G05 Deflection Board Repaired

From: Mark Spaeth <mspaeth_at_arcade.ne.mediaone.net>
Date: Mon Dec 20 1999 - 00:21:58 EST

Just wanted to announce my first successful G05 deflection board repair.

The Victim:
My AD that ran 24/7 for about 18 months solid...

The Symptom:
No V deflection (and the board was hosed too)...
Spot killer on...

The Cure:
1. Replaced the chassis transistors (of course)
   Both V deflection transistors were shorted, but that didn't help

2. Check all diodes, and transistors
   Hmm... they all look good...

3. Check resistors...
   Damnit, one of those big 2 ohm 7 watters was open!
   Cut 2 1 Ohms off DCmodded pacman boards... voila...

When it came back up there was a lot of ripple on a vertical 1/2 of
the screen, so I swapped transistors again (used ones from old
cap kits -- Hi patty ;) and it cleared up...

How often to those high wattage resistors fail? I've seen them
replaced on quite a few deflection boards now, but wouldn't expect
them to be a major failure mode...

--MS
Received on Sun Dec 19 23:23:23 1999

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