A4000 boot error colours - Magenta?

[mechy]

Hi people,

Still fighting my A4000.
Occasionally it boots, and I'm fairly sure now it's to do with the CPU connector. I've got the voltages up nicely, so that should be ok.
I've cleaned and re-cleaned the CPU connector but it's so bloomin' difficult to get at, I still can't be sure it's clean.

Anyhoo, the symptom at the moment is a bright magenta screen on a cold boot. I know the CPU is basically working because if I remove the chip RAM, then it sure enough boots to a green screen.
Very occasionally I get a white screen.
Quite often I get nothing at all - just a dark grey screen as though the CPU is doing nothing.

I've tried with both the original 030 module and the CS-PPC, same thing on both.

All this time the Caps Lock light works as it should, no error codes or anything there.

Anyone got any ideas? Thanks if so!

are you sure the chip ram simm is correct?
double checked all the motherboard jumper? move them on the pins in case they are tarnished and making bad contact.
are you booting with floppy and or HD? i assume you waited long enough for the insert disk screen, it takes forever with no ide etc hooked up.
can the caps lock key be pressed on/off and the light responds still after say.. 10 times?

mech

[mechy]

I'll try the caps lock for longer when I get chance tomorrow.
It's the same magenta as when OS 4 boots, yes, but this is on a cold boot with just a floppy attached.

edit: it did work very occasionally earlier today but now it's just this magenta screen instead. The TV signal is displayed fine though.

Hmmm?  tv signal? is the 4000 hooked up using a A520 on the rgb port and then composite or are you hooking this to a big screen tv or some such via VGA?  
Most tv's will not take 15khz in from the 4000 and display it over the vga port-they expect 31khz in most cases(there are exceptions) but could this be the trouble?

Mech

[mechy]

Good job Spirantho. in all the A4000's i have had/worked on i have yet to have to resolder any custom chips due to bad contact. it was always something else.I guess you must of got a friday board(they were in a hurry to get to the bar after work) lol.
good job finding it. that was a tough one.

mech