bungy
Well-known member
Received a non-working G05-802, resistors R708 & R705 burnt to a crisp. Replaced them and a few other visible damaged resistors nearby with parts from a parts board. Also reflowed ALL header pins on both boards as per best practice.
Applied Bob Roberts cap kit with chassis mount transistors. Double checked transistor sockets and repaired broken wire on one. Tested in a known working game and got a white dot with spot killer off. So it has high voltage.
This is rev 5 board and already has jumpers instead of resistors at R100 & R101. DB100 also meters out good.
Tested transistors Q606, Q607, Q706, & Q707 out of circuit - Q706 was bad, makes sense since there were burnt resistors in the X amplifier circuit. Replaced with a good one and got the white dot again.
Tested transistors Q601 - Q605 and Q701 - Q705 out of circuit. Q703 and Q705 were bad so replaced with good ones (again in the X amp section). Got the white dot again.
Tested wire-wound resistors R620 (Y) and R720 (X) and both were wide open, hence no deflection in either direction causing the white dot. Replaced them with good ones and picture came up great.
Just posting in case anyone else might find it helpful.
Applied Bob Roberts cap kit with chassis mount transistors. Double checked transistor sockets and repaired broken wire on one. Tested in a known working game and got a white dot with spot killer off. So it has high voltage.
This is rev 5 board and already has jumpers instead of resistors at R100 & R101. DB100 also meters out good.
Tested transistors Q606, Q607, Q706, & Q707 out of circuit - Q706 was bad, makes sense since there were burnt resistors in the X amplifier circuit. Replaced with a good one and got the white dot again.
Tested transistors Q601 - Q605 and Q701 - Q705 out of circuit. Q703 and Q705 were bad so replaced with good ones (again in the X amp section). Got the white dot again.
Tested wire-wound resistors R620 (Y) and R720 (X) and both were wide open, hence no deflection in either direction causing the white dot. Replaced them with good ones and picture came up great.
Just posting in case anyone else might find it helpful.