I’m Back! Pilot TV37

[Chris K]

Originally Posted by Electronic M

Yes you can. Granted on the Motorola if you have a good original ballast (2 of my 3 setsdo IIRC) it's not needed as the ballast should provide a soft start. On a set with a modern replacement ballast the TVS diodes and a thermistor are a good idea.


On my set IIRC the vertical linearity pot was bad. If there are any mica caps in the vertical (or outside of the tuner/IF system) change them. Micas in the sweep circuits tend to be under more stress and die young. If you haven't changed off tolerance resistors in the vertical yet that's definitely something to do. If those suggestions don't help voltage measurements against the schematic may reveal the point of failure.
I did run mine up to 115V on the variac without a bulb once I had it recapped and it was fine...Granted I would ramp it over the course of a minute for safety.

Also I haven't heard of this on Pilots before, but on the Motorola's where the HV is 2-3x that of the Pilot sometimes the octal sweep sockets arc through and create problems that are challenging to diagnose if you didn't expect that possibility.

Here's what it looks like at this point. Tom, these little capacitors I described as pea pods, do you know if they're mica?

[jr_tech]

Could you post a photo of a “pea pod” cap, please?

jr

[Electronic M]

Originally Posted by jr_tech

Could you post a photo of a “pea pod” cap, please?

jr

Yeah. I don't remember anything of that description. A pic might fire some neurons.

[Chris K]

Originally Posted by jr_tech

Could you post a photo of a “pea pod” cap, please?

jr

Here you go

[jr_tech]

Ah! the “dogbone” caps are ceramic, and mostly last forever.

jr

[Chris K]

Originally Posted by jr_tech

Ah! the “dogbone” caps are ceramic, and mostly last forever.

jr

Good to know. Just ordered a complete complement of resistors. Will replace every one of them regardless of measured value. I’m going to get a full set of new tubes as well…just to be sure.

[Chris K]

Originally Posted by Chris K

Good to know. Just ordered a complete complement of resistors. Will replace every one of them regardless of measured value. I’m going to get a full set of new tubes as well…just to be sure.

Here's an update: What I thought was a vertical deflection issue was not. Somehow, the CRT had been rotated 90 degrees so the vertical was fine...the horizontal was the problem!

Replaced the horizontal amplifier and oscillator tubes but it had little effect. The trimmer cap screws for horizontal size and linearity were seized so I removed the trimmer from the bottom of the chassis, disassembled and cleaned it. When I applied power, this is what I got. Obviously a very long way to go but I have something that resembles a full deflection screen. The Littlefuse diodes came today. Does anyone have any info on how to install one to protect this rare working 3KP4?

[Electronic M]

Originally Posted by Chris K

Here's an update: What I thought was a vertical deflection issue was not. Somehow, the CRT had been rotated 90 degrees so the vertical was fine...the horizontal was the problem!

Replaced the horizontal amplifier and oscillator tubes but it had little effect. The trimmer cap screws for horizontal size and linearity were seized so I removed the trimmer from the bottom of the chassis, disassembled and cleaned it. When I applied power, this is what I got. Obviously a very long way to go but I have something that resembles a full deflection screen. The Littlefuse diodes came today. Does anyone have any info on how to install one to protect this rare working 3KP4?

Install the diode in parallel with the heater of the 3KP4.