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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: amigamad on January 08, 2004, 11:30:58 PM

Title: a4000 cr motherboard revision d faults
Post by: amigamad on January 08, 2004, 11:30:58 PM

After puting a buster chip and roms in this a4000 cr motherboard that i bought for spares i thought i had been lucky as it seemed to be working fine.After messing around for a bit i realised sound was not working and it will not boot from internal or external floppy drive but every thing else works mouse keyboard and booting from ide port what i would like to know is am i right in thinking this is a fault with the paula chip .And this is not caused by leaking battery as this is the cr boared which had a lithium battery and not the nicad. :-?

Title: Re: a4000 cr motherboard revision d faults
Post by: Akiko on January 09, 2004, 12:31:39 AM

It doesn't necessarily have to be the battery that's leaking. Apparently capacitors can also leak acid resulting in very similar damage to the mobo
I've also recently bought an A4000 mobo for spares and it has exactly the same problems as yours.

This link might help clarify things- http://joj.home.texas.net/amigacap.html

Title: Re: a4000 cr motherboard revision d faults
Post by: amigamad on January 09, 2004, 02:37:58 PM

anybody got any other ideas before i try replacing the paula chip.

Title: Re: a4000 cr motherboard revision d faults
Post by: Framiga on January 09, 2004, 03:03:21 PM

Hi amigamad

with which CPU card?

A friend of mine, has those 4000CR mobo.
Due the lacks of the 50 Mhz quartz on the mobo, the CSMK2 doesn't works.

Ciao

Title: Re: a4000 cr motherboard revision d faults
Post by: amigamad on January 09, 2004, 03:10:41 PM

Using onboard 030 crystall is installed.
 :-)

Title: Re: a4000 cr motherboard revision d faults
Post by: Castellen on January 09, 2004, 06:55:48 PM

Do check the 22µF capacitors C317 (by pin 1 of CIA U300) and the other 22µF directly behind the parallel port connector for signs of electrolyte leakage.  See the other threads on A.org on this same topic.
As one of the CIAs interface some of the floppy control logic to the system's data bus, it's possible the damage is here.

It's also possible one of the CIAs is faulty, particularly if someone has tried plugging something "wrong" into the ext floppy port.

If you have a digital storage scope handy, you can check the system is polling the DS (drive select) lines from 0 to 3 on power up.  That'd be a good starting point.

Title: Re: a4000 cr motherboard revision d faults
Post by: Castellen on January 09, 2004, 07:03:19 PM

Forgot to mention, you could just try swapping the CIAs over since it's less than a two minute job (assuming you can SMD solder) which will prove if the CIA in question is faulty or not.

Failing that, replace Paula, and if still no joy you can start looking for PCB track problems.

That would be the less diplomatic, but fastest way to track the fault :-)

Title: Re: a4000 cr motherboard revision d faults
Post by: amigamad on January 10, 2004, 02:35:21 PM

Thanks Castellen

going to check the board again and see if any capacitors have leaked and i might even use the cia chips from my a600 as i know there fine . :-)

Title: Re: a4000 cr motherboard revision d faults
Post by: CU_AMiGA on January 12, 2004, 05:29:34 PM

@amigamad

I am sure you have already heard this before, but, i like your avatar very, very, very much. NICE!

Title: Re: a4000 cr motherboard revision d faults
Post by: amigamad on January 12, 2004, 06:33:15 PM

Quote

I am sure you have already heard this before, but, i like your avatar very, very, very much. NICE!

Thanks  :-)