Slot-load iMac PSU Problem?

F

fatmark

Registered
My slot-load iMac has been good as gold since I bought it in Jan 2001. In March this year I replaced the hard drive with a 40Gb Seagate and moved over to Jaguar. A problem has recently developed where you can hear the hard drive head parking as the machine boots up. This happens many times but the boot up is otherwise OK. Once running, the problem continues for a little while and then goes away. If the machine is left on and woken from sleep, again it's OK.

My theory is that the +12V is taking some time to stabilise. The machine lives in a cold room and the problem has only started since the temperature dropped hear in the UK - a couple of weeks ago.

Anybody know how a hard drive decides to park? I guess it must be based on voltage rail levels. I think it's the +12V 'cos the machine is fine otherwise.

Anybody know anything about iMac PSUs and likely problem components? Might need to get the soldering iron out...

I shall start leaving iMac sleeping from now on but we've been suffering power failures recently so I don't really see this as a long term solution.

Any help much appreciated.


FatMark
 
Is this interfereing with your normal day-to-day operations? If not, what is the problem then?
 
arden said:
Is this interfereing with your normal day-to-day operations? If not, what is the problem then?
Click to expand...

Arden...i'm going to follow you from post to post and eventually find you ;) heh...you run rampid on these forums :p
 
You're right, i do. So?

How is that relevant to the topic at hand, anyway?
 
arden said:
You're right, i do. So?

How is that relevant to the topic at hand, anyway?
Click to expand...

it wasn't at all...just my feeble attempt at humor in a place where it doesn't belong...my fault if it came across in a different way than it was meant to come across, basically...i just was surfing..and blam... "last replied" was filled with your name, i thought it was just amusing how you were sweeping the boards...that's all, almost tactical...effecient...like a trained killer :D except in a good way...really, it was all in good fun :)

But on this topic....aquire a multimeter and test the 12v output...to see what it is giving you...it might be giving you too much or too little juice....possible when the machine shuts down it doesn't get to park the head all the way, and finishes the park when it starts back up again.... :)
 
Well, then... I pretty much understood your intent, but I would suggest that you keep the discussion on topic because I've gotten in trouble for leading threads astray before.

And no, for any mods reading this, I'm not trying to act like a mod!
 
Don't quite know what I've started here! But, getting back to the question in point...

It doesn't affect normal use, you're correct Arden. So why bother? Because I was hoping to sell my iMac when I upgrade next year and I wouldn't feel happy selling it with a problem like this.

T-K - the head parks normally on shutdown. I think you missed that the head parking noise occurs many times after switch on, not once. This can be anything upto 20 dodgy noises (maybe more) before the machine settles down. If it continues I can assure you I'll be getting my multimeter out! Managed to find an iMac service manual on the net yesterday so I have a clear idea of where to probe around.

Thanks for your input.


FatMark
 
fatmark said:
Don't quite know what I've started here! But, getting back to the question in point...

It doesn't affect normal use, you're correct Arden. So why bother? Because I was hoping to sell my iMac when I upgrade next year and I wouldn't feel happy selling it with a problem like this.

T-K - the head parks normally on shutdown. I think you missed that the head parking noise occurs many times after switch on, not once. This can be anything upto 20 dodgy noises (maybe more) before the machine settles down. If it continues I can assure you I'll be getting my multimeter out! Managed to find an iMac service manual on the net yesterday so I have a clear idea of where to probe around.

Thanks for your input.


FatMark
Click to expand...

Heh....well, glad you got the intent :) But moving on...It could possibly just be a bad hdd....i would try connecting another hdd and seeing if it works without the clicking and head parking noises, if so, then i would suggest that your harddrive is most likely just dying, if it does make the noises, well then..it's troubleshooting time. ;)
 
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