Green Screen When Powered-up

[Wobble_master]

60Hz set.... maybe

@Wobble_master have You oscilloscope or multimeter ?

I have a multimeter and logic probe, I'm struggling with the schematics against the later costs down board saving board in mine. Has anyone got a basis diagram of the layout. 

[McArti0]

Internet not remember pinout ASIC3 AMS40226 

[Wobble_master]

Internet not remember pinout ASIC3 AMS40226 

Found the pin out for the ASIC

[McArti0]

Try found 4MHz Clock signal on Pin6 CPU and 1MHz on WAIT signal on PIN24 CPU with duty 25%

[Wobble_master]

Try found 4MHz Clock signal on Pin6 CPU and 1MHz on WAIT signal on PIN24 CPU with duty 25%

I think I'd need an oscilloscope for that, all I have is multimeter and logic probe. 

Thanks 🙏 

[McArti0]

Add photo this multimeter and logic probe

[Wobble_master]

Add photo this multimeter and logic probe

[]

Hopefully you can see the image?

[McArti0]

Preview and  Click or drag files here to attach them.

[Wobble_master]

https://www.dropbox.com/scl/fi/x1dl6ohv0tlx9k69gg3pv/IMG_4732.jpg?rlkey=7s184du3vxe1xkmfka2ab0me5&st=g3o9b06f&dl=0

Image of the Meter and logic probe

[Wobble_master]

Preview and  Click or drag files here to attach them.

Got it, thanks 👍

[McArti0]

Ok use oscillophone.

Set speeker volume  louder.

Cross Pin1 expansion port (sound) and Pin16 CPU (INT) You should hear 300Hz sound.

Try this on Synchro Pin videoPort too (60Hz)

[Wobble_master]

Ok use oscillophone.

Set speeker volume  louder.

Cross Pin1 expansion port (sound) and Pin16 CPU (INT) You should hear 300Hz sound.

Try this on Synchro Pin videoPort too (60Hz)

Will give this a try tomorrow, also order this to help

[McArti0]

Its not help

Minimum is DPOX180H

[McArti0]

Ok use oscillophone.

Set speeker volume  louder.

Cross Pin1 expansion port (sound) and Pin16 CPU (INT) You should hear 300Hz sound.

Try this on Synchro Pin videoPort too (60Hz)

You only need one wire for this.

[Wobble_master]

Its not help

Minimum is DPOX180H

Is this just because its doesn't have a probe?  Will try you suggestion tomorrow. 

[McArti0]

DSO152 mini   2,5MSa/s 200KHz   ... You need 100-200 times more ...

[abalore]

Board fixed, it was a bad RAM IC

[abalore]

@Wobble_master but you at least should have been able to see the screen geometry, so don't discard the monitor is also broken. A 2x1 scam

[Wobble_master]

Board fixed, it was a bad RAM IC

Wow can't wait to get it back and have a play. Might not be everyone taste but I loved the Dizzy games.

[Wobble_master]

@Wobble_master but you at least should have been able to see the screen geometry, so don't discard the monitor is also broken. A 2x1 scam

I have no plans to get rid of the green screen as that will complete my 80's experience of having a CPC464 😊

[Wobble_master]

Massive thanks to @abalore for fixing my CPC board, just playing Bomb Jack 👌👌👌👌