randomly hangs - except the mouse moves

I have two problems here... First, my eMac (the ATI series, 1.25GHz G4) running Tiger 10.4.11 is hanging randomly. The mouse still moves, but the interface is completely unresponsive. All I can do is shutdown and reboot. No third-party hardware/software, and I can't reliably reproduce it.

Second, I tried to boot up on the Apple Hardware Test (1.2.2) disc, and it gives me an "Invalid Memory Access" error and dumps to an Open Firmware prompt. I understand that some PowerMac and PowerBook users have had this issue, and Apple released an update for AHT for those models. The error and the memory address given are identical to some of those reported errors; where can I find an updated AHT, and will it work with my eMac (since it looks like some versions are for particular Mac models)?

Thank you all.

Try Mactracker http://mactracker.dreamhosters.com/ to see if there's a link therefrom to get your AHT update. Does the Apple site not provide it?

Second, your eMac may be experiencing the leaking capacitor problem (the 'hanging' or 'freezing' issue), and you'll need to check the motherboard. There's a good deal of advice about that on this forum.

Thanks for the reply. I checked the board out and the capacitors do look a bit worse for wear... Most of them are at least bulging a bit.

Yes that is the sign the capacitors are on the way out unfortunately. Here is a discussion link on the problem:-


http://emacproblems.blogspot.com/



Here is a link to download the latest version of AHT 1.2.2:-

http://www.info.apple.com/support/aht.html

I have two 1.25Ghz eMacs....one had that exact same issue, a local Mac only new and used store was able to repair it by replacing the capacitors. Not a job for the faint of heart but it can be done by a knowledgable person who knows how to wield a soldering iron and can understand a board diagram.

WELL, soldered on some new capacitors. Checked everything out, and turned her on... And everything worked. For a while. Before I smelled something burning...... Shut it off; and the capacitors are fine, but one of the little black components beside them (sorry, don't know exactly what they're called) is burnt to a crisp. Ack.

And yes, I checked, all the new capacitors are soldered in with the proper polarity. So I made another post to see if I can find a non-working board comparable to mine so I can play around some more.

Hey, good on you for attempting the repair. Can you identify, or post a pic of the "little black component"? It's possible you could replace that as well.

it dawned on me it's a voltage regulator... sourcing from mouser, i'll have to wait for it to ship.

thanks!!good!

hughvane said:

Hey, good on you for attempting the repair. Can you identify, or post a pic of the "little black component"? It's possible you could replace that as well.
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Click to expand...

guruofgentoo said:

it dawned on me it's a voltage regulator... sourcing from mouser, i'll have to wait for it to ship.

Click to expand...

It could also be a limiting resistor. But anyway, you need to do much more than just replace that particular component otherwise you're going to experience more smoke.

Something is amiss to draw enough current to take out a voltage regulator, diode, limiting resistor, whatever it is. Time for a service manual and a good VOM.

Regards.

Leaky capacitors

Hello,
This is my very first message, because this problem prompted me to search for a Mac forum. Our family computer is a 2.4 Ghz iMac running Tiger, so you can estimate how long my eMac has been standing collecting dust.
Any way I want to resurect it because I always had a soft spot for the eMac, being the G4 with most bang for the buck in my opinion.

Regarding the leaky capacitors, I have them as well bulging and all and ozing brown stuff. But not all of them. So when replacing capacitors you need to replace them all. because even if they look good they could be shorting out. Perhaps that is the reason why you are frying the regulator now. I counted 13 in all. (Still need to buy them.)

I also have some questions:
My capacitors are black with a copper line on the negative connection.
(I guess negative but I am slightly confused becaue from my old time experience with electronics, think ham radio's not high tech, the positive side is marked.)
Further more on the PCB there is a rounded and a square solder pad. I deduct that the square one is again negative or ground. Can some one confirm that?
Second question: Where to buy, with out getting the same vendor, and should I up grade them to a higher voltage? These ones are rated 6.3 volt

Finally some more about the problem description: picture frozen mouse works. I have that as well, but in extra I get horizontal lines through the image. And if you boot the Mac up with Norton Works, it allows you to do everything with that program. Also you can install the software again if you boot from the OS on DVD. Which in my case resulted in some moments of false hope before I decided to open my eMac.

Hugo

I have the same problm with the freezing and have the 1.25 eMac. I was wondering if its worth it to call apple on this. They've been great before with my Pod Nano 2nd gen and MacBook repacing thing in/ourt of warrenty before. Would I have better luck over the phone or in person? Or should I just try a local apple dealer?

I took the back case and emi shield off the eMac and found that there are about 5 leaking or swollen caps. I'll upload pictures as soon as I can get my camera hooked up to my Macbook (luckily no problems with it!)

Try your Apple dealer Chimpur. There was a general recall of 1.25GHz eMac G4's falling within certain serial numbers, but that ended some time, possibly years, ago.

If you cannot tackle the job yourself or have a friendly techo who wants to learn, not worth the cost of replacement alas.

I did call my local apple dealer and they said it'd be $500 to fix! i said what about the repair program and they said it wasn't worth there time trying! I might take a trip to Toronto and see one of the Geniuses there. I'm really upset that I got sold a lemon like this!