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Dead Amstrad PcW 9256?

squelch41

New Member
Joined
Jul 20, 2020
Messages
2
Hi,
I got a PcW9256.
I got it to boot once into locoscript but it just seems to have died.
Originally, if I turned it on with no disc would produce 3 beeps after a few seconds (which is normal)

However, now I get a white screen and the disc spins but there seems to be no attempt to load and I don't get the three beeps to indicate bad disc.

I get the sync pulses and the video signal on the video connector.
I have tried taking the system board out and powering it from a 5v power supply but same problem.

Clock signal on the z80 is fine and steady at 4MHz. I can see activity on the data bus and address lines.
Reset line behaves normally.
No chips get hot.

1 capacitor had leaked but it was on the 12v line and I have replaced it - unsurprisingly no difference.

Jumper is set correctly for 256k ram.

Can anyone help point me in the right direction?
 
Is it normal for the IRQ pin (pin 16) of the Z80 to be held low?

It briefly goes high as the reset signal is high, then drops and is held low - seems to imply the Z80 is waiting for an interupt to come?

It is connected directly to the gate array with just a pull up resistor a far as I can see from the schematic.
 
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