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Old 11-29-2013, 02:52 AM
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bandersen bandersen is offline
RCA 741PCS
 
Join Date: Mar 2009
Location: Chicago, IL
Posts: 8,808
I muddled my way through the alignment procedure over the last couple nights and things are looking better. I still get double peak sound on the dial, but it's louder and clearer. So is the picture.

The response curves for two of the stages were complete garbage. Way off frequency and the wrong shape. I was puzzled by a little jumper wire on the bottom of one can feeding from a lug into a little tube. That wire had been clipped off the IF can to the left.


Eventually, I found a section on this in the service info. I'm guessing some service tech encountered this problem and made an attempt to fix them.


I was able to adjust the wire and slugs in the right side coil and get a reasonable response curve. For the other I tacked on a 2pF (the closest I had to 1.5pF on hand) mica cap and got a semblance of the proper response.

I'll track down a couple proper 1.5pF caps and realign. So far I only found a ceramic C0G cap at Mouse for about $1.75 each.

Evan as is, the picture is pretty darn good.


I do have some horizontal jitter though. I still need to get a scope on the horizontal lock coil and go through the adjustment procedure. Hopefully that will clear it up.
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