Thread: My A4000D died
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Old 21 February 2012, 19:23   #1
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My A4000D died

It’s a sad day today my A4000D died.
After spending so much time on her, it was a very abused miggy with leaking caps all over the place I actually feel quite sad.
I was running a whdload demo, I aborted it with F10 and noting.. Did a A+A+C reset and still noting.

So I turned her off and on again and I got a yellow flashing screen. It was working beautiful before no strange behavior at all.

Found a post from Alex,


Yellow on an A4000 is CPU Exception Before Bootstrap Code is Loaded

Now, what this actually means is that there is a memory assertion failure (usually Buster) - To test this is quite simple... Remove all RAM, including CHIP RAM...

Power up your system - if you are still getting a YELLOW screen then your machine is failing at Buster level - it is not latching the RAM access in - hence CPU has just had an unexpected exception - because of this you WONT get a green screen as POST doesn't get that far.

If you are getting a GREEN screen then there is a memory fault with either your CHIP RAM SIMM or latching F245 IC that locks in the CHIP ram from Bridgett - However I suspect that Buster / its latching F245 is most likely your problem.

Now, if Buster is in a socket, I would reflow the socket solder leads with a soldering iron (check for cracks or splits in the SMD 84way socket - replace if you have to). However if your Buster is soldered to the motherboard, then just touch up the PLCC legs with some no-clean liquid flux and a soldering iron and gently work my way arround.

I would test at this point, from here I would replace all the F245 Logic - start where the clock is and work your way around - test as you replace. I would also replace the caps if they have not been replaced.

I have replaced the PSU with a ATX one, a dirty hack but it worked fine, but still the same problem.
It’s a recapped board , cleaned with IPH etc, connectors are clean..

I have tried all the sims in the chipram bank , but all act the same.

Removing all the ram gives me a GREEN OR BLACK screen, with the old PSU, with the new PSU I get just a flashing GREEN screen.

Also I noticed that the hard disk spin-up is interrupted with the IDE cable connected.

I suspect the buster socket it’s a little wide on the sided, but putting some pressure on it did not help.
I Do have a hot air soldering station but I have not enough experience tot solder the buster directly onto the board. Well I can solder it to the board it’s the desoldering of the socked with hot air I don’t feel comfortable with.

I also don’t have a lot A4000 spare parts so I cannot check the cpu card etc.
Is there anything els I can try?
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