hatster
Member
Hi people,
Wonder if someone wouldnt mind helping me, spent hours on this now..
no LED on cpu board at all, Reset on Z80 is high (low, then high on powerup), clock is running (from xy timing board), if i press the diagnostic switch, i can see pin17 of the Z80 go low, then back to high when i release the button, but still no LED. HOWEVER: if i remove the XY timing board and powerup, the led comes on, if i remove any of the 2114 ram on the cpu or the security chip then powerup, the led comes on. If I remove the eprom card and powerup, NO LED even when diag pressed, same goes for XY control pcb.
Does this mean the cpu is running properly ?
(I replaced the Z80 and the 4x 2114 on the cpu board), and all 2114 on the xy control board.
Please Help before i go insane !
Wonder if someone wouldnt mind helping me, spent hours on this now..
no LED on cpu board at all, Reset on Z80 is high (low, then high on powerup), clock is running (from xy timing board), if i press the diagnostic switch, i can see pin17 of the Z80 go low, then back to high when i release the button, but still no LED. HOWEVER: if i remove the XY timing board and powerup, the led comes on, if i remove any of the 2114 ram on the cpu or the security chip then powerup, the led comes on. If I remove the eprom card and powerup, NO LED even when diag pressed, same goes for XY control pcb.
Does this mean the cpu is running properly ?
(I replaced the Z80 and the 4x 2114 on the cpu board), and all 2114 on the xy control board.
Please Help before i go insane !
