17, 2013 4:15 PM in response to BDAqua

BDAqua wrote:

Sadly, japamac has been chased off by insults…

That is truly despicable. An incalculably GREAT LOSS for this forum. 😮

Apr 19, 2013 9:48 AM in response to MajorMacintosh

Hello Everyone,

Wanted to give you all a update since my last posting.

Looking for a 1.42GHz (DP) daughter card and heat sink from a FW800 (anyone have one?)

Started having some issues with the power supply AcBel #APl1PC36 Rev.B. Causing intermittent lock-ups waking from sleep and such. I have this connected via ADC to my Apple Cinema HD Display 23". As I

understand this display uses apx. 70 watts that is drawn from the PSU. It looks like I will need to rebuild the PSU as some capacitors with age are failing. Before I go on, yes I do know you can mod and install a standard pc PSU but you loose two very important functions. #1 You can't use a ADC display, #2 Sleep can be a issue, as pc PSU's don't provide the 5V needed for deep sleep. With that said, I will replace a large portion of the capacitors. I will keep you all posted on this project. My resource for this project is "http://www.badcaps.net".

Also has anyone replaced the fans on the PSU and the CPU with something else, as these Mac's are 11+ years old, I wonder if "Today's Fan Technology" will help in the airflow and noise department? If you have, please post what you used and if you needed to do anything with the wires, allot of today's fans are 3 and 4 wire, and the Mac's are just 2 wire.

Thanks So Much In Advance!!, Your All Great!

MajorMacintosh

Power Mac G4 MDD