Green screen on startup A4000 intermitant?

[Ross1]

Hi everyone, My A4000 is occasionally giving me a Green screen on startup. I re-seated the chip ram and cleaned the contacts but it still happens about 50% of the time.
Any other causes that you can cum up with?

[AJS]

Well I found this?
The first colors you will see are shades of gray .. dark gray, middle gray, light gray, and then white. The RGB color values are 0x444, 0x888, 0xAAA, and 0xCCC, in that order. Colors shown before the four gray shades are artifacts from the original values in the custom-chip registers and do not indicate a failure.
The failure mode screen colors:
turquoise (0x0CC) (A1000 only) RAM failure in the Kickstart WCS
green (0x0F0) error in the lowest 256 bytes of Chip RAM. Possible causes, defective CIA-A IC or defective Agnus IC.
yellow (0xFE5) an unexpected processor exception before the appropriate system failure message was prepared. This could mean defective hardware or an attempt to access a RAM address where no RAM exists.
red (0xF00) invalid KickStart ROM checksum.
magenta (0xF0F) single-task or cold-start initialization failed.
Here is another interpretation of the Amiga boot colors:
RED   Kickstart ROM error   Two ICs in A1200, A3000, A4000
BLUE   Custom chip problem   Denise Paula Agnus
GREEN   RAM error   
YELLOWAbove problems combined       
LIGHT GREEN   CIA (U7/U300) problem   
BLACK   CIA (U7/U300) problem   If not booting
DARK GRAY   Hardware tested OK   
LIGHT GRAY   Software tested OK   
LIGHT GRAY   CIA (U8/U301) problem   Stops at gray, CIA defective
BLACK/STRIPES   ROM or CIA   
No video   R406 or R215 openVideo scrambled   Agnus or Denise defective   

[Ross1]

I replaced all the fast ram with ones I had laying around just to eliminate fast ram as being the problem (I dont have a spare chip ram) I get the green screen almost immediately when I power up (gray screen first for about one second) but it is not always as I said only about 50% of the time.
Its just strange.
Do you think I need to reseat something else?

[Thomas]

Check the clock battery. If it is leaking, the acid can corrode the motherboard beyond repair. Chip-RAM errors (green screen) can be caused by corroded conductors.

Also check the RAM socket. Could be a contact problem between the socket and the motherboard rather than between the RAM module and the socket.

Also try one of your Fast-RAM modules in the Chip-RAM socket. In the worst case a 4 MB module is recognised as 1 MB, but 1 MB is better than nothing. And if it works reliably with one of the Fast-RAM modules, you can find another 2 MB module as replacement for the faulty Chip-RAM.

Bye,
Thomas

[CLS2086]

Hi,
the 2Mb chip ram Simm support tends to fail.
Got the same joke here too. :-o

[Darrin]

Ross1 wrote:
I replaced all the fast ram with ones I had laying around just to eliminate fast ram as being the problem (I dont have a spare chip ram) I get the green screen almost immediately when I power up (gray screen first for about one second) but it is not always as I said only about 50% of the time.
Its just strange.
Do you think I need to reseat something else?

I have that problem with my A4000 too.  A quick flash of green on startup, but everything seems to work well.  I did buy it with battery damaged, but like I said, everything functions OK.  I have 2MB Chip, 16MB Fast and 64MB on the CPU card.

[Ross1]

I've replaced the battery and there is no corrosion. I will have to play around some more. Thanks all for your suggestions.

[MozzerFan]

@Darrin

You have a Deneb in your a4000, right?
If the rom-tags in the deneb-flashrom are succesfully installed, then a green screen appears at startup, just like you describe.

[Darrin]

MozzerFan wrote:
@Darrin

You have a Deneb in your a4000, right?
If the rom-tags in the deneb-flashrom are succesfully installed, then a green screen appears at startup, just like you describe.

Cheers for confirming that.  I always thought it was due to one of the expansion cards.

I've crammed a Deneb, a IDE Flyer, a Cybervision 643D and an Emplant into the Zorro slots.

My damn internal scan doubler broke down just before I left home so I guess I'll need an Indivision now.  :-)

[Ross1]

Well, the problem still persists, the strange thing is that if I leave it alone for about 2 min with the green screen showing it boots fine after that.