What does yellow screen mean?

Xanxi

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AmiBayer
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Hello.

My A2000 has crashed today, and since then i only get yellow screen on boot.

Even with every board removed, i still have yellow screens and no boot.

I have already reseatted/pushed every possible chip.

What could be the problem?

If i don't find a solution very quickly, i will throw it away like the crappy A4000 and definitly decommissioned. I will wait for the Natami and stay with good keyboard amigas like the A1200 and A500 which are way better even after 20 years.
 
Amiga Color Screens Scheme

Color Meaning
Red Bad ROM
Yellow CPU Exception Before Bootstrap Code is Loaded
Green Bad Chip RAM or fail of Agnus Chip (check seating of Agnus)
Black No CPU
White Expansion passed test successfully
Grey Turn on
Constant white Failure of CPU
 
Yellow screen means that there is a problem with the cpu - usually. Yellow is a hardware exception error so it could also have something to do with the Buster subsystem. Do you had any problems with battery leakage?
 
No this battery is like new.

Indeed, from previous experiences, i believe that yellow screen as something to do with either CPU or FAST Ram.
But it was doing this with only the naked mobo (except floppy drives).

BUT, finally, it is all back online and i am posting this on the A2000.

However, i swear it here before you, this is the last time for me.
Next time one of these fails me again, i will bury them all in the forest and keep only my A1200 until there is the Natami.
I am very very fed up to mount/dismount 40kg computers every two days.

Thanks for your help dudes.

---------- Post added at 23:12 ---------- Previous post was at 22:54 ----------

No!! It's crashing again...:Doh::Doh::Doh:
 
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 hope that helps.
 
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