I got only some black and white jailbars...
Can you make a photo of this?
no signs of activity when pressing the keyboard...or beeps.
And if pressing the reset? Normaly it is make a little jump in the screen while the Nick chip reseted.
I have System clock, z80 clock, video clock but no z80 reset signal or 1 Mhz Dave clock...
These are checked with scope?
Z80 reset are low or high? There is any change if you press the reset?
The two +5V and the +12V power lines checked?
If the machine are with bad Philips capacitors, the I suggest try to replace these.
Least C9, C10, C11, C12 (power part), and C4 at reset circuit.
Is Dave subject to age decay ?
Not know. But there is some know story of some machines which are not stored in a room, on a normal temperature. Stored in attic, shed, cellar where extreme low or high temperature possible, then the machine dead with a Nick or Dave fault
Or there was a bad batch of EP64 ?
At the production start many problems with chip qualities, then possible these more sensitive for storage conditions.
And is there a way to find spare Dave chips somewhere ?
Just if you found another machine with a dead Nick and working Dave...
But there is a FPGA project, I don't know, but probably possible will produce replacement chips?
