Quote:
Originally Posted by vortalexfan
Should I go back to the 59 uF cap?.
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I honestly don't know for sure. I was just suggesting it on a hunch because I struggled to get the vert linearity straightened out on my own set. It's not a straight forward linear amplifier.
Quote:
Originally Posted by vortalexfan
I wonder if the converter box issue has something to do with how sensitive the tuner and IF is to switchmode power supply noise? Because I know the converter box works fine with my Meck TV strangly enough but then it might be because that TV isn't overly sensitive to outside RF interference such as that put out by SMPS.
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If your tuner is so sensitive it's possible your TV's AGC circuit isn't working correctly. You could try measuring the AGC DC control voltage at point D on the Sams schematic. It should be around positive 1.5v with no input signal, around -4.5v with a strong signal. As a reference I've measured mine using an older DVD/VHS player with an RF output. The key being you should see some kind of AGC voltage swing dependent on signal strength. If that's not happening you could try forcing point D negative by putting some negative DC voltage across that point and ground(positive goes to ground). Maybe a couple 1.5v batteries in series. Just remember that going more negative reduces the gain of the TV's front end. In the end you really shouldn't expect these old set's to operate reliably in a noisy RF environment, such as switch mode supplies in their near vicinity.