Sawtooth lockups / logic board compatibility question

[Super Macho Man]

I just picked up a 400MHz Sawtooth that I'm using as a file server running OS X Server 10.4. It's fine except that it locks up every 12-48 hours on average. It's a hard lock - mouse pointer freezes, nothing in the syslog, and then a few minutes later it reboots because I have "Restart after a freeze" checked in System Preferences. I have noticed that it seems to only happen when I am VNC'ed into it. Could the VNC server (Vine Server) be causing it?

The specs are:
400MHz G4
(See below about the RAM)
Firmtek Seritek 1V4 PCI-X SATA card
Intel Pro 1000 PCI gigabit card
1 master and 1 slave Seagate Barracuda III ATA drive
2 Hitachi T7K500 SATA drives

I first suspected a RAM problem. I have like 10 128MB PC133 DIMMs from spare parts on hand, and I can't be 100% sure that they are all good. I first tried with 4 DIMMs, 512MB. Freeze after ~24 hours. Swapped those out with 4 others. Freeze after ~12 hours. Took out two of those, running w/ 256MB. Freeze after ~48 hours. Swapped out those two with two others - another freeze. I took out the video card and modem since I don't use them anyway, same freezes. Just now I took out the network card (Intel PCI gigabit) and am using the built-in, just to see if that could be causing it. If that doesn't solve it, I'll take out the Firmtek SATA card next. If THAT doesn't solve it, I'll swap the logic board I guess.

I'm already suspecting the logic board... my question is, my Sawtooth has a 1st revision board, with the uni-N revision 3 chip that doesn't support dual processors. Can I replace it with a 2nd revision board with the uni-N revision 7? I know that the PSU in the Sawtooths that came with a rev7 board was 228 watt, as opposed to the 200 watt unit I have, but will it still work? I don't think I need a high-wattage PSU since it's only a 400MHz G4 and although I have 4 HDs, they only use about 6 watts each and do staggered startup and I have no video card or optical drive installed.

Also, I noticed that the PRAM battery is totally dead. I've got a new one on order. Currently running with no PRAM battery. Might that be an issue?

 

[Sherman Homan]

Generally, when the logic board battery dies, it causes start up problems. But, once the machine is up, the battery doesn't do anything. You can reset the date/time and any other defaults, they will stick until you shut down again.
I don't know if you can swap logic boards, but I have seen G4's with bad ram slots. No matter what chip was in a slot the machine would inevitably lock up. Yank the chip, leave the slot empty through tedious trial and error, see if you can find it. Good luck with it!

 

[Angrist]

I'd recommend running a RAM tester like memtestosx. It sounds a lot like a RAM issue to me, but the swap method isn't very accurate and takes too long for my tastes.

Otherwise ... I'd suggest unchecking "sleep hard drives when possible" in the energy saver. I was having crashing / booting issues with my DA PM, and unchecking that box cleared it right up. (After 4 days of swapping drives, cables, cards, and everything else i could think of.)

 

[Super Macho Man]

Sleep HDs is & has been unchecked. I've tried memtest, although I only left it running for 12 hours, not sure how long it's supposed to go. It doesn't really work well when there's only 256MB installed because it can only check that which is not being used, i.e. about 35 megs max. So I guess the swap method works better for me since I've got the patience.

After the last lockup, I took out the gigabit card, and now the current uptime is over 39 hours, a little unusual. Also installed a new PRAM battery at the same time. I'll see if there's another lock, if so, I'll put the gigabit card back in and suspect that it was the PRAM battery.

 

[Angrist]

Memtest really needs to be run in single user mode ... then you'll be able to test a MUCH larger percentage.