RCA CTC 120, weird tuner issue

[old_tv_nut]

The ringing is probably due to a mistuned IF coil, perhaps a sound trap that's tuned somewhere in the video band instead of at sound frequency. No way of telling for sure what it is without the proper alignment gear.

[MRX37]

Originally Posted by old_tv_nut

The ringing is probably due to a mistuned IF coil, perhaps a sound trap that's tuned somewhere in the video band instead of at sound frequency. No way of telling for sure what it is without the proper alignment gear.

Given I had to adjust pretty much EVERY tuning slug in the IF section because I had to replace 2 that crumbled...

But, which one would be the cause? L304? The 4.5 trap? Something in the audio section?

[old_tv_nut]

Originally Posted by MRX37

Given I had to adjust pretty much EVERY tuning slug in the IF section because I had to replace 2 that crumbled...

But, which one would be the cause? L304? The 4.5 trap? Something in the audio section?

I could not, would not, make a guess. The real answer is to get the necessary test gear and do it right.

However, if you promise not to blame anyone but yourself if it gets worse, you could try more very slow random adjustments, and see if there's one that strongly affects the ringing.

Edit: not anything in the audio section.

[vol.2]

Originally Posted by old_tv_nut

The real answer is to get the necessary test gear and do it right.

Just for my own edification, what is the proper test equipment (other than a scope and a multimeter)?

[MRX37]

You could check out Shango066 on Youtube. he's done videos on IF alignment.

What I might do, some day is mark where the 4.5 trap is set at, and try adjusting just *that* coil and see what happens. My suspicion is the 4.5 trap is adjusted into the audio band.

[old_tv_nut]

Originally Posted by vol.2

Just for my own edification, what is the proper test equipment (other than a scope and a multimeter)?

A sweep/marker generator.