Author Topic: Knowing which MDD Macs to avoid  (Read 5024 times)

Offline bsharvy

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Knowing which MDD Macs to avoid
« on: June 14, 2019, 07:01:37 AM »
I'm in the market for an MDD Mac. Are there any tips to avoiding PSU and noise problems. I'm looking at this Wikipedia article, which suggests you can use serial numbers as a guide, but provide no more info. I heard the 1.42 GHZ models were later and quieter.

A limited range of serial numbers of this model was noted for a noisy fan, earning them the unofficial designation "Windtunnel G4" in some communities. Noise complaints became such a problem that Apple later replaced the machine's power supply (PSU) and primary cooling fan with quieter versions, and initiated a voluntary do-it-yourself (DIY) replacement scheme for all previously sold machines. A very common issue in the MDD models was a failing PSU.

Offline FdB

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Re: Knowing which MDD Macs to avoid
« Reply #1 on: June 14, 2019, 07:34:02 AM »
At this point in time, after so many years from actual manufacture dates… difficult to find any that might not eventually have eventual PSU problems. Unless previous owner’s have had their PSU serviced or replaced. (AcBel PSUs are easiest to resurrect / service. Samsung PSUs - not so easy.)

Andy Cuffe (Austin Texas) still works on these PSUs and resurrects them, reasonably… and did offer slight discounts for MacOS9Lives members.

As for noisy fans… many of the original “Windtunnel” fans were - or have been replaced. Still, many replace even those replacements… for even quieter operation.

Many swear by the 1.25 GHz MDDs. Both dual and single processors. The 1.42 GHz models featured Firewire 800 and there is software available to run OS 9.2.2 on them here. I’ve several of these machines but still prefer the “lesser” 1.25 GHz models. Suppose that it really depends upon what your primary intended end-use actually is because the 1.25 models seem to run OS 9.2.2 easier, or with fewer “hiccups”.

Little hints:

If the machine your interested in buying will repeatedly boot without having to unplug and re-plug the power, in between boots AND doesn’t fail to retain the actual time between boots (must have good battery) its’ PSU is passable. If not, this is the first tell-tale sign of possible PSU problems.

Boot with the door open and check all (visible) fan(s) operation. AND with the door closed to listen for fan noise levels. AND let it run a bit to see if it gets any noisier.

There’s just a few hints. Provide a bit more info on your end-use, and your geographic location… and I’m sure more will chime in here to help you out.  ;)
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Offline DieHard

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Re: Knowing which MDD Macs to avoid
« Reply #2 on: June 14, 2019, 11:52:44 AM »
Quote
Many swear by the 1.25 GHz MDDs. Both dual and single processors. The 1.42 GHz models featured Firewire 800 and there is software available to run OS 9.2.2 on them here. I’ve several of these machines but still prefer the “lesser” 1.25 GHz models. Suppose that it really depends upon what your primary intended end-use actually is because the 1.25 models seem to run OS 9.2.2 easier, or with fewer “hiccups”.

As documented here, if it is an OS9 unit only, and you prefer speed and less heat, you can make a custom MDD... take a 1.25 Single and replace it with a "Xserve" CPU...
you will then have a unit that myself (and Mactron) has the famous...

FW 2003 1.33 Ghz OS MDD !

Or Overclock the Xserve CPU
http://macos9lives.com/smforum/index.php/topic,1726.msg8203.html#msg8203

Offline FdB

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Re: Knowing which MDD Macs to avoid
« Reply #3 on: June 14, 2019, 12:20:25 PM »
...you can make a custom MDD... take a 1.25 Single and replace it with a "Xserve" CPU...
you will then have a unit that myself (and Mactron) has the famous...

FW 2003 1.33 Ghz OS MDD !

Oh these young hot-rodders!
It’s always faster… fasterFASTER!

If you don’t like the way that I drive
              …stay off of the sidewalk!


I will not begin looking to acquire an Xserve CPU.
I will not begin looking to acquire an Xserve CPU.
I will not begin looking to acquire an Xserve CPU.
I will not… (ad infinitum). ;)
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Offline refinery

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Re: Knowing which MDD Macs to avoid
« Reply #4 on: June 14, 2019, 03:02:08 PM »
you can put a 1.42 into an OS9-only MDD and it works fine. Ive been using one like that for years now. if you manage to find one with an all-copper heatsink, there's basically zero heat problems with that combo.
G4/MDD 1.42 (9), G4/GB 500DP (X), Beige G3 400 (upgraded) (9), PBG4Ti 1Ghz (X), PBG3WS 300 (9)

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Offline DieHard

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Re: Knowing which MDD Macs to avoid
« Reply #5 on: June 16, 2019, 11:14:17 AM »
you can put a 1.42 into an OS9-only MDD and it works fine. Ive been using one like that for years now. if you manage to find one with an all-copper heatsink, there's basically zero heat problems with that combo.

Yes, good point, but the Mactron 1.5 (1.33 Overclock single) stills runs cooler than a dual, and OS9 in almost all instances; won't take advantage of a Dual CPU :)

Offline macStuff

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Re: Knowing which MDD Macs to avoid
« Reply #6 on: June 16, 2019, 01:42:58 PM »
1.25 vs 1.33 lol
is the performance increase really worth all that effort? in swapping cpus?

my 1.25 will most likely stay a 1.25;
stock configuration is the lesser headache, imho.

Offline bsharvy

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Re: Knowing which MDD Macs to avoid
« Reply #7 on: June 16, 2019, 07:30:17 PM »
The 1.42 GHz models featured Firewire 800 and there is software available to run OS 9.2.2 on them here. I’ve several of these machines but still prefer the “lesser” 1.25 GHz models. Suppose that it really depends upon what your primary intended end-use actually is because the 1.25 models seem to run OS 9.2.2 easier, or with fewer “hiccups”.

Hi, thanks for the reply. I was thinking of the last generation of 1.42 GHZ modelss, that could boot OS 9. I figured they would ahve taken the problems with earlier models into account.

On separate note, can anybody identify this Mac, and advise on whether it's worth $50 sans harddrive.
https://portland.craigslist.org/mlt/sys/d/portland-apple-powermac-g4-quicksilver/6908137907.html


Offline MacTron

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Re: Knowing which MDD Macs to avoid
« Reply #8 on: June 17, 2019, 06:27:49 AM »
1.25 vs 1.33 lol
is the performance increase really worth all that effort? in swapping cpus?

my 1.25 will most likely stay a 1.25;
stock configuration is the lesser headache, imho.

The 1.33 is 6% faster than the 1.25, It have 2Mb of L3 cache which increases around 5% the overall CPU performance. So we have a 11% faster CPU. OK at this point It's a personal option because an 11% increase in performance it isn't so much ...
But if we overclock it to 1.5 Ghz ( which is a walk in the park ) we have an extra 13% of speed increase, So we have an 24% faster CPU than a stock 1.25, which in my opinion is actually worthwhile.
Please don't PM about things that are not private.

Offline macStuff

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Re: Knowing which MDD Macs to avoid
« Reply #9 on: June 17, 2019, 09:37:16 AM »
bsharvy: its not an actual quicksilver; its a "digital audio" g4,
i personally would grab it if you need a g4; its got alot in common with the real quicksilver units;
and i think u could order a 933mhz quicksilver cpu and swap it in; am i right guys?
are the digital audios compatible with the quicksilver cpus? they haev the same 133mhz FSB/Mem speed i think

ive never had a digital audio g4 ive always wanted one, but i have a sawtooth + quicksilver + mdd already;
dont need anymore G4s lol but if i had the chance to score one i probably would grab it

Mactron; i already knew your opinion would be that ;)  i stated my opinion; my opinion is different from yours.
thank god we live in a world where everyone is not the same.

Offline Protools5LEGuy

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Re: Knowing which MDD Macs to avoid
« Reply #10 on: June 17, 2019, 01:41:08 PM »
Chris,  all D. A.  can use the QS CPU daughter board if you make the 4th leg mod.
That mod is just give +12 volts to that 4th leg.
I have a DA originally 466 MHz and upgraded it with QS'02 GHz dual daughter board.
Looking for MacOS 9.2.4

Offline macStuff

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Re: Knowing which MDD Macs to avoid
« Reply #11 on: June 18, 2019, 04:08:51 AM »
i dont have a DA. tell the guy asking the question, Bsharvy! not me!
im not doing any cpu mods.

Offline refinery

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Re: Knowing which MDD Macs to avoid
« Reply #12 on: June 20, 2019, 04:45:22 PM »

But if we overclock it to 1.5 Ghz ( which is a walk in the park ) we have an extra 13% of speed increase, So we have an 24% faster CPU than a stock 1.25, which in my opinion is actually worthwhile.

I would never attempt overclocking a 7455A by that much, but a 7455B would probably handle it fine; Ive had A's which could not even tolerate the 1.25/1.33 modification. Sadly there's no way to know which you have except to clean the thermal paste off the CPU and physically examine it to my knowledge.
G4/MDD 1.42 (9), G4/GB 500DP (X), Beige G3 400 (upgraded) (9), PBG4Ti 1Ghz (X), PBG3WS 300 (9)

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Offline macStuff

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Re: Knowing which MDD Macs to avoid
« Reply #13 on: June 21, 2019, 09:21:09 AM »
its a walk in the park apparently; if hes saying its a walk in the park; that probably means it is easy to do and little to no risk;
 

Offline bsharvy

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Re: Knowing which MDD Macs to avoid
« Reply #14 on: July 02, 2019, 09:45:37 AM »
I bought that Digital audio G4. It's the 466 MHZ model. Nice that it has a video card that can do digital. But, since it doesn't have a hard rive, I was wondering about the best way to boot it. Would that be with an externa Firewire drive? I'm assuming USB 1.1 would be painfully slow.

Offline ACX

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Re: Knowing which MDD Macs to avoid
« Reply #15 on: September 10, 2019, 02:46:54 PM »
I've been repairing MDD power supplies for more than 10 years, so I can safely say there really isn't any such thing as a trouble free power supply.  They didn't use the best capacitors, and now they're over 10 years old. 

There are four different power supplies used in the MDD.

AcBel 400W, AcBel 360W, Samsung 400W, and Samsung 360W.  The 400W models are the noisy ones, so most people would prefer the 360W, but if noise doesn't matter, they do run cooler.  There's no electronic difference, just slower fans to make them quieter.  The reduced air flow results in 10% less power capacity.  You can turn any 400W into a 360W by replacing the fans. 

I don't recommend any of the super quiet fans that are available because I've never seen one that provided adequate air flow.  Those boutique fans often don't even come close to the CFM they claim.  I've searched for quieter fans from reputable manufacturers, and I've never found anything that was significantly quieter without sacrificing a lot of air flow.  A properly functioning 360W shouldn't be that noisy anyway.

There are pros and cons between the AcBel and Samsung, but overall they're about the same quality.  I do slightly prefer AcBel because they have better overload protection (including protection against internal faults). 

I've seen a several Samsungs that were beyond repair due to an overload (scorched and melted circuit board traces).  I've never seen an AcBel suffer any kind of catastrophic failure.  Having said that, with good capacitors both brands are very reliable.  Whatever you do, don't replace a blown fuse in a Samsung.  It will blow instantly, and it will cause more damage (possibly serious).

If anyone has any questions, or need a power supply to be repaired, feel free to contact me directly.  You can take $10 off my ebay price, and even more for multiple power supplies at the same time.

Andy Cuffe

Offline GaryN

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Re: Knowing which MDD Macs to avoid
« Reply #16 on: September 10, 2019, 03:29:27 PM »
I don't recommend any of the super quiet fans that are available because I've never seen one that provided adequate air flow.  Those boutique fans often don't even come close to the CFM they claim.  I've searched for quieter fans from reputable manufacturers, and I've never found anything that was significantly quieter without sacrificing a lot of air flow.  A properly functioning 360W shouldn't be that noisy anyway.

First and foremost, it's great to hear from you. Thank you for providing competent service to our community!

I absolutely agree with you about the MDD fans. I've watched, literally for years, as one DIY expert after another has raved about the latest boutique fan or fans they've found that somehow move as much or more air as the originals while making only half as much noise, somehow defying the basic laws of physics in the process.

I've resisted repeatedly posting negative comments about this, because everybody's always certain they have the magic solution and they really don't want to hear somebody yelling "Danger, Will Robinson" to spoil their day. It's a frustrating position to take trying to explain that:

1) Almost ANY fan(s) you stick in there will work…for a while.
2) The algorithm for how long involves BOTH airflow AND how much load is on the supply. 4HDDs, a full load of PCI cards plus an ADC Cinema Display and 8-hour days of busy 2 x 1.25GHz CPU work will kill an under-cooled PSU in almost NO time at all while occasional brief use of a 1 x 1GHz single with one SSD and a self-powered display may last indefinitely.
3) All of the variables of the different PSUs make the predictability 10 times worse.
4) Nobody wants to hear that their just-purchased, very expensive solution may actually accelerate the demise of their PSU from "just another user", nor are they likely to run back later to post they were wrong and their PSU died a slow, painful death.

There ARE solutions to the MDD PSU noise issue but they involve stuff like "quiet boxes", extreme modifications or wireless methods of providing physical isolation of the unit. It's ironic that the noisiest PPC ever made should turn out to be a favorite among audio recordists and musicians but…

In you, we now have, finally, an real, qualified expert on these damn things. Your opinion should be seen as authoritative.

Thanks again for being here.

Offline FdB

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PSU REFURBS
« Reply #17 on: September 10, 2019, 05:59:12 PM »
Just when things were getting really quiet around here… up pops Andy. Welcome aboard!

Guess that between Mr. Cuffe and Mr. N. - these fans that I have with the changing multi-colored flashing lights aren’t really doing my MDDs all that well no matter how quiet they are? (kiddin’)

Anyway, rumors have it that Mr. Cuffe has also been known to refurbish Quicksilver and other G4 PSUs as well. So as the Fall Season is now upon us and the time for “inside duties” is right around the corner… perhaps ’tis time to send some dead PSUs Andy’s way!

And yes, thanks Andy… for showing up.
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Offline ACX

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Re: PSU REFURBS
« Reply #18 on: October 09, 2019, 08:59:22 AM »
Just when things were getting really quiet around here… up pops Andy. Welcome aboard!

Guess that between Mr. Cuffe and Mr. N. - these fans that I have with the changing multi-colored flashing lights aren’t really doing my MDDs all that well no matter how quiet they are? (kiddin’)

Anyway, rumors have it that Mr. Cuffe has also been known to refurbish Quicksilver and other G4 PSUs as well. So as the Fall Season is now upon us and the time for “inside duties” is right around the corner… perhaps ’tis time to send some dead PSUs Andy’s way!

And yes, thanks Andy… for showing up.

Yes, I do Quicksilver, and Digital Audio almost as often as MDD. 

Unlike the MDD, there IS a reliable power supply for those models.  The ones made by Delta are very reliable with no major weak points (they used good quality caps).  I've repaired hundreds of AcBels, but only 4 or 5 Deltas (and those really didn't need anything).  AcBel used under rated caps which always fail prematurely, but they are reliable with good caps. 

Offline IIO

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Re: Knowing which MDD Macs to avoid
« Reply #19 on: October 09, 2019, 09:16:33 AM »
most significant difference between QS and MDD is the OS: under OS9 they are all louder.
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Offline mrhappy

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Re: Knowing which MDD Macs to avoid
« Reply #20 on: October 28, 2019, 07:25:21 AM »
ANY fan noise that's able to drown out my tinnitus is too loud! I wound up going the 'machine room' route. ;D