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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: fragment on January 12, 2009, 06:54:22 PM

Title: Some A3000 issues and questions
Post by: fragment on January 12, 2009, 06:54:22 PM

Hey,

I got a desktop A3000 some time ago and there are a some issues with it. Any help is appreciated :-)

Specs: 16MHz 030, 2MB chip, 4MB fast (8x ZIP chips), 1.4 roms, 100MB Quantum SCSI disk. Motherboard rev 9/02, daughterboard rev 7 (not 7/01 ??)

I suspect it has been overclocked although I don't have any software to verify it at the moment. The chip (7474) in U106 has been piggybacked with a 25MHz crystal oscillator. I didn't spot any other modifications. Do I need to revert the modification(s) if I want to install an accelerator later on?

The battery will be removed soon.. Hasn't leaked that badly yet.

The real issue is the PSU. The computer randomly runs from 1 second to up to something like 2 hours. The whole PSU shuts down, the fan too. Any ideas is it just the PSU getting old and dying or perhaps something else? Also, the PSU does not start if there is nothing connected to it but I guess this is normal behavior..

Thanks.

Title: Re: Some A3000 issues and questions
Post by: rkauer on January 13, 2009, 05:11:59 AM

 If it is working, don't fix it!

 For the power supply: open it and do a thorough clean, then test it again. If nothing changes, hack a AT/ATX unit inside the box and remember to set the tick jumper to video source.

Title: Re: Some A3000 issues and questions
Post by: dannyp1 on January 13, 2009, 01:41:03 PM

The problems you are having with the power supply sound like what was happening to my A3000T.  It would quit like yours.  Sometimes if I waited for awhile it would start again and other times if I gave it a little tap it would start back up.  I took it to a repair place here in town and they just called yesterday with an estimate of between $100 and $150.  It was a hard decision but I told them to fix it.  I probably wouldn't pay that much for a 3000d because they are more common and you can often get the whole computer for around that price.  

Dan

Title: Re: Some A3000 issues and questions
Post by: melott on January 13, 2009, 02:12:44 PM

It kind of sounds to me like the PSU fan.
My wife's PC had the same basic problem.
It was the PSU fan. If the fan wouldn't start then
the PC wouldn't start.
I would give the the whole PSU a good cleaning and
take the fan out and grease the bearing.

As for the accelerator, I also have an A3000d-16mhz.
I installed an A3640 card and it runs very nicely.

I know there was a hack that cut a trace on the 16 mhz
machines to make then 25 mhz. I don't know just what was
involved. The info is probably available on Aminet if you
are interested.

Mel

Title: Re: Some A3000 issues and questions
Post by: taunusand on January 13, 2009, 10:43:07 PM

Quote

melott wrote:
As for the accelerator, I also have an A3000d-16mhz.
I installed an A3640 card and it runs very nicely.

You don't have any heat issues?

Title: Re: Some A3000 issues and questions
Post by: dannyp1 on January 13, 2009, 11:07:18 PM

One of my A3000D's has an A3640 (revision 3.2) and so far it has been OK.  I have a stock low clearance heat sink.  I also have one of those ventilation fans that fits in an empty slot and blows air out of the computer.  I don't know if it makes a difference or not, but I had the empty opening so I'm using it.

Dan

Title: Re: Some A3000 issues and questions
Post by: taunusand on January 14, 2009, 06:11:03 PM

@dannyp1
Okay, I have an A3640 from my A4000, it has just been lying around since I got a 060 acc for my A4000. But I was afraid of using it in my A3000 because of heat issues, I know that commodores 040 cards get a lot hotter than 030.

But, you have convinced me, I'll try it. And of course add an extra fan ;-)

Thanks :-)