G3 B&W won't boot (no powerup)

Hi everyone,

Here is the scoop. I've only owned PC's but a guy at work was selling his G3 with the matching monitor for $30 so I took it.

I got it home tonight and the first thing I did was take out the old hard drive and put in an old 20gb I had laying around. I proceeded to install Panther on it when after it rebooted, the hard drive did nothing but chug for a minute then stopped. The whole thing just sat there with the Apple logo on the screen with the little clockwise turning star thing (sorry guys, I know this is painful).

Suspecting perhaps the install did not like the new drive (even though it did let me partition it) I unplugged it since I could not turn it off from the power button. I plugged in the old drive, hit the power, and nothing. no lights on the motherboard, no nothing.

I unplugged everything.... all RAM, video, hard drive, CD, etc. Still no go. Is it common that unplugging them when they're on toasts the power supply or mobo?

Any ideas? I thought maybe I could try a volt meter on the part that plugs into the mobo... I should get some DC readings from that even though its off right?

Hope you can help and thanks for reading
Kevin

Try making a copy of the install CD and see if that helps. You may also want to try and burn it at a slower speed and see if that helps.

Are you making sure to hold down "C" or "Option" and selecting the CD? Is it recognizing the CD at all?

Sorry, I must not have made myself clear.

When I hit the power button on the machine, I get nothing. No power whatsoever. Looking for anything else to try other then buying a new power supply or motherboard.

Do any of the lights light up?

No lights of any kind on the motherboard when the power cable is plugged in or when you hit the power button. No fans spinning, no nothing.

I tested the connectors for the motherboard that come from the power supply and a few of the colored wires registered 5 volts... I think one measured 3 volts. The others registered nothing.... I am not sure what all the colors are supposed to measure.

How about the battery on the motherboard? If the battery is dead, can that cause the system to not turn on? I haven't measured the voltage to see if its 3.6v but I will when I get home. From what I have read on the internet, there seems to be mixed explanations as to what happens when its dead. Some were saying it won't boot, but nobody defined what "won't boot" really means. the other posts say it boots up but you get a black and white screen and the date is reset.

Does the battery provide power to the front panel to allow the power button to work? This must be a little different from a PC where the power switch is wired right to the motherboard and as long as the motherboard is getting proper power and the switch works, it powers it right up.

Kevin

The battery shouldn't matter since all it does is keep the time clock going.

I would test your power supply if I were you. Disconnect it from EVERYTHING (do not plug in CD drives, etc when testing it). Take the power connector that goes into the motherboard and find the green wire. Take a paper clip and straighten it out, then bend it in half and put one end on the green wire and one end on any black wire (doesn't matter which one). Plug the power supply in and see if the fan is spinning. If so, your PSU should be fine. If not, then it's fried. Be careful not to touch the paper clip when you plug in the PSU since there is electricity going through it!

Thanks, I'll give it a try tonight. I assume I can use a PC power supply in a mac? the motherboard connectors are identicle.

As for the battery, I thought I read that it also had something to do with the power button.

On some Macs I have worked with like the iMac G3, if the battery is dead, it will not even turn on. Seen that on my Grape G3 333Mhz iMac. Battery was stone dead. Check the battery while you are checking other things. It can not hurt.

Live Wire said:

Thanks, I'll give it a try tonight. I assume I can use a PC power supply in a mac? the motherboard connectors are identicle.

As for the battery, I thought I read that it also had something to do with the power button.

Click to expand...

I have the G3 B&W and I have also noticed that the PSU Connectors are Standard, but I've read this:

The B&W G3 uses a power supply that's almost but not quite identical to an ATX supply. The lone difference is that the wire which supplies -5V on an ATX supply (pin 18) becomes a ground wire in the B&W G3. If you just plug in an ATX supply without any modifications, you'll short out its -5V output.

Click to expand...

I'd go for a Used One or a Refurbed One, Maybe One on eBay, like THIS one, or THIS one.

Hope this helps,
Nick

If that holds true, it sounds like an easy modification. You could snip the pin 18 wire from the PSU and jumper one of the other ground pins to pin 18.

I thought the Apple power supplies were 22-pin (the standard ATX PSU is 20-pin and the newer ones are 24-pin)...

I know my new ASRocks 939Dual-SATA2 Motherboard uses a 20 Pin connector (standard) and then has a seperate 4 pin plug for compatibility, Which I have to use for it to work, so, 20 pin is the Standard.

Nick

Yea, 20pin is the standard ATX connector... some will have that little 4pin extra jobbie as a seperate connector.

BUT!!

I came home today and it turned on! ***!!??? Well not that I am complaining, but it sucks that I don't know what happened. Also interestingly enough, I put my volt meter on the battery and measured NOTHING. I measured a regular duracell just to make sure the volts part of my reader was working and it was. Not sure what to make of that.

Anyway, I am installing Panther on the stock 12gb drive.... crossing my fingers.

Is your battery dead? I think I have to get one as my time displays the year 1956!!!

Nick

Well its not reporting any voltage, but then again my date and time are intact... I dunno what to think. Radio Shack sells the replacement for $15 so it might be worth it to get it replaced.

http://www.radioshack.com/product/index.jsp?productId=2104707&cp=2032056.2032141&parentPage=family

Well, Like I've heard someone say, If it's not dead now, then you don't have to worry for like 5 years, so eventually you'll have to replace it. Why not now?

Nick

Live Wire said:

Well its not reporting any voltage, but then again my date and time are intact... I dunno what to think. Radio Shack sells the replacement for $15 so it might be worth it to get it replaced.

http://www.radioshack.com/product/index.jsp?productId=2104707&cp=2032056.2032141&parentPage=family

Click to expand...

Don't know if you missed my post but I told you that some G3's that I have worked on were stone dead when the battery was bad. I would grab a battery and see what happens. Mine came alive. Shack is quite high. I found new ones on Ebay for a lot less but that was over a year ago.