Philco 50-T702

[Crist Rigott]

I found a source for the HV capacitors.

I have most of the resistors and some of the film caps so I decided to replace what I could till the rest of my orders come in.

One of the first things I did was to clean up the mess that had happened from Philco's famous black tar/wax that had melted down to underneath the chassis. While I was at it I removed the phenolic pot board to aid cleaning up the mess and to clean up the pots. After several hours the mess was cleaned up and the pots were cleaned and fully checked for smooth operation with no bad spots. I then installed everything like before.

I then replaced some caps and resistors along the terminal strip behind the rear pots. I'll replace what I can with what I have for the time being.

[Crist Rigott]

I just got a used interlock power cord. It is serviceable, but a little stiff. Is there any way to "rejuvenate" the vinyl or plastic coating to make it a bit more pliable?

[Electronic M]

Originally Posted by Crist Rigott

I just got a used interlock power cord. It is serviceable, but a little stiff. Is there any way to "rejuvenate" the vinyl or plastic coating to make it a bit more pliable?

If you need to get the cord's ears over the rivets, soak it in boiling water.

[Crist Rigott]

Originally Posted by Electronic M

If you need to get the cord's ears over the rivets, soak it in boiling water.

Great idea! Anything to make the rest of the cord more pliable?

[timmy]

Does this set have seleniums, if so there could be one going bad as I had low b++ in one of my 7 inch sets because of a bad selenium rectifier. I replaced the 2 with 1n4007 diodes and cured the voltage problem. I had noticed one selenium was much hotter then the other so befor it shorted and and smelled up my house I changed them. Could be power supply caps too but I see your going over the whole chassis so I'm sure you will find the culprit. Does that set have an adjustable ring on the hv rectifier tube, if it has one that will affect the hv output.

[reichsrundfu]

Originally Posted by timmy

Does this set have seleniums, if so there could be one going bad as I had low b++ in one of my 7 inch sets because of a bad selenium rectifier. I replaced the 2 with 1n4007 diodes and cured the voltage problem. I had noticed one selenium was much hotter then the other so befor it shorted and and smelled up my house I changed them. Could be power supply caps too but I see your going over the whole chassis so I'm sure you will find the culprit. Does that set have an adjustable ring on the hv rectifier tube, if it has one that will affect the hv output.

Tim, this one has seleniums and I actually mentioned this to him in a post on another forum. I know he was intending to swap them out with diodes but don't know if he did yet. Personally, when I see seleniums soldered in place I get like the Lost In Space robot: "danger danger, Will Robinson!!"

This won't be difficult to scope out. Only real potential problem would be if a deflection plate in the CRT was bent or damaged and I think that's highly unlikely. Gotta be a vintage or capacitance issue, both easily remedied.

I'm happy he's got HV. This'll come together nicely with relatively short effort.

George

[Electronic M]

I run seleniums in my restored sets (radios more so than TVs). If B+ is good after a FULL recap, the seleniums run cool, the set has not been exposed to a corrosive/outdoor environment, and it is not a set I plan to use heavily then I just leave the seleniums in. Not all of them are ticking time bombs...

[Crist Rigott]

I replaced a bunch of caps and resistors today. I have an image now but it is very wavy. More caps tomorrow and I'll look at the selenium's too. BTW the B+ voltage rose from 228V to 251V. At least it's in the right direction.


https://youtu.be/kSXk_JTiJQQ

[Crist Rigott]

This reminds me that I need a TV pattern genterator or one of those DVD's/videos. I have a vhs and a DVD player. Do I DL a test pattern the make a DVD, then have hte DVD palyer paly into the VHS player which "talks" to the tv?

[reichsrundfu]

Thats improvement Crist, when you complete the caps definitely do the two selenium rectifiers. At the absolute least you'll know that you will have full voltage coming forward from the rectifiers and they are going to be stable and safe. Then address video & sweep issues as they may appear!

-George-

[Crist Rigott]

George,
Right!

[Crist Rigott]

I finished replacing the paper caps. All the E-Caps have been replaced. When a resistor and capacitor share the same point, the resistor got changed too.

B+ is still too low. Selenium's are next to get replaced.

Getting closer.

https://youtu.be/CzThLSIsM9Q

[reichsrundfu]

Well Damn! Thats looking pretty nice! Your vertical height is excessive but the nice part is that can be corrected by adjusting the vertical height pot on the back!!!!!!! :-)

Damn good work Crist! And that picture is looking pretty nice and sharp, and with good greyscale too!

-George-

[reichsrundfu]

BTW: I betcha you'll be amazed when you get full B+ on a nice new set of diodes!!!!!

-George-

[Crist Rigott]

Originally Posted by reichsrundfu

BTW: I betcha you'll be amazed when you get full B+ on a nice new set of diodes!!!!!

-George-

I replaced the selenium's tonight per your instructions. Work great except I need to go down to 20 Ohms to get 308 volts. Sams list the B+ at 310 volts. Still more issues and I'll keep replacing more resistors tomorrow.

I am keep a tally on each resistor as to what it checked when removed. There were quite a few that were out of tolerance, some were almost spot on, and several were low.

The picture tube isn't as bright as I though it should be. Can't see it with the lights on.