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Old 19th Sep 2018, 11:09 pm   #50
high_vacuum_house's Avatar
Join Date: May 2003
Location: Rugby (home) and all over the country for work
Posts: 1,054
Default Re: Stuck on a BRC 1400!

Good evening,
I have had some success in getting the frame linearity correct. After changing all of the suspect capacitors and the PCL85 the frame linearity was still poor at the very top and bottom edges. The frame linearity main pot was still at its lowest resistance value end. I decided to try a lower resistance resistor in R117 position which is directly in series with the pot. On switch on I had frame roll though once adjusted this gave me more control of the main linearity pot and was able to get it right with the pot wiper nearly half way down its track. Once the height and picture shuffle rings were juggled I was able to get a cracking well displayed test card C.

If you are still needing a bit more height I found that changing C82, a 0.1uF blue/white cap on one end (heater decoupler near to the frame fault take off) helped a little and gave me a bit more height.

Christopher Capener
A proper radio is one that needs to be moved with a wheelbarrow !!
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