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Amiga computer related discussion => Amiga Software Issues and Discussion => Topic started by: spirantho on December 01, 2006, 11:28:14 AM
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Hi everybody,
Just wondering again what could be wrong with my A600s (it's bugging me!).
Both of them have the same symptoms - power them on and they boot as normal until the Caps-lock LED lights up, at which point they lock solid.
Eventually (we're talking over an hour sometimes) the light will go out and the machine continues to boot, perfectly. Both machines work fine at this point.
Reset it (Ctrl-A-A) and it'll sit there again but for only usually about 30 seconds or so, sometimes a normal boot in fact.
Therefore, a number ways people may be able to help:
a) Can anyone say what I can do to fix it?
b) Can anyone say what the A600 is doing at this point.. what is it waiting for? I think it may be waiting for a power rail to calm down or something.
c) Does anyone have a breakdown of the KS2.05 ROM boot sequence?
d) Does anyone have a disassembly of the KS2.05 ROM?
I've tried with the Amigas fully laden and completely bare, same applies. It's not the HD or floppy detection because that comes after the Caps-lock light goes out I believe. Tried about 3 different PSUs, all of which power my A1200 and A500s perfectly.
I don't want to send them away to get repaired - no point. I've got enough working Amigas- I just want a working A600 too. :)
Any help gratefully received!
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I had two with same problems, 1 was actually completely dead. The other was like yours. Power on and LED on, ~30-60 minutes later booted fine for duration! Took them apart and nothing obvious. They sat for a few years and it made me sick since they were both in minty white shape. Finally contacted jean at Amiga center and he agreed to repair them both! A few short weeks I had the boards back! He said leaky caps were the blaim (near audio jacks) Seems to be quite common. Good luck.
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Hi,
Thanks for the advice - I took a gander at my capacitors and indeed two of them were a bit... fluffy. So, I've replaced them with some electrolytics I happened to have lying around. One of the caps was by the IDE, one by the audio. Replacing the IDE one meant the HDD now spins up before the lock-up, not after it... but I still can't get it to boot up when it should.
What I don't understand though is why replacing an audio filter cap such as C324 or C334 (the ones by the audio jacks) would have this effect. AFAIK the Amiga is waiting for the power to settle down, but those caps have nothing to do with the power rails.
I'm currently measuring C821 by the PSU plug and it's varied between 12.4V AC and 12.3V AC (starting at 12.4, gone down to 12.3)... I wonder if one of these caps has gone dodgy and I just can't see it.
I replace the other audio cap too, BTW... now C324 and C334 are both new electrolytics. Just in case, like....
I'd rather not go through the entire board changing all the caps just in case one is dodgy. :)
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(Edit!)
I thought I'd cracked it - but now it's gone back to being stupid.
The 12V caps read 12.6V when it was cold booting fine (after I replaced the two caps C821/C822) - now it's sitting waiting again they've gone down to about 12.4V....
Gaaaargh.. Very frustrating!
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This might be the most economic and least time consuming solution to fix your problem link (http://cgi.ebay.co.uk/Amiga-replacement-motherboard-A600-2-05rom_W0QQitemZ110063583145QQihZ001QQcategoryZ98928QQrdZ1QQcmdZViewItem)
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NOW it's fixed!
I asked Jean at Amiga Center if he could help and he told me to replace the capacitor near U14 - and it works! It's still not quite perfect, but a 15 second boot up is better than an hour!
BTW, I wonder why this thread is in the software issues forum? I must have clicked the wrong button or something, maybe a kind admin would move it to hardware for any future A600 owners...? :)
Thanks to all - especially Amiga Center - to whom you should all send your business from now on. :)