G3 beige DT and Tower power supplies different?

[Biorn]

Is there a difference between the beige Tower and DT G3 power supply pin outs?

I recently got for free non-functioning a beige G3 tower with a 333MHz processor, plenty of RAM, and a SCSI-3 hard disk connected via an ATTO SCSI card. I got it to start up fine on an old external SCSI HD with OS9 I had, but it refused to start up on the CD drive (I even replaced the CD drive with another). The G3 tower also refused to start up on an IDE drive with OSX 10.3, connected via an Adaptec PCI adapter. In all instances, the hard disks start spinning but the screen remains black.

I sighed, but realised that this motherboard was (seemed?) identical to the G3 desk top model. Since the RAM in the Tower machine are too tall to fit the DT, I decided to move a DT motherboard I had to the Tower case. Easy. But absolutely nothing happens when I try to turn on the assembled computer - not even a click!

What is going on? Are the power supplies different (they do have somewhat different sizes)?

Any other suggestions?

 

[alk]

The are different. One is ATX, the other is "custom," but I forget which is which. You might try switching the jumper marked "PS/2" and "Mac" to the opposite position.

Peace,

Drew

 

[Unknown_K]

The tower has the ATX PS, the desktop has the custom one.

 

[Biorn]

Thnaks for the information.

Drew, where is the jumper? On the power supply or the motherboard? I have not been able to find it!

Where can I find the pin out for these power supplies? I have spent hours with Google, but failed sofar.

 

[Unknown_K]

Should be in the corner with the PCI slots.

 

[MacJunky]

Look for ATX conversion guides on xlr8yourmac.com, they should have the pinouts.

In regards to the PSU, the minitower and desktop used the same (ATX compatible) while the AIO used a different one.

To find jumper J28 look at the board from the side of the rear ports. See the PERCH/Personality slot(with the PCI slots to the right of it)? Well, look at the rightmost PCI slot(closest to the edge of the board) and look at the side of the PCI slot that is closest to you. There should be a hole and the CUDA reset switch near it. It is a relatively small jumper IIRC but it is marked (on my board anyway) so should not be hard to find.

 

[alk]

XLR8 Your Mac!

That article might be interesting to you. Pinouts for the beige G3 Mac power supply are basically ATX (indeed, if you put the jumper in the PS/2 position, it IS ATX).

XLR8 Your Mac has more info about G3 systems: Articles about G3s

Peace,

Drew

 

[MacJunky]

Ok, I was wrong, I only looked at the AIO manual and it said the PSU was not the same as in the MT and DT models so I assumed that meant the MT and DT should be set to PS/2. However Apple must have been talking about the physical form factor or something.

/me slaps Apple.

http://img504.imageshack.us/img504/1783/beigepsucrapni7.jpg

 

[Biorn]

Many thanks to all of you that answered my question. Yes, the G3 Beige motherboard worked after moving the jumper. I am still struggling with the computer - the old G3s have a lot of idiosyncracies... I want it to run Tiger... It was a struggle to get it to start up on a 125 GB IDE HD connected via an Adaptec ATA-66 board - in OS 9.2. It still takes 2-3 minutes before it starts to load the system. I've tried it all: zapping PRAM, pressing CUDA, reinstalling etc ad nauseum. Wish me luck - it does run at 366MHz from a B&W, and with luck it will accept the ATI graphics card as well.

Biorn

 

[alk]

How much RAM do you have installed? Is the startup time faster when you use a drive connected to the built-in IDE controller?

-

Drew

 

[MacMan]

It was a struggle to get it to start up on a 125 GB IDE HD connected via an Adaptec ATA-66 board - in OS 9.2. It still takes 2-3 minutes before it starts to load the system. I've tried it all: zapping PRAM, pressing CUDA, reinstalling etc ad nauseum. Biorn

I had this problem with a 160GB drive on my G4 - it caused slow startups, wakeups and a few other problems. It turned out I had accidentally left the drive in "Slave" mode when it was the only drive in the machine. Moving the jumper back to "Master" solved everything. This is obvious I know but it's an easy mistake to make, so it is worth checking to make sure your drive is not in "Slave".

 

[Biorn]

Thanks again for the responses.

RAM: 640MB (2x 256, 1x 128), pulled from a B&W rev1 that suddenly died when its hard disk crasched due to mechanical failure; I assume the motherboard is gone as not even pressing the CUDA switch helps...

Did I leave the new hard disk set on SLAVE?. No. It is the only HD I have connected to the computer now, partitioned into an 8GB for the OS and the remainder for files etc. It is connected to an Adapted ATA66 PCI board. I have not tried the built in ATA connection since the disk is a modern 125 MB disk that is unlikely to function in these old G3s. What however has worked consistently, but still with the long delay, is booting from an old 500 MB SCSI drive; dog slow but reliable...

I got the G3 to start up on the 8GB partition with OS 9.22 installed (through my G4). I then added XPostfacto v 4, inserted the Panther Install CD, launched XPostfacto, and crossed my fingers during the restart.

Sigh. The computer started up, after a longish wait, with a black screen containing some kind of error messages I fail to understand. I guess these are some OF messages, or kernel panic... Seems I will have another long evening trying to go through all the advice the XPostfacto has for troubleshooting.

Biorn

 

[The Macster]

The screen that you see will be it booting from the OS X CD in Verbose mode - when the text stops scrolling, does it say "panic - we are hanging here" at the end? If not, then you just need to give it time to boot into the OS X installer. The modern hard drive will work in the Beige G3 - you should try installing X with the drive connected to the internal bus and the first 8 GB of the drive as the target for OS X installation. XPostFacto often doesn't work when you have PCI cards like that installed, you should try removing everything except your video card (you need a separate video card for it to work with 10.3 or 10.4).

 

[Biorn]

Thanks again!

No, I did not see "panic -we are hanging in here". I remember it said something about BOOT, and BYE - both were OK'd, and then finally there was a prompt of some kind. Nothing more happened and I pulled the plug after 5 minutes...

I will try installing with the drive connected to the internal bus. Undoubtedly, I will be back with more comments...!

Biorn

 

[The Macster]

Hmm, that sounds as though it might be Open Firmware instead - is it definitely white text on a black background, I had assumed it was OS X's Verbose Mode as that is what that looks like; I think OF on mine had dark text on a light background. If it's an OF prompt, have you tried pressing the red CUDA button since you started getting the OF prompts?

 

[Biorn]

Last night I followed Drew's suggestions: removed all PCI cards except for the ATI graphics, and connected the partitioned hard disk to the internal bus. Clicked on XPostfacto, and asked the computer to start installing Panther.

It rebooted nicely, and installed the OS until completion. Great!

I restarted the G3 hoping that it would load the newly installed operative system, and crossed my fingers.

To no avail. The screen comes up with a "happy Mac Plus", and hangs for at least 30 minutes.

Sigh, I pulled the plug and went to bed...

More things to try: change to another motherboard, with freshly zapped PRAM and newly pressed CUDA, an original Beige G3 IDE 4GB, and OS 9 on an external SCSI.

Unless there are other and better suggestions?

 

[The Macster]

Did you try zapping the Pram (make sure you hold the combo down right from when you press the power button until you hear a second chime) after installing OS X? That thing with the Happy Mac happened on mind and that solved it - if X is working properly you shouldn't see the Happy Mac, it will go straight to the grey Apple logo.

 

[alk]

Does that happen to be a Western Digital hard drive? WD drives fail to boot on some systems when hooked up to IDE cards (particularly RAID cards, but not necessarily restricted to IDE RAID controllers - I have a WD 250 GB drive that just won't boot my DA G4, but it works fine otherwise).

Peace,

Drew

 

[Biorn]

Thanks again for advice.

Yes, it is a WD drive... I'll try the old 4GB next...

No, I did not zap PRAM again - I had one that prior to installing a fresh OS9.2 and Panther...

I'll post an update on pragress as soon as time allows - probably during the weekend.

I have tinkered with several old Macs in the past (Plus, SE, cx, ci, fx, Q630/700/800/900, and a slew of 7300s or above. None has been as finicky as these old G3 motherboards - not even my DA G4.