WELLS GARDNER 4900 SERIES

NO BLUE - Broken solder connection at collector of Q403 on neck board - not visible as the connection was cracked under the solder pad.  Indicator was the absence of collector voltage (apprx 140 VDC)

PICTURE PRESENT ON BOTTOM, NOT ON TOP - Q302 measured shorted in circuit but not out of circuit.  Found diodes D302 and D303 shorted.

PICTURE MISSING ON TOP, only 3 inches or so visible below center line  - C310 10uf@100VDC

MONITOR DEAD, FUSE OPEN - Q303 shorted, R317 open - replace.  Also check large resistor (10 watt) mounted on heatsink - 3.3 ohms

HIGH VOLTAGE, NO DISPLAY - Open solder connections to the 2.2 ohm resistor near the small 4 pin plug on the CRT socket board.  Indication is that there is no filament display in neck of tube (orange lights inside neck).

Ripple drifting up through entire picture; sides of picture and images wavy.  Shorted STR381 regulator IC; B+ was running at around 145 volts.  Yes, and the monitor also had a failure in the shutdown circuit; it should have shut off as the B+ rose above 127 or so.

HANATREX MC 900

DEAD MONITOR, FUSES OK - Horizontal output transistor measures short to ground in circuit, ok out of circuit.  Ditto the damper diode and regulator device on the left (as seen from the rear) heatsink.  Located shorted to ground flyback winding feeding collector of horizontal output.  Diagnosed bad flyback, since shorts went away when FBT was removed from board.

G07

Monitor screen black but high voltage OK

Monitor had high voltage, no display. Filaments in CRT were not lit. Checked continuity between pins 4 & 5 of the flyback; that winding is the source of the filament voltage. Windings checked open - I figured the flyback was bad.
I started to unsolder the flyback and noticed that it was mounted at a slight angle to the PCB. After removing the solder from pins 4 and 5, I realized that they were not quite touching the solder pads; that is, they didn't protrude all the way through the holes.
I checked the continuity of the pins on the FBT itself and it was ok. I removed and reinstalled the FBT properly and monitor worked fine.
The only thing I can conclude is that the flyback was misinstalled at the factory (it looked totally original) and those pins made just enough contact to work for all these years, but over time and with moving the game the tenuous connections finally worked loose.

Pic flashing with blue going on and off - re-solder header pins on main PCB where the video input plugs in

Pic dim, shrunken all 4 sides - b+ at point B1 on board only 90 volts should be 120 - change X902 even though it tests good in and out of circuit

No green - bad X104 on main PCB

WG 7000 

IMMEDIATE SHUTDOWN
Source:RGVAC

Typically C57 being out of tolerance will cause it to shut down, but considering you've done the cap kit, look in the high voltage shut down circuit, D10, D12 and associated circuitry, including the caps you just installed, if they are ok, turn the HV shutdown adjust down (pulling 1 side of D10 out will bypass the shutdown circuitry, turn the HV shutdown first), also check C36.