bstnguy
Well-known member
Symptoms: Frequent D6 ROM error on boot up, horizontal jailbars in backround graphics(NOT through sprites)
Tests: Fluke 9010a bad bus, bad D6 signature.
EPROM reads good on burner, inspection of socket yields two bad pins. Replace socket, replace EPROM, good bus, good D6 signature, game boots up reliably.
Checked inputs on G2 and G7 74LS153 on main CPU (middle board), no activity on G2-4. Checked inputs on G3 74LS374, all good. Socket and replace 374, jailbars gone.
Thanks HudsonArcade for some guidance!
Tests: Fluke 9010a bad bus, bad D6 signature.
EPROM reads good on burner, inspection of socket yields two bad pins. Replace socket, replace EPROM, good bus, good D6 signature, game boots up reliably.
Checked inputs on G2 and G7 74LS153 on main CPU (middle board), no activity on G2-4. Checked inputs on G3 74LS374, all good. Socket and replace 374, jailbars gone.
Thanks HudsonArcade for some guidance!