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G08 Vector Monitor Guide
WARNING: Working with monitors of unknown operating condition can be EXTREMELY
dangerous. The Electrohome G08 is no exception. If fact, there are probably more horror
stories about this monitor than any other. Proceed with extreme caution.
Symptom: No picture; No fuses blow; No heater glow; All is quiet
Make sure everything is hooked up, and that the game boardset is operating correctly. If all that
checks out, you have most likely have problems in the deflection circuitry.
Symptom: No picture, but you can hear deflection chatter
If the heater is glowing, that means you have HV, and you should be able to get a picture. Adjust
the screen brightness to see if any lines are being drawn on the screen. Adjust the intensity and gain
knobs on the neckboard accordingly. If at this point you have a dot in the middle, or a line across
the screen, you have a problem in your deflection circuitry.
If the heater is not glowing, most likely you have no HV. Check for the presence of HV by
inserting an HV probe under the anode cup. You should read about 19.5 KV. If there is HV,
something is wrong with the heater connection or the tube itself (possibly a bad tube).
If there is no HV, check the voltages on the 10-pin connector on the HV unit. Be careful not to
short the pins together! The voltages are listed below:
Pin
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Pin 8
Pin 9
Pin 10
Description
Approx +2.8VDC
Approx +3.5VDC
-9.1VDC
+9.1VDC
GND
GND (heater)
+6.3VAC (heater)
+126VDC
NC
Approx 400 VDC
Wiggle, press or flex the 10-pin connector on the HV unit. Intermittent connections can cause the
HV to drop out. If this restores HV, reflow and resolder the HV header pins until the intermittent
connection is repaired. You may want to try replacing the connector pins as well.
If the voltages on the 10-pin connector look good, and there is still no HV, there is something
wrong with your HV unit. At this point, it probably wouldn’t hurt to try adjusting pots R933 and
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