CPC6128 white screen of death?

[blahjedi]

(at least, it looks white on my monitor)

First time trying to fix a CPC and I'm somewhat stuck with which direction to go here. CPC6128, powers up ok but gets the white (or is it yellow or grey? My monitor makes it look yellow) screen of death and nothing more. Voltages to the Z80 and a handful of the RAM chips I've checked sit at 5v, have also tried swapping the Z80 and ULA out for known good ones without any change. None of the ICs get hot, and the PSU/video cable I'm using work fine with my good 6128.


I don't have access to the test cart to allow me to use the RAM test, and I don't have an oscilloscope here I can use either unfortunately. Short of going shotgun and socketing all 16 RAM chips, what else can I do to try and narrow down what the likely fault is?

[Audronic]

@blahjedi


Where are you Located (Country) ?
There may be some one local who can help


Ray

[blahjedi]

Tasmania, Australia. Given I'm one of the few down this way who actively hunt/try to fix up these things it's unlikely there's many others around who can help here.. heh

[CraigsBar]

Tasmania, Australia. Given I'm one of the few down this way who actively hunt/try to fix up these things it's unlikely there's many others around who can help here.. heh

Do you have an eprom programmer? If so you could just remove the rom on the board, replace it with a socket so you can put an eprom with the ram tester burned to it in there.

Sent from my ONEPLUS A3003 using Tapatalk

[blahjedi]

Do you have an eprom programmer? If so you could just remove the rom on the board, replace it with a socket so you can put an eprom with the ram tester burned to it in there.

Sent from my ONEPLUS A3003 using Tapatalk

I absolutely do. Will take a look into this - thanks!

[CraigsBar]

I absolutely do. Will take a look into this - thanks!

http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/quick-and-dirty-ram-test-for-cpc/msg106676/#msg106676 for the lower rom.

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