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Old 02-28-2011, 10:44 PM
DaveWM DaveWM is offline
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philco with low focus voltage

max I can get is 4.8kv just short of focus. does the 66 meg every cause issues? it looks like it forms a voltage divider, goes from the focus rectifier to ground. Not sure how to check since I dont think any of my gear can go that low. there is also a 4.7 meg in series with the focus pin on the crt.
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Old 02-28-2011, 10:58 PM
ctc17 ctc17 is offline
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Check the disk cap, that resistor is 66kv at 6kv. Its a VDR thats there as arc and focus overvoltage protection. Remove it from the circuit and see if anything changes.

Sub the diode and check the disk cap.
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Old 03-01-2011, 03:59 PM
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Tomcomm Tomcomm is offline
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66M Resistor Cleaning

There's a 66meg resistor in the ctc2B that pulled my focus down. Checked its resistance with two DMM with 30 and 40 meg max. Both measured around 24meg. It was in there since '54 and gathered lotsa crud on its surface. I removed it and wiped it down with languor thinner. It now exceeded the range of my meters so I stuck it back in. Got expected focus voltage range so I assumed the cleaning worked. Lotsa luck..........Tom
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Old 03-01-2011, 09:50 PM
DaveWM DaveWM is offline
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thanks for the input guys, I will be checking it out later.
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