Late 50s philco curb find

[Old1625]

FYI I had long ago in the past restored a Westinghouse 21" table model that had been in a flooded cellar for what may have been years. It was thick with mud all over the chassis. I hosed the darn thing out, left it in the sun to dry, and fired it up after re-inserting all of the tubes and applying tuner-lube to sockets and all of the controls. The set worked perfectly for two years before the selenium rectifiers let go, and stank us out.

But that was neglect. What you have there may have involved "tinker-bobs"--which can make for a troubleshooting nightmare.

[JGlenn]

I did a little searching and it was actually a primitive pay tv service in that started in the 50s and never really caught on. I guess there would be a box that got some signal over the air and then some aditional signals over a phone line to unscramble. kinda interesting.

[wa2ise]

Originally Posted by JGlenn

I did a little searching and it was actually a primitive pay tv service in that started in the 50s and never really caught on. I guess there would be a box that got some signal over the air

There were those supressed horizontal sync scrambled TV stations, usually up at the upper end of the UHF TV band. We had one in the NYC area on channel 68, here's the box you rented from the service


The missing horiz sync signal was added to the audio subcarrier, along with the soundtrack modulated as a double sideband suppressed AM carrier at around 31KHz (twice the horiz frequency), a lot like FM stereo is done where the soundtrack would be the L-R signal, and a "barker" (someone telling how great the movie service is) sound on the baseband mono audio, to be heard by people tuning the channel without the decoder on their TV sets. Then the box would add the missing horiz sync back to the video, and send that to the TV set. You'd see tons of pirate decoder boxes at swap meets and such, most not working all that well.

Building such a decoder box using tube technology would be rather expensive, similar to a TV set but without the CRT and deflection circuits. That's probably why it bombed, that much investment would have to be paid off in a couple of years and then getting movies that just finished their runs in movie houses but before they hit regular TV would be expensive too. "Wometco Home Theatre" lasted about 12 years before it folded.

[jr_tech]

Slightly different more primitive system which would not work for color:

"The Phonevision system was operational on station WHCT in Hartford, Connecticut for at least two years, ending in 1969. The station would run conventional (non-subscription) programming during the day as an "independent," and then switch to Phonevision encoded programming in the evening. The system operated by switching a delay line in and out of the video, which chopped the picture into slats (like looking through an open venetian blind). Half of the slats would be shifted to the right by a significant amount. Decoding reversed the process and slid the other slats over the same amount, realigning the picture. The video information was also reversed in phase, exchanging black and white. The audio was processed by "frequency inversion scrambling," shifting the audio spectrum up 2.625 kHz in frequency. This produced audio that sounded much like single sideband radio except that only high frequencies were present. Decoding of the audio was done by a dual-conversion processor. The audio was first shifted up 31.5 kHz, and then shifted down 34.125 kHz, producing a net "downshift" of 2.625 kHz. 31.5 was double the horizontal sweep frequency of 15.750 kHz, and 34.125 kHz was 13/6 ths of 15.750, giving a convenient frequency reference. The frequency tolerance was so tight that if encoded audio were recorded during a Phonevision broadcast, and then played back later into a homemade processor running on normal network programming, a slight frequency error could be detected in the restored audio. Also, when the station switched to local sync to run a local commercial, the frequency change could be heard. One of the major limitations of the Phonevision system was that due to the delay line being switched in and out, color could not be broadcast, as the 3.58 MHz phase lock necessary for NTSC color broadcasting could not be held. This limitation contributed to the demise of the system, along with the FCC authorization of subscription programming about 1969."

From:

http://en.wikipedia.org/wiki/Phonevision

[Charlie]

Oh well in that case, your Hi-Def Dish Network or Direct TV should hook right up with no problem at all!

[JGlenn]

I finally borrowed a variac and brought this up today. No bad suprises thankfully and it has a raster, the bottom 1/3 of the screen is lit up gray and the rest is black with gray horiz. lines running through it and everything is tilted about 30 degrees. Where do I go from here? I'm a bit nervous to be poking around back there now that its been powered up.

[Jeffhs]

Cleveland had a TV station that operated much like the Hartford station did. The Cleveland station started out in 1968 as WKBF-TV (Kaiser Broadcasting) on channel 61, and was a full-service independent station until it went off the air (financial difficulties) in 1975. This station was replaced in 1982 by WCLQ-TV, also channel 61. This station operated, as Hartford's WHCT did, as a standard television station during the day (receivable just as well as any other local channel in the area), with off-network reruns and movies. However, at 8 p. m. EST, WCLQ-TV switched from commercial to subscription TV, and was scrambled from then until the wee hours of the morning (or perhaps it ran subscription TV all night; I never stayed up late enough to find out). A special antenna (cut especially for channel 61) and a special decoder were required to receive the pay-TV service. The station eventually gave up on pay subscription TV, becoming, in the late '80s IIRC, WQHS-TV, a home-shopping channel. That station ran for some time as an HSN [Home Shopping Network] affiliate (I don't recall how long) before it dropped the network and replaced HSN with Spanish-language programming from Univision, which it has aired (and is still airing, digitally of course since 06.12.09), to this day.

BTW, I picked up a couple of old Zenith TVs years ago (I no longer have them) that had input sockets on the backs of the chassis for a Phonevision decoder. I never saw the Phonevision system in operation (maybe it wasn't available in my area at the time the service was launched, or at any time while it was operational), but I do think it must have been a forerunner of today's pay-cable TV systems, in that a special converter box was required to decode the signal so that it could be viewed, and of course there was the usual monthly fee for the service. I also remember reading an article in Popular Electronics or one of the electronics magazines of the '60s having to do with a Canadian pay-television service called Telemeter, IIRC, in the early 1960s, which was Canada's short-lived answer to Zenith's Phonevision. This service operated much like the American Phonevision system did; however, one difference between the two systems was that Telemeter required that the viewer insert a certain number of coins into the box to view a given movie (the prices of these movies were shown on a special preview channel, which was the default channel the box showed on the viewer's television if no movies were selected). The Canadian Telemeter service also had a feature that supposedly thwarted theft of coins from the converter's coin box. If the viewer initially decided to watch a movie on the service and started to put a coin in the slot, then decided seconds later (!) that he didn't want to see it after all, the box would shut off (likely requiring reactivation by a Telemeter representative) if the viewer tried to pull the coin out of the slot before it dropped into the coin box. If the viewer somehow got inside the Telemeter converter and tried to shake the coins out of the box, the coin box was arranged so that it would lock from the inside, thereby thwarting unauthorized access to and theft of the coins already in it.

[Phil Nelson]

Originally Posted by JGlenn

Where do I go from here?

If you haven't replaced capacitors yet, now's the time to start. Begin with the electrolytics in the power supply. This article has some basics of recapping.

http://antiqueradio.org/recap.htm

Take your time and check things off in the schematic. The article includes sources for getting schematics and a guide for reading them, if you need that.

It's encouraging that you have a raster of sorts. It means some key parts are working. Don't obsess over getting a perfect picture right away. That may be pretty impossible while your TV is still full of dozens of bad capacitors.

Phil Nelson

[zenith2134]

It can be a lot of fun to just grab the schematic and get er runnin again...but most importantly be safe around hv leads and stuff...

Very encouraging to see a raster at this stage, as Phil points out.

[jr_tech]

If re-caping the entire set seems like a huge project, you might consider just doing the vertical circuit first (likely not more than 6-10 caps) then bring the set up on the variac and see where to go from there. You may develop some "troubleshooting" skills, by observing the operation of various circuits.

For grins, last night I powered up (on a variac) an early 50s 16 inch Philco that had not been turned on in over 20 years. I appears to have a vertical sweep problem similar to the one you describe. I intend to replace about 8 caps in the vertical section first (assuming that tube substitution does not fix the problem) and see where that takes me. Since I do not intend for this set to be a "daily driver", I will replace enough parts to produce a stable picture, and not "shotgun" the entire set.

jr

[stromberg67]

I'm so happy to see that Philco saved from the junkyard. Very interesting chassis layout, and a great picture. Enjoy it !!
I cut my TV repair teeth on mostly Philco's, and have sort of affection for them. Maybe one day, I'll find another worthy tandem-chassis set to restore.
Kevin

[miniman82]

Originally Posted by jr_tech

For grins, last night I powered up (on a variac) an early 50s 16 inch Philco that had not been turned on in over 20 years.

You just reminded me: I think I'll power up my Philco 51T-1634.... Just for grins.

http://myweb.msoe.edu/williamstm/Philco_Tetris2.wmv

[Mick AV-8]

Hi Glenn,
Looks like you have a nice project. Take your time, be careful and ask questions. The people here helped me in many steps..and my first TV resto a 1953 B&W now works thanks to all here. You will enjoy the challenge and love watching the nostalgia on TV. Brings back time and memories.

[miniman82]

BTW, JR: if you intend to repair that Philco, do yourself a favor and replace every single cap in it. Even the Micamold caps aren't OK, some of them were PIO when I cracked them open!

[Tubejunke]

Seems like there has been a thead before where it was mentioned that there were two types of 'Micamold' caps. One type, if I remember correctly, was paper inside the dotted case, which would be basically a fake, and of course being a paper wound cap would be one to replace. The actual "Micamold" caps are supposedly more like ceramics, you can leave them alone in most cases. There is a visual way to tell the difference. I wish I could remember.......help!

Perhaps someone else who remembers this thread can make sure my version is correct, and we can refresh the subject for newer people.