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Museum of the Game® & International Arcade Museum® Forums
Hello,
I have a K7000a Zenith built chassis that was dead. Blown fuse, shorted HOT, shorted voltage regulator. I replaced all and powered on momentarily to find that the flyback was indeed bad (arcing). That was expected. I had a donor k7000a chassis with the same flyback which I pulled and installed. The chassis was the 19" variety rather then the 25" yet the flyback part # is confirmed the same.
After installing I have high voltage (28k with HV probe) which seems proper for 25" tube. Fuse doesn't blow. HOT and voltage regulator both are good. B+ is at 130vdc tested at both the neck board P202 pin 3 and R301. According to the manual it says it should be 123vdc, but its not in shutdown. I have no heater voltage at the socket pins on the neck board. Therefor no neck glow and no picture on the tube.
Am I missing something? Power supply and horizontal circuits must be working for it to have HV. And I've tested the VR pins 1 and 4 are not shorted. HOT isn't shorted. I have not capped this monitor. Is it possible an electrolytic could be keeping this monitor from getting heater voltage? Is this just a cold solder joint or broken trace? Flow chart goes from No HV in one direction. To over 130vdc in the other direction. This is neither and after following the flow chart for no HV I've exhausted the normal culprits in which my tiny brain has the capacity to remember after 9pm on a Thursday evening.
Greater minds and fresher thoughts welcome.
Thanks
Blake