1963 Zenith 29JC20 restoration

[Zenith6S321]

I put my glued together ferrite core back in its coil and put the set back together. Then I tried using the Sams IF alignment procedure. It did help some. The Sams procedure tells you to use a demodulator probe at points after the detector. This did not work for me. I used a normal scope probe and got reasonable waveforms. The Sams also shows three IF sweep curves but the alignment text only refers to two of them. After the Sams alignment procedure I did get rid of the ringing in the video but also lost color. I could not match the curves response in the 42-43 MHz range. I used the VA62 multi-burst and tweaked the IF adjustments to get more color signal frequencies through (3 to 4 MHz) and got the color back. But when looking at a channel 3 RF signal I got a noisy picture.

I looked through the R.L. Goodman Zenith Color TV service manual and found a more detailed IF alignment than the Sams. It showed similar sweep curves but its procedure referred to all of them. So my next attempt will be to use this alignment procedure. The procedure is general to cover several Zenith sets, including the 27KC20 (which has very similar design and is the successor to my 29JC20), so some test point designations require translation to use on my set. I am no whiz at aligning sets, but I am determined.

Dave