Heathkit SB-104 - Display Circuit Board

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Display Circuit Board
TROUBLESHOOTING CHART
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X-RAY VIEW
SYMPTOM
In one digit, one segment
brighter than others.
One segment will not light.
Display will not light.
Display incorrect.
(Shown from printed side)
POSSIBLE CAUSE
The associated segment driver
IC.
1. Defective display tube.
2. Associated segment driver
I C.
3. Tube pin mounting sockets.
1. 5V or 180V missing.
2. Segment driver.
3. Display tube.
1. Signal from counter board.
2. Wiring error between counter
and display boards.