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Old 7th Nov 2017, 11:56 pm   #23
FERNSEH
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Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: 405 colour on my Pye CTV

Played safe and connected a 2.7Kohm resistor across the existing 3.3Kohm frame timebase HT supply resistor. Sure enough there is a slight improvement to the linearity but mainly at the top of the picture. Also, there is plenty height available now before the picture cramps at the top. See second attachment.
Also noted is that the HT voltage is only 320 volts, and that's the voltage measured a the anodes of the two PY81 booster diodes. I reckon I should hit the frame output stage with the full 320volt HT supply.

DFWB.
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Last edited by FERNSEH; 8th Nov 2017 at 12:26 am.
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