Hello, I recently purchased a CPC464 with the MC0099a tiny motherboard. When I switch it on it get a faint garbled noise through the speaker and a white screen with zig-zag black bars across it. I tried replacing the z80 and also tried piggybacking some more ram to no avail. Does anyone have any ideas what could be wrong ?
Thanks in advance. Antony.
Hi Antony.
Do you get a series of beeps if you hold the DEL key down?
Quote from: antpant7 on 11:47, 06 February 22
Hello, I recently purchased a CPC464 with the MC0099a tiny motherboard. When I switch it on it get a faint garbled noise through the speaker and a white screen with zig-zag black bars across it. I tried replacing the z80 and also tried piggybacking some more ram to no avail. Does anyone have any ideas what could be wrong ?
Does not looks good to me.
If you have a voltmeter, can you check that you have proper 5V, then that the Z80 reset line (pin 26) is high.
If the reset stays low, then you likely have a dead pre-asic.
I had the same screen with a dead rom.
Don't take my word though, cause could be many other issues.
Quote from: gerald on 12:13, 06 February 22
Does not looks good to me.
If you have a voltmeter, can you check that you have proper 5V, then that the Z80 reset line (pin 26) is high.
If the reset stays low, then you likely have a dead pre-asic.
Hello. I checked for +5v at pin 11 and Pin 26 both reading high. I do have a donor board (MC0044D) with a spare 40009 rom on it. Do you think that is worth a try ?
Thanks
Antony Myers.