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Power supply on dead G4 Quicksilver

Message #1 - Posted 2005/06/25 - Murray Anderson

Greetings

I have been given a dead G4 Quicksilver. It doesn't come on at all when the power button on the front is pushed. The Apple support site has details of the pin-out voltages for earlier G4 models (Gigabit Ethernet/AGP Graphics, etc) but not this model.

Can anyone help me to test the power supply, or give any other suggestion as to how to get it to work.

Many thanks.

Kind regards

Murray Anderson
Cape Town
South Africa

Message #2 - Posted 2005/06/25 - morenuf

Previously, Murray Anderson wrote:

Greetings

I have been given a dead G4 Quicksilver. It doesn't come on at all when the power button on the front is pushed. The Apple support site has details of the pin-out voltages for earlier G4 models (Gigabit Ethernet/AGP Graphics, etc) but not this model.

Can anyone help me to test the power supply, or give any other suggestion as to how to get it to work.

Many thanks.

Kind regards

Murray Anderson
Cape Town
South Africa

It could of course be a hardware problem like the power supply.

Disconnect all external peripherals but keyboard & mouse.

A few things to try (easy & no or low cost) that may help:

Some Mac models will not start with a dead motherboard battery. 3.6 lithium cell around $7-$10 USA dollars. Check for proper voltage & replace if questionable. Batteries can be found online or locally in US.

PMU is Power Management Unit which controls many aspects of startup and parameter RAM. It is a button on the motherboard near the battery (called CUDA on older designs and motherboard reset by some). Press it ONCE (too many presses may leave in corrupt state and drain the battery within 1-2 days instead of 3-5 years). Reboot.

Holding down Command, Option, P & R keys will reset parameter RAM (PRAM). This is probably also down already if you did the PMU reset above.

Would not hurt to remove & reseat anything you can on motherboard, RAM, hard drive cables, power cables etc. Sometime a poor connection or corroded one can cause problems.

Boot off a CD to bypass possibility internal hard drive is dead.

Hopefully one of these will help.

G'Day

Morenuf

morenuf@nobodyhome.com.invalid

Message #3 - Posted 2005/06/25 - David C.

morenuf <morenuf@nobodyhome.com.invalid> writes:

Some Mac models will not start with a dead motherboard battery. 3.6 lithium cell around $7-$10 USA dollars. Check for proper voltage & replace if questionable. Batteries can be found online or locally in US.

Radio Shack sells them.

-- David

Message #4 - Posted 2005/06/26 - Murray Anderson

Thanks for all the tips

A few things to try (easy & no or low cost) that may help:

Some Mac models will not start with a dead motherboard battery. 3.6 lithium cell around $7-$10 USA dollars. Check for proper voltage & replace if questionable. Batteries can be found online or locally in US.

There wasn't a battery in. I put one in, but still no luck.

Someone kindly sent me the pinout/voltages of the power supply unit. I tested the voltages as per the diagram, and everything seems correct.

New things that seem to be happening: when I originally switched it on, nothing happened; after testing the voltages, I heard a faint ticking from the PSU, and also saw a diode (D55) on the motherboard flashing about once a second. The fans started spinning, but the hard drive didn't, and nothing else happened.

Then the next time I switched it on, I noticed that the light in the front power switch illuminated when I pushed it, but went out as soon as I let go. If I hold the switch for about 5 seconds, the light stays on all the time, and then the fans switch off again.

Again, any advice would be appreciated. I still suspect the PSU is faulty, as the hard drive doesn't spin up even though the correct voltages are on the 4-pin power connector for the drive.

Thanks in advance.

Kind regards

Murray

Murray Anderson
Milestone Studios
15 Wicht Close
Tennant Road
Cape Town 8001

Message #5 - Posted 2005/06/26 - David Lesher

"Murray Anderson" <info@milestones.co.za> writes:

Again, any advice would be appreciated. I still suspect the PSU is faulty, as the hard drive doesn't spin up even though the correct voltages are on the 4-pin power connector for the drive.

PRAM reset?

A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433

Message #6 - Posted 2005/06/26 - Murray Anderson

Hi David

PRAM reset?

Maybe, but I don't even get the start-up chime....

Regards

Murray

Message #7 - Posted 2005/06/27 - daystartech

Make sure to hit the PMU button which is by the battey. Are you getting a light on the motherboard? If no...then it is possibly the Power Supply. Make sure to mimimize the system completely, removing everything possible. Without any RAM, you should get the single RAM error tone.

In addition to the power supply, it could also be the CPU card, or the Logic board. At this point, you are stuck doing component isolation testing (removing one part and testing with known good). The power supply if bad, can sometimes give out when stressed by the startup of the drives. Since you are getting some power, emoving the drives should at least allow you to get through the chime (successful CPU test), if it is a bad power supply.

Normally, if it a bad CPU card, you won't get anything at all.

Daystar provides mail in service and parts if you like at: http://powermacservice.com

Message #8 - Posted 2005/06/27 - Murray Anderson

Dear Gary

Thanks for the help.

"daystartech" <gary@daystartechnology.com> wrote in message news:1119881200.419648.61660@g49g2000cwa.googlegroups.com...

Make sure to hit the PMU button which is by the battey. Are you getting a

light on the motherboard?

Yes, D55 is shining.

If no...then it is possibly the Power
Supply. Make sure to mimimize the system completely, removing everything possible. Without any RAM, you should get the single RAM error tone.

No startup chime. Without RAM, still silent.

In addition to the power supply, it could also be the CPU card, or the Logic board. At this point, you are stuck doing component isolation testing (removing one part and testing with known good). The power supply if bad, can sometimes give out when stressed by the startup of the drives. Since you are getting some power, emoving the drives should at least allow you to get through the chime (successful CPU test), if it is a bad power supply.

I removed all the drives, still no chime.

Normally, if it a bad CPU card, you won't get anything at all.

I have an earlier (450 or 466MHz CPU card). Is that compatible, for me to eliminate whether the current CPU card is bad?

Daystar provides mail in service and parts if you like at: http://powermacservice.com

Thanks. I'm in Cape Town, South Africa. Does that still apply?

Kind regards

Murray Anderson.

Message #9 - Posted 2005/06/27 - Me

Previously, Murray Anderson wrote:

Hi David

PRAM reset?

Maybe, but I don't even get the start-up chime....

Regards

Murray

Repalace PRam Battery.........

Me

Message #10 - Posted 2005/06/27 - Murray Anderson

Greetings

"Me" <Me@shadow.orgs> wrote in message news:Me-260824.11395427062005@netnews.worldnet.att.net...

Previously, Murray Anderson wrote:

Hi David

PRAM reset?

Maybe, but I don't even get the start-up chime....

Repalace PRam Battery.........

I did, it measured 3.6V, still no startup chime.

Message #11 - Posted 2005/06/27 - Joe Heimann

Murray Anderson wrote:

Greetings

"Me" <Me@shadow.orgs> wrote in message news:Me-260824.11395427062005@netnews.worldnet.att.net...

Previously, Murray Anderson wrote:

Hi David

PRAM reset?

Maybe, but I don't even get the start-up chime....

Repalace PRam Battery.........

I did, it measured 3.6V, still no startup chime.

Is that voltage with the battery in its holder and the Mac not plugged into AC power? If not, and it was tested out of the circuit, the voltage reading will not be accurate. The battery recovers voltage very quickly when not under load, but may not have enough ability to supply current in use. The battery should read at least 3.3 V when in its circuit as mentioned above.

Joe

Message #12 - Posted 2005/06/28 - Murray Anderson

Dear Joe

"Joe Heimann" <heimann@ecs.umass.edu> wrote in message news:42c0a2a7@news-1.oit.umass.edu...

Is that voltage with the battery in its holder and the Mac not plugged into AC power? If not, and it was tested out of the circuit, the voltage reading will not be accurate. The battery recovers voltage very quickly when not under load, but may not have enough ability to supply current in use. The battery should read at least 3.3 V when in its circuit as mentioned above.

I didn't have the AC unplugged when I measured it, but I have now tested again, and it's still 3.6V in the Mac, without the AC plugged in.

Murray

Message #13 - Posted 2005/06/30 - Murray Anderson

Dear Group

Thanks to all those who offered advice. I eventually concluded that the power supply was fine, found a second-hand logic board, and everything works fine again.

Kind regards

Murray

Murray Anderson
Milestone Studios
15 Wicht Close
Tennant Road
Cape Town 8001

Tel: +27 (0)21-4617591
Fax: +27 (0)21-4654119
Mobile: +27 (0)83-2306940
Website: www.milestones.co.za

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