My A4000D died

[voyager]

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,

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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?

[cosmicfrog]

[8bitbubsy]

Desolder the RAM sockets and check for any corrosion, bad vias or traces. Also, could you take a picture of the motherboard? Maybe some of the electrolyte or battery acid (if any) has grown further and attacked something, even though you cleaned the vast majority of it.

Just trying a newer PSU doesn't mean the PSU is automatically good. Measure its voltage lines under load.

[8bitbubsy]

Any new on this? It's sad when Amiga hardware dies!