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Predicta Holiday - First power up attempt
HI All,
Well, the XYL and I tried powering up the Predicta Holiday last night. Ramped the power up slow and got the tubes to glow. No sound or raster. Everything smelled and looked fine. Could hear a slight noise from the flyback and up at the CRT, a regular beat. Looking at the troubleshooting chart it says power supply is the most likely culprit. So I pulled the HV can off and measured the flyback for resistance. With the can off I can see a drip underneath the flyback. 5-D, 11.6 Ohm out of expected 12. 4-3, 10 Ohms out of expected 13 3-B, 8.6 out of expected 11 L17, spot on, 1.7 ohms Although it says on the schematic not measure between 5 and the HV output, it gives an expected measurement of 385 ohms. I figured that the do not measure was for older VTVM's, so I checked it anyway, 366 ohms. So the top coil seems good, lower coil a little low in resistance. Shorted turns? When we pulled the HV rectifier tube, it was completely cool to the touch. With the really low filament voltage I am not sure how warm it should be. So, any suggestions where to start? Jonathan |
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