Power Mac G4 MDD (FW800)

[Paralel]

I was recently able to piece together a fairly decent Power Mac G4 MDD (FW800) system:

Dual 1.25 GHz G4

1.25 GB of RAM

240 GB HD (2x120) Ultra ATA/100

ATI Radeon 9000 Pro 64MB AGP 4x

DVD-R

Airport Extreme

Leopard 10.5.8 Clean Install on HDD 1

Tiger 10.4.11 w/ Classic 9.2.2 on HDD 2

For $145 USD

This will be my first "Modern" Mac system. I'm rather excited

 

[Bunsen]

That seems very well specced out for the price. Mind sharing the build story?

 

[Paralel]

Sure. Got the case w/ logic board, PSU, DVD-R, Heatsink and all relevant internal and external cabling for $49 w/ free shipping

I found a place online that was having a one-day sale on secondhand video cards and purchased the Radeon 9000 Pro (Mac Edition) for $20 w/ free shipping

Got the Airport Extreme off of e-bay for $25 w/ free shipping (although I see today someone is offering one here for $10...)

Ordered the DP 1.25 Ghz card from a store online for $50 w/ Free Shipping.

The wife of a guy I know was forcing him to reduce his stash of PC/Mac parts so I got the HDD's and RAM for free.

That pretty much covers it. The real steal was the case w/ the various pieces inside. The guy really didn't seem to know what he had on his hands, he knew it was a G4 MDD but didn't appear to be aware that it was a FW800 model, but I recognized the FW800 port right away. Considering it weighed 30 pounds according to UPS and he had to ship it 1/2 way across the US he couldn't have made very much after the shipping.

However, I'll most likely get to play with it for a little while until my car drops dead, I break yet another bone, etc... and then I will have no choice but to put it up for sale in the trading post or, shudder, up on e-bay for what I payed for it or a little less.

 

[Paralel]

I actually ended up winning an auction on e-bay I wasn't expecting to win.

That'll change my video configuration to a Nvidia GeForce4 TI 4600 128MB and bring my total up to $169 for the system.

Now I'll have to find someone who wants a Radeon 9000 Pro (Mac Edition) for $20 & shipping...

 

[Blessed Cheesemaker]

Is that a 64 MB Radeon, or a 128 MB one? I might be interested...

BTW, the other upgrade you should consider for your "new" PowerMac would be an SATA card. Those old PATA drives aren't bad, but when I put an SATA card and drive in my Sawtooth (with a Sonnet 1.4 GHz G4), then the thing really started to fly.

My next idea for an upgrade now is a SSD in the thing...funny how you can always come up with one more thing to try in these old Macs!

 

[Paralel]

Would an SATA card limited by a PCI bus be any better than the ATA-100 on the logic board?

 

[coius]

They would both be on the same bus. ATA/133 partly maxes out because of the PCI bus. Also, SATA seems to be more CPU friendly than PATA. I have such a card and I am not sure if I want to sell it or hang onto it. I haven't used it in a while, but if I ever get another G4 tower, I would want it. It's a Sonnet Tempo/SATA PCI card (32-bit/33Mhz/66Mhz) and it absolutely rocks. It also gets around the 128GB IDE limit. It also greatly increases the bandwidth of the HDD speed on the early powermacs (xxxx series and early G3s)

So a SATA could would not only make getting drives cheaper, but easier to get larger drives. I have used a 1TB HDD on Power Macintosh 7500/8600/9500 (all those) and they work great under OS 9

 

[Paralel]

I got the main body of my MDD... and the power supply was deader than a doornail...

Of course, as we all know, this it he most expensive part of an MDD. I hacked together an old ATX power supply I had sitting around and it sprang to life, proving it was indeed the power supply. I tried replacing the fuse in the MDD power supply and it immediately blew, it was obviously beyond my ability to repair.

I got a hold of the guy and said I wanted a refund equivalent to what it would cost me for a new ATX power supply in order to get the system up and running or I was going to dispute the charge since the condition power supply was never disclosed. He said that was reasonable and gave me back the value of the ATX power supply I ordered to install into the system.

Now my only issue is that the system is practically unsalable now. I'm going to make a proper connector so the ATX power supply interfaces nicely with the logic board without any solder/electrical tape/etc... but no one is going to want to buy a system with a hacked power supply for a reasonable price.

I should have known that was too good of a price for a barebones system...

 

[Bunsen]

but no one is going to want to buy a system with a hacked power supply

Considering the amount of noise an original MDD PS makes, if you make your adapter well, you could probably market it as an upgrade. }

 

[Paralel]

I should see if there is a market for an ATX -> MDD conversion cable. I think I've come up with a way to make the ADC functional with an ATX power supply using an adapter cable that wouldn't require modding the actual power supply in any way. I'd only need about 10 orders to be able to afford the tools I would need to make the cables.

 

[Bunsen]

There is a guy marketing ready made adapter cables, but I don't like his design much.

I got my DA booting with +5VSB going into the +27V line, but obviously that means no ADC or powered Firewire devices. I've considered adding one or two of these cheap adjustable DC-DC voltage boosters inline to make up the +27V, or a Powerbook power supply (+24V) but I've moved onto a QS since then and let that project lapse.

 

[Paralel]

I came across a website for a guy that made cables but there hasn't been any activity on his site since 2009 so I figured he was more or less out of business.

I didn't think it would be too difficult to take one of those 4 pin cables that has 2 +12V wires and make it into a single +24V line. People that have checked those +25V lines say they are actually +24V so I don't think it would be an issue.

 

[Bunsen]

take one of those 4 pin cables that has 2 +12V wires and make it into a single +24V line

Unless I'm mistaken, that's a really bad idea. You would be shorting one of your 12V line directly to ground, and would blow the supply.

 

[Paralel]

Directly to ground? I would be tying the two yellow +12V wired into a single pin and connecting the two black ground wires to two ground wires on the connector.

 

[Gorgonops]

I didn't think it would be too difficult to take one of those 4 pin cables that has 2 +12V wires and make it into a single +24V line. People that have checked those +25V lines say they are actually +24V so I don't think it would be an issue.

Uhm... taking two 12V lines and tying them together for 24 volts? Pardon my possible ignorance, but I'm pretty darn sure that *does not compute*. If you crack open your power supply what you'll find (I guarantee you) is that all the lines of a like voltage come off the same fat PCB trace to the same regulator. If you tie two together at the other end essentially what you'll be doing is using a conductor that's twice as fat, that's *all*.

I think what you're thinking of is taking a +12v line and using a -12v line as "ground" thus making the potential *between them* "24v". I've heard of people doing hacks like that to power secondary voltage regulators in dire circumstances, but it's bad for the primary ones in the supply, and you can't just "tie the wires" together. You *have* to use it to drive a voltage regulator.

 

[Osgeld]

quite right tying 2 +12 volt lines will just increase amperage and using a split rail to make a 24v difference (-12 and + 12) can be done, but yes you will need to regulate it as it will float and you dont want to send negative voltage into any logic system that is not prepared for it , and I dont know how a switching supply will act over time

It is not the worst idea I have heard this week in electronics, but I would read up on it so you dont go cooking your new toy

 

[Paralel]

I don't have an ADC display and don't own any Firewire devices so I had no intention of doing it to my MDD, but you raise some very good points.

I ran into a roadblock with my cable design anyway. I realized I was one +3.3V wire short so unless I wanted to involve an SATA connector in some way it wouldn't work. I ended up just directly splicing everything together for my MDD. Finally came up with enough of the various voltages (and a bunch of extras...) I needed after sacrificing the 20+4 connector, one 4 pin 12V rail, and an SATA connector.

At least everything is wired correctly, except for the +25V pin, which I just omitted.

I do wish I had gotten a slightly better quality power supply though. It was completely wired with 20 AWG wire. I much prefer, especially for 12V rails, to have them running over 18 AWG wires. They wires also weren't tinned, just bare copper.

The final configuration didn't turn out too bad for $193 USD:

Dual 1.25 GHz G4

1.25 GB of RAM

240 GB HD (2x120) Ultra ATA/100

Nvidia Geforce4 4600 TI 128 MB (DVI/ADC)

DVD-R

Airport Extreme

2.0 EDR Internal Bluetooth Module

New 2-Port USB 2.0 PCI Card

New Hacked ATX Power Supply

Leopard 10.5.8 Clean Install on HDD 1

Tiger 10.4.11 w/ Classic 9.2.2 on HDD 2

 

[CJ_Miller]

quite right tying 2 +12 volt lines will just increase amperage and using a split rail to make a 24v difference (-12 and + 12) can be done, but yes you will need to regulate it as it will float and you dont want to send negative voltage into any logic system that is not prepared for it , and I dont know how a switching supply will act over time

Exactly. If you have a linear supply with separate regulators then I am sure this works fine. But these are switching supplies, and work very differently! I would strongly advise against trying this with a found switching PSU.

What you probably can do is tap DC right off of the transformer output and hang your own regulator there, maybe a small LM317 circuit or such. Assuming that the output has a few volts headroom.

I will probably by modifying an ATX supply for my own future MDD recasing project. IMO it should only effect the resale value if it is or looks sloppy. Do it need with some heat-shrink tubing and it should be fine. The prices are dropping so fast on G4s now that you probably wouldn't get your money back anyway. You will just need to enjoy your prize!