I checked the main ICs and they are getting 4,9V too ...
So i should write a checklist:
So i'll go on with checking some things in the oric service manual and trying to shorten the cap C21 pins (thanks iss).- working power supply - OK
- 7905 and main chip voltages - OK
- ROM chip (i changed the ROM, but a had the same problem) - OK
- 6502 - reset pin - first low and then high - OK
EDIT: Shorting C21 - only a gentle noise and the result is the same.
EDIT 2: Maybe i should replace the C21 capacitor.
EDIT 3: I'm losing my temper and i want to throw this garbage to the wall ... i checked pins 14/2 of all DRAMs and all are different between 2.35 and 3,30V. they should be about 4V or am i wrong?
I searched and searched the net for a better failure documentation, 'cause i DON'T cut any lines. I don't know, what i should measure exactly and what to do now. Desoldering a 40 pin IC is a bit too difficult and piggy back isn't recommended here, i think.
Maybe the whole thing is not my cup of tea, i should stay with my Thomsons.