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Making a G4 FW800 OS9 bootable.

I have just acquired this machine:

g4fw800.jpg

I bought it hoping it as an MDD, but unsure. Turns out it was a FW800. Oh well. All is not lost.

I intend to retrofit it to MDD spec and use it as my main OS9 boot machine.

I'm sure a motherboard swap is in order. But what else?

Help me, oh knowledgable compatriots.

 
As far as I know you need one of the non-FW 800 boards, and the special MDD OS 9 CD. I hear Apple will send you one if you explain your situation. I also hear they'll send you 10.5 so you can run a modern version of iTunes and buy digital content from them (or something like that). Someone else will have to confirm that.

Since you said you were looking to stock up on parts, you could buy a complete MDD capable of OS 9 and sell the motherboard to help fund other purchases. Everything else should be good for spare parts. Or sell the motherboard and use the funds to buy one that'll take OS 9?

 
MoBos appear to be available and cheap enough on eBay. Certainly cheaper than a whole nother machine.

So a MoBo swap, and the specific MDD OS9 CD. The CD will be harder.

Hmm. Any other parts or pieces?

 
As far as I know, no. I've never owned a MDD or done said swap, so I'd feel better once someone else confirms this. Keep in mind the faster boards after these went back to supporting 9...although any of them will be fast enough.

 
What faster boards after what went back to supporting OS9?

You'll have to elaborate. I only pretend to know what I'm talking about. :)

 
All FW400 MDDs support OS 9.2.2. This includes the "MDD 2003" made after the FW800 models.

None of the FW800 MDDs can do 9.2.2. As you may know, these are the ones with the single FW800 port on the back, and an Airport Extreme slot on the logic board instead of an Airport slot.

 
Ah, I see now. I wasn't aware of the MDD 2003.

It looks like that's probably got the board I need.

http://lowendmac.com/ppc/mdd-power-mac-g4-1.25-ghz.html

Unlike the original MDD models which all had dual G4s, it has only the single 1.25 ghz chip. My FW800 has a single 1 ghz chip. I would suspect they would be the best match? Or should I find a board that has the same 133 bus instead of a 167 bus?

Thoughts?

 
If you're going to pick up another motherboard then I'd go for the one with the faster bus speed. But if you're going to use that 1 ghz processor with it, you may have to change the resistor settings on it. Right now it's set to run at 7.5 times bus speed. With the faster bus speed it'll try to run at 1.25 ghz which it may or may not do depending on your luck.

 
If you're planning to keep the machine for a long time then you need to have a spare PSU since the MDD PSU's have a poor reputation. Unfortunately, they are not cheap. I haven't looked at eBay for a while but about a year ago the cheapest you could find one was about $70.

 
Those MDD 2003s were what I was talking about, sorry not to specify! Like waynestewart said, faster makes more sense unless you buy a board without a processor and need to use the existing 1 GHz on the new OS 9 capable board. I'm sure OS 9 will be fast either way, so price will probably be more important than speed.

 
I've called around quite a bit and talked to a bunch of different people, all skeptical:

"Why are you doing this? MDDs are built for OSX, not OS9. And their PSUs are crap!"

"This is very complicated. You're probably going to ruin your logic board."

"I've never heard of this before."

But this can't be a hard process. It just shows how inside the box many people are. I guess it's because they do what they do to actually, you know, get paid by people. I'm just geeking around for fun.

The MDD/FW800 take apart guide I got from lists part numbers for every component in all three generations of the MDD/FW800 machines. Basically everything's interchangeable except the logic boards and the CPU cards. I could probably get a 133Mhz board and make my current CPU work, but since I'm going to all this trouble, I'm going to do it right and find a 167Mhz board from June 2003 and matching CPU. I'll need to upgrade my RAM with the new board.

Boards and CPUs are way cheaper than the machines themselves right now, and shipping is way less, so this definitely seems the way to go. Given the $40 I've got in it, I'm hoping to have the whole thing tied down for no more than $100. Not free, but given that it will be the exact machine (actually two machines) I wanted and that it includes a matching monitor, and I found it within a day of deciding, I can't complain.

Any thoughts on whether I should go with a single or dual 1.25Ghz chip? The logic board is the same. I know that OS9 won't get much benefit from the dual chip, but OSX will, won't it? What about heat? Will I have more heat to deal with with two chips?

 
Last edited by a moderator:
BAM!

Just scored the motherboard, single chip 1.25 Ghz CPU with heatsink, 2Gigs of RAM, and modem card for $60 shipped.

Grand total, $100, and if I sell my motherboard and chip I'll make some of that back.

Definitely been my 24 hours.

 
Just a clarifying point:

At the most basic level, the January 2003 (FW800) MDD Board/ROM/Firmware is what is incompatible with 9. If you are actually looking to overcome these, A. Good for You! and B. Due to the similarities with the previous model, I'm guessing it is well within the realm of possible.

If you merely want Jan '03 MDD speed in an already compatible '02 MDD or June '03 MDD then just get get one of the Dual 1.42GHz CPUs used in the Jan '03 and pop it in. You'd have the best of both worlds.

As far as I know, the CPUs are compatible across the entire MDD line.

In regards to the original '02 MDD that shipped with an 867 G4 and 133 Bus. If you put a faster CPU in it, will it automatically jump to the 167 bus, or is that an exclusive feature of the '02 MDD boards that shipped with a 1GHz or better? (AKA, is there any REAL difference between the slower models that run at 867/133 and the faster ones that run at 1GHz/167 other than the different CPU card?)(AKA, if you take a June '03 MDD that shipped with a 1.25/167 and pop an 867 in it, will it step down to 133?)

Edit - Relevant: viewtopic.php?f=13&t=17867

 
Here’s how it works with the MDD. The motherboard bus speed is controlled by a resistor setting on the motherboard. With a 133mhz motherboards it's possible some components may be pushed a little when you up the bus speed. I’ve only personally upped the bus speed on a couple of MDD motherboards. With them there was no difficulty with the speedup. Someone i know has been using a speeded up motherboard for around 8 years if I remember correctly.

As to CPU speed, a resistor setting on the processor card governs it’s speed. That resistor setting has the cpu running at so many times the bus speed. For example 1.25 ghz cpu on a 167mhz bus would be set to 7.5 times the bus speed. If you were to move that processor card over to a MDD with a 133mhz bus then that cpu would then be running at 1ghz. However if you changed the resistor setting to 9.5 times then it would run at a little over 1.25ghz on the 133mhz bus. Changing those resistor setting is also how you do overclocking on the MDD.

Another factor in moving to a faster motherboard is RAM. Sometimes MDDs with slow bus speeds contained slower RAM. But RAM is pretty cheap nowadays if you need it.

 
As it is, I bought the complete motherboard/CPU/heatsink/RAM package from a guy who had the MDD June 2003 1x 1.25 Ghz machine. Basically he's parted his machine and I'm getting its core, so there shouldn't be any conflicts at all. Just a cleaning check and maybe some new thermal paste. Otherwise GTG.

And if for some reason I want to return my machine to stock, I simply put the original mobo/CPU/RAM etc. back into it.

 
Thank you waynestewart for the excellent clarification. Perhaps you are willing to add the relevant bits to the sitckied G4 cpu swap thread?

 
That's some good info waynestewart.

"This is very complicated. You're probably going to ruin your logic board."
That one made me laugh the most. You were just talking about a motherboard swap, right? If so that's only maybe true if you take breaks to shuffle around the carpet in your socks a few times while doing it. :scrambled: :o)

The built for OS 9 thing has a few holes...if the other board supports 9, it was built for it. I hate to think what their reply to installing Linux may have been! Never having heard of it is just too easy to make fun of so I'll just pass on it.

I think the replacement board should be just the ticket. You said you planned on stocking spare parts, so a few power supplies should keep you running for a long time I'd think. I know people who have been running them for a long time with no issue. I wouldn't be surprised if someone here has a genius solution to fixing or replacing them with another PSU!

 
Yes, wanynestewart, I do appreciate the information. I hope I didn't come across as brusque.

The guy I'm getting the board from on eBay is turning out to be quite the nice guy. He's done the exact conversion that I'm doing, and he's sending along the I/O panel (with no FW800 port) and some extra PCI slot covers (I'm missing some) for no extra charge.

Sweet!

 
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