RCA CTC-16XH Smearing Issue

[old_tv_nut]

For pin 8 to be 177, the 100 v source that feeds it must be way too high. Check all the power supply voltages (but especially the 100 v source and R215, 47k 1W) and check pin 8 again to make sure you read it right.

Pin 7 should be 0vdc as you state. However, the 3.5 V on the schematic is not an ac meter reading but a scope peak-to-peak reading of the video waveform. AC meter reading will vary drastically depending on video content. The 30~ notation means the scope sweep rate is set to 30 Hz, so you see the two video fields as illustrated.

[Jon1967us]

Originally Posted by old_tv_nut

For pin 8 to be 177, the 100 v source that feeds it must be way too high. Check all the power supply voltages (but especially the 100 v source and R215, 47k 1W) and check pin 8 again to make sure you read it right.

Pin 7 should be 0vdc as you state. However, the 3.5 V on the schematic is not an ac meter reading but a scope peak-to-peak reading of the video waveform. AC meter reading will vary drastically depending on video content. The 30~ notation means the scope sweep rate is set to 30 Hz, so you see the two video fields as illustrated.

Great information. I really appreciate it.