G4 DA repair

[Forrest]

I got 3 kernel panics in the past two days on my upgraded 533 MHz G4 DA Mac- not a good sign. The computer turned 10 years old last month. I backed-up the important files and opened up the computer today. After removing the dust, I found 1 exploded cap on the GigaDesigns 1.33 GHz G4 upgrade card, and the fan built into the original power supply isn't turning. There's a faint smoky smell inside the computer. I was planning on reinstalling the original 533 MHz G4 card for now, but need some guidance on the power supply fan. Is the PS fan supposed to turn all the time in this machine, or is it temp controlled? Where's a good source for power supplies?

 

[Trash80toHP_Mini]

I've got no memory of my 466DA's fan ever being off while it was running, nor do I recall any speed changes that would indicate temp control. It's still my main Mac and still running OS 9 unless I boot from the earliest (might have been bug fixed, dunno) version of X I installed out of curiosity.

ISTR that temperature controls weren't introduced until the Wind Tunnel Series sorta required some Db reduction during Proc Downtimes and Gale Force CFM levels while the Proc(s) were under heavy load.

Does anyone know which Mac was the first to offer Temperature Controls & MultiSpeed PSU Fans? :?:

I'm still lovin' my decade old G4 466 DA and I've yet to switch over to the noisier/hotter Dual GigaHertz QS02 I snagged over two years ago! :approve:

 

[MacJunky]

I seem to recall Apple using in some systems of that time fans that had a built in thermistor but idk exactly what machines those were.

Either way, just look up the specs and go get a modern fan that is as good or better and you will be fine.

 

[Forrest]

OK, thanks for the info. I'm pretty sure the PS fan was on all the time - and you confirmed it.

Time to open up the PS and see if there are any bulging caps.

 

[MacJunky]

Fans do die you know. Generally if a fan stops spinning the fan itself was the issue, not capacitors.

 

[Forrest]

Yes, but if the PS runs hot, this could cause the PS caps to fail quicker.

 

[Trash80toHP_Mini]

If the PSU Fan fails, and goes unnoticed, it can cause a whole chain of failures. Your Accelerator Card and, PSU Caps being some of the most stressed components in the system as it overheat or so I would surmise. One of out resident EEs or Mac Repair Boffins will probably elaborate/correct my WAG.

 

[Forrest]

The PS caps look OK and it doesn't smell toasty - so it looks like I just need a fan. It's a 80mm x 80mm x 25mm, 12V two wire fan. I'm having trouble finding two wire fans - all the new ones seem to be 3 wire. Can I run one of these fans with just two wires hooked up (+12V and ground)?

 

[phreakout]

Yes, the 3rd wire (probably yellow) is for the fan speed, temperature sensor or sleep mode shut off. The other 2 are obviously the power feed.

73s de Phreakout. :rambo:

 

[Forrest]

I need more help - I'm unable to determine the value/voltage rating on the Giga Designs GT-1300 1.25 GHz G4 Upgrade card that blew up, The only marking on the electrolytic cap is T0219 105C. Googling T0219 capacitor doesn't show anything useful. Anyone ever repair one of these?

 

[Concorde1993]

Have you checked the fuse in the power supply yet? It may need to be replaced.

 

[Forrest]

The computer is working fine after installing a new PS fan and the original 533 MHz CPU.

I'd like to reinstall the 1.25 GHz G4 CPU - just looking for info on the capacitor info on this CPU upgrade.