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IIci no soft power off
Posted by: joshc on 2009-05-04 23:51:26
Recently acquired a IIci, and it appears to work quite well, but there is one problem that is really annoying me. When I choose to Shutdown, the dialog saying "It is now safe to turn your Macintosh off" appears, with only a Restart button. Problem is, the IIci has the push-button switch at the back, and pushing that again has no affect. Pressing the Reset button on my ADB Keyboard powers the machine on, but pressing it again to shutdown has no affect. I thought it could be related to the software, since it was running 6.0.7, so I upgraded it to 7.1, same thing. So far, I have just been switching off at the mains, which isn't very ideal to say the least. Any ideas?
Posted by: equill on 2009-05-05 00:01:03
Welcome to the Sufferers From IIcx/IIci/Q700-PSUs Club.

viewtopic.php?f=8&t=6362&p=65705

viewtopic.php?f=8&t=2705&p=29555

viewtopic.php?f=8&t=1792

de
Posted by: joshc on 2009-05-05 01:09:06
I thought it could be capacitor-related, especially since sound is also not working (the soft power off issue is more annoying, however). I have now disassembled the IIci so I can take a good look at the logicboard. On further inspection, I noticed four problem areas:

PRAM battery looks a mess, obviously needs replacing: (I already have the replacement battery)



This doesn't look too great:



Some minor mess here:



And here:



In terms of capacitors, they physically look good, no goo or bulging in sight.

Seems like the best thing to do is wash the logicboard, put in the new battery, and see what happens.
Posted by: equill on 2009-05-06 08:56:23
I'm not so sanguine about the MLB, either. Yes. The state of the battery gives one the cold horrors, to be sure an' all, but the cage generally and its connection to the MLB will need some rigorous work and checking. The case of the crystal, being probably nickel-plated, has patently not appreciated the alkaline effusion from the battery.

The 'no goo' part of your parting statement may be worth reassessment. The third and fourth MLB shots appear to show your use of a flash to take the pics. Is this so? Notice that the reflectivity of the lacquer differs, being much less in the fourth pic than in the third. Add the apparent brown stain in the same area in the fourth pic, and the total is definitely the need for a good wash, whether you use the dishwasher, a fire-hose or the spraybottle that I recommend. That is the preamble to recommending a complete recap with tantalum electrolytics as well as the wash. Whether or not it is so that there is goo on the bulk of the MLB, you are lucky that the large axial caps under the PSU have not alsp puked onto the board. There are not that many of the SM aluminium electrolytics, so replacement is an assurance of continued functionality when you get the PSU tamed.

Whether the associated caps of the audio circuit have visibly failed or not, you should also be able to rescue sound out as a result of the recap.

Best of fortune to you in the endeavour.

de
Posted by: joshc on 2009-05-09 03:47:07
Thanks equill.

It is having a bath right now (click the image for bigger version):



That's just water, a very tiny amount of washing-up liquid, and vinegar.

I gave the affected areas a good scrubbing. I tried vinegar on the battery holder, but can't seem to get the connections clean...hmm.
Posted by: Unknown_K on 2009-05-09 04:50:18
That battery holder needs replaced and most likely so do the capacitors on that board. You don't have the PS push button in the back in server mode do you?
Posted by: joshc on 2009-05-09 07:41:33
That battery holder needs replaced and most likely so do the capacitors on that board. You don't have the PS push button in the back in server mode do you?
No, the power switch was in the correct position.

I think you are right. Washing it achieved...nothing. I dried it with a hair dryer, took about 10 minutes to dry it completely. Just tested it with a new PRAM battery, and there is still no soft power or sound.

Two questions:

- What tools do I need for soldering on a surface mount PCB?

- Which components need replacing?
Posted by: Unknown_K on 2009-05-09 10:58:38
I would just replace all the metal can surface mount capacitors, the tools and how to do it was posted in a thread here a few days back I think by me.
Posted by: joshc on 2009-05-10 07:29:27
I couldn't find your thread, Unknown_K. But I did find an excellent website which has videos and pages about the tools and how to actually do it:

http://www.curiousinventor.com/guides/Surface_Mount_Soldering

At the moment I cannot justify the cost of a good soldering station (such as a Weller), since I would only need it for this one repair. This is probably a fix I will get done one day, but not any time soon. Equill, thanks again for your help!
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