Diagonal Lines on RF Output

[old_tv_nut]

Stripes only on the RF output does not sound like a failing power supply. Maybe RF interference from the power supply or some other VCR or piece of gear.

Time to do a process of elimination. Swap out the output cable(s) for another one(s) to check for bad shielding/grounds. Unplug other gear one by one to see if the interference goes away. (Don't just turn them off, as the power supplies may still be running in standby mode.)

[Zenith26kc20]

I have seen that with some of my Betamax machines. Changing the RF cable usually helps. On some of them, it is not possible to eliminate them. On those I use a RF modulator.

[Ed in Tx]

Sometimes one or more RF switching diodes or transistors that pass signal from the ANT-IN to the VCR tuner and select between Antenna and the VCR's 3-4 modulator when playing or recording, get zapped from a nearby lightning strike or somesuch. That can cause diagonal lines in the RF 3-4 output.

[Outland]

Originally Posted by old_tv_nut

Time to do a process of elimination. Swap out the output cable(s) for another one(s) to check for bad shielding/grounds. Unplug other gear one by one to see if the interference goes away. (Don't just turn them off, as the power supplies may still be running in standby mode.)

Just did this. Tried unplugging everything that wasn't the VCR, source, or TV. Lines remain.

Tried changing the cable. Lines remain.

Tried putting in an RF modulator instead of the VCR. Picture quality is awful, even by RF standards, but the lines are gone.

Look in the RF modulator for 1uf and .47uf electrolytic caps. They were notorious for failing and causing that.

I'll give this a shot.