View Full Version : 25NC37 chroma circuit


andy
04-22-2008, 09:12 PM
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drh4683
04-22-2008, 11:33 PM
Have you tried adjusting the burst amp plate coil with the hue control at mid rotation? Lots of times a slight touch up will bring the hue in phase to normal flesh tones. However based on your description of the color noise and loss of green, there are two very possible problems. I had a 20Y1C38 that had an open .01uf in the plate circuit of the 3.58 mHz osc. and caused unwanted noisy color. Also, if you have loss of green at one end of the hue range, if adjustment of the burst amp plate coil does nothing, check the 12pF disc cap in the plate circuit of the burst amp. They can open up and you will lose green. Lots of chassis' including the 25NC37 have identical burst amp circuits.
Absolute worst case scenario, you may have shorted turns in the burst amp plate coil. The problem is right around this area.

andy
04-23-2008, 01:17 AM
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andy
04-23-2008, 11:45 AM
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andy
04-23-2008, 07:01 PM
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andy
04-24-2008, 05:44 PM
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