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Old 12-16-2018, 05:02 PM
Kevin Kuehn's Avatar
Kevin Kuehn Kevin Kuehn is offline
Workin' Late Again
 
Join Date: Jan 2011
Location: WI
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Quote:
Originally Posted by AlanInSitges View Post
Yes, I'm pretty stoked! PAL horiz frequency is pretty close to NTSC 15,625Hz, and just found what I guess is the intensity control on the cathode of the CRT - I'll lower it, good suggestion.

According to the service manual:



I can't find anything resembling a frequency adjustment in the horizontal oscillator circuit - could it be something besides a potentiometer?

It seems to me that R52 and R53 are the most likely causes of the off frequency, along with C101. That's what I'll check next.
The horizontal freq is derived by a divide by counter(CD4013) driven by the color burst oscillator. There's a trimmer cap(C100) in series with the color crystal in the grid circuit of V6A that should allow some adjustment.

Before I'd worry much about the horz frequency I'd be looking for the cause of your vertical deflection collapse. Possibly a bad cap, connection, or tube in the vertical section. Possibly even the vertical height or linearity controls.

Last edited by Kevin Kuehn; 12-16-2018 at 05:07 PM.
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