Jon Raiford wrote:
> I am having one hell of a time trying to get my G05 to work.
> Here is what I have been through so far: When I first got the
> machine a couple months ago, I fired it up and it had no Y
> deflection. I installed a cap kit (including the chasis transistors).
> The problem was still there. I looked on the board, and there
> was one visibly fried resistor R610. Replaced it with no luck.
> Using my remedial skills, I managed to locate several dead
> components: R620, R610, Q603, Q605 (replaced in that order).
> I replaced them along with all of the 470 ohm resistors and all
> of the TIS98 transistors (I even desoldered and tested every
> resistor in the R600's). I also swapped the yoke wires and it
> was fine (just gave vertical deflection at that point). The pins
> in the AMP connector from the main board were falling out
> so I replaced them. When I replaced Q605 and tried it out
> (I couldn't find any other problems), R618 and R613 were
> killed with extreme prejudice. I verified that the voltages
> from the power supply were correct, and the game plays fine
> blind. The x, y, and z outputs tested good too (slight low
> voltage swings).
> What is the best way to track this down? FWIW, I don't
> have a scope to play with. Thanks for any insight!
OK, let's walk through this. First you had "one visibly fried
resistor R610". I wouldn't think that could even happen, but
I suppose if R620 opened and the yoke kicked back through
it that R610 could get damaged, along with Q603.
You then replaced "several dead components: R620, R610,
Q603, Q605". Well, there is Q603 and R620, and I can
believe the other two.
Once fixed "R618 and R613 were killed with extreme prejudice".
Hmmm, acts like the heatsink (or any lead) of Q606 is shorted to
ground? Or Q607. Or a solder short on ANY of the replaced
parts.
Another possibility is that either D606 or D607 opened.
This would crank all the currents up and cause just what
you have.
Received on Mon Jul 19 16:00:36 1999
This archive was generated by hypermail 2.1.8 : Fri Aug 01 2003 - 00:31:28 EDT