the IF is an intermediate freqency signal 44mhz. All the tuner does is takes the entire old TV broadcast band and selects a channel within that band and converts it to a single freqency, allowing for a better amp (only has to deal with one freq) to work. From there the AM modulated video signal is detected by a diode and the result is the composite signal. this is the same signal you get from the yellow rca lead on the DVD or converter box. the only difference will prob be the amplitude which is prob greater from the IF amp/detector diode vs. the DVD video out.

Ahhhh. For giggles I fired the set up and connected the tuner-out RCA line to the DVD player. No dice. I can't wait for my subber to get here.

I also thought it was rather convenient that the old man restored the tamper-proof metal thing that retains the cord in the set's particleboard back cover. It was loose when I brought it in and I mentioned offhand when I went to see it running with the subber that I could handle the convergence myself when he was backing away saying "nooo noo it's got plastic knobs and those things can break."

I'm a little annoyed I let the set sit with him so long. he apparently has moved on to bigger and better things as the shop is FILLED with flatscreens. He probably makes a killing replacing inverters, ccfl backlights etc. I feel a little cheated and let down that having all the old remnants of a 50s TV shop like carts that say "It Pays to Say RCA," a forgotten tube caddy just sitting there and a large file cabinet labeled SAMS PHOTOFACT, none of the original talent or expertise would be around to consult.

fujifrontier --->"How does it differ from the composite connection output by, let's say, a DVD player? "

The IF out is greatly different from Composite video. The tuner takes the carier radio frequency that has been amplitude modualted by the video signal, and frequency modulated by the sound at the transmiter, and filters out all but the carier frequency of the channel of your choice then mixes the signal with an oscilator whose frequency when subtracted from the frequency of the transmitter is is the IF frequency (there is also some amplification that happens in most tuners). To sum it up the tuner takes a station and lowers it's carier frequency to the fixed frequency of the IFs.

The signal then goes down the RCA cord to the IF amps which greatly amplify the fixed IF frequency that the tuner puts out(here the IF is still modualted in the same way as the transmitter signal at this point).

Then after passing through all the video IF amps the signal(containing both modulated audio and modualted video) is sent to the video detector. The video detector DEmodulates the video part of the IF and outputs composite video (but in most sets this signal also contains modulated sound that is split off and sent to the sound IF at this point) the remaining audio carier is filtered out here and the cleaned composite video is sent off to be split into Synch, color video, and monochrome video which after being processed by their respective circuits form the image you see on the screen.

You would see nothing resembling a picture if you connected that RCA IF cable to your DVD players composite out. So don't try it.


If any of this is confusing I can clarify (I could also deccribe the video circuits after the detector if your curious). The tuner IF and detector of a TV are a specalized type of "superhetrodyne reciever" circuit (google what is in the "" to learn more) with the tuner doing the job of all stages between the antenna and the IF(IF is short for intermediate frequency by the way).

Hope you found this enlightening.

again, if you want you can connect the composite video out to the test point I mentioned before, the inner part of the cable there, the outer part to the chassis ground. Its the stake that is at 4 o clock from the top of the cathode follower tube I mentioned before. It may work, will depend on the PP requirements of that tube. If you have a sams it shows you the test point. this will only give you video, for audio you would need to connect the audio out to the volume pot.

before connecting anything its best to test with a multimeter to test for DC potential.

there is another tuner repair guy in texas. his name is Louis Stangle from Quality Tuner repair services in Longview texas his phone is 877 753-3204 or 903 753-3204. I have use him in the past. request to talk to him Personally.
quality work!

is there a phone number for United tuner service?

I used Louis a couple years ago, nice work. But I was thinking that somebody tried calling him in the past year and his number was disconnected? When I had talked with him it sounded like he was running out of work.

Fuji: The front of the set say SS Color because approximately a third of your set uses transistors. You have four transistors in the tuner and six more on the chassis operating the video IF strip, video amp, and two for AGC. The rest of the set (color, deflection, sound) runs on tubes. I guess they thought they had enough transistors in there to say it was Solid State Color (even though the actual color circuits are tubes).

That's also part of why they call it a Cool Chassis... far less tubes in there, so not as much heat being produced.

Looking at your tuner photos, it's rather odd to think that the tuner from your color roundie set says "made in taiwan"

Haha that sure was a derp moment for me. SS= solid state. I'm a whiz when it comes to computers but this kinda thing throws me for a loop.

That is kind of odd to see Made In Taiwan on the tuner in any roundie. I do know for a fact that Philco-Ford had Taiwanese-built sets in the 70s..and maybe earlier .My 1973 19" b/w Philco Ford was made in Taiwan and is a hybrid chassis. Quality set, regardless of where it was made.

That may just be the UHF tuner that is made in Taiwan. I am also very surprised to see it. I didn't know of anything made in Taiwan and sold in the USA before about 1973, and this set is late 60s to maybe 1970, right?

He mentioned that the Philco tubes in there were date coded 1967, and, that model is listed in Sams 885... also 1967. My Philco roundie is from 68 or 69... cant remember which just now, but I will be interested to see if the tuner in mine is marked Taiwan.

I wouldn't suspect anything else in there being from Taiwan, but then ya never know! :dunno:

when my dad purchased our philco roundie it was 12/1966.the philco ford line had just been delivered the day before.spanky mcfarlane was in the store to promote.i have to say,the picture was outstanding.it was the brightest and sharpest in the store.of course,sun didnt sell a top of the line set such as zenith and rca.they did stock a few lower level,base models but their flagship was sylvania a few years later.our set also had tuner issues at the end of our ownership causing my dad to purchase a d-16 slide control sylvania.that set is still in operation at my brothers house.tuner was rebuilt by united tuner in the late 80s and a tripler was replaced.crt is still bright and sharp.now that was a set!

ok.

So, my tuner subber came in the mail. Hooked it up, and aside from some moderate dot crawl, bad colour, and misconvergence, the thing worked and showed a picture which looked A-OK from across the room but terrible sitting about a couple feet away. It had that... I don't know what to call it, but you can see the coloured lines atop the "good"pics. I was going to connect the LD player and use the A Studio Standard disc to do convergence adjustment, but got called away... I didn't want the set to burn the place down so I shut it off and came back about 45mins to an hour later. (MAC/MAC4.jpg)

Fired it up again when I got home and it started being a hateful bastard. (Rest of the pics.) To get it to show a picture I had to leave the 40mhz cable just barely hanging on to the tuner subber, all the way in and it would make a high pitched sound and the picture would act as if it were being fed a super strong signal (even with gain control at probably 5-10%).

The convergence pattern was bleedy and shaky, like a high frequency jello shaking; when a blocky checkerboard was on the screen it did a "flag" moving and shaking on the right side.

I don't know what could have changed in 45mins-1hr!

I can tell that it would have an absolutely GLORIOUS picture if it would behave, so I'm not keen to getting rid of it, but.... SIGH. With the tuner out of the loop I know that it's something else now that's either changing values or just too old to hold its water. Probably a recap?? Also... anyone familiar with the convergence procedure, LOL?

I've seen a few sets from the late 60s with imported tuners, Taiwan and maybe Hong Kong. Philco and Zenith seemed to be some of the pioneers in that.

The Philco-Ford rectangular console I used to have had that 'SS' emblem. I kick myself on a regular basis for getting rid of that one; at the time, before I had learned much about working on sets, that was probably the best working color TV I had owned. Traded it for a Truetone T-O clone and $15!

check your PM for instructions :)

looks like macro vision lines on the top, try a diff video source like that from a DTV converter box.

Yeah Dave I was thinking the same. Fuji, if you have any disc that do not have copy protection (like cheap movies and sometime old TV shows on DVD), try them. The copy protection on most discs will produce those lines.

Sometimes, you can adjust them out by adjusting the verticle hold just slightly, but if you adjust it too far then the hold lets go. Just play with the control and you'll see what i am talking about.

Since you have a Laser Disc player, that will work fine too. Laser discs and players do not have any kind of copy protection. However, on second thought, they do have frame numbers or running time encoded into the vertical interval, so that could show up on older sets maybe.

Macgyver? That used to be my favorite show to watch when I was a kid.
I think if it were me I'd bypass the tuner/IF entirely and go for a direct video/audio input.
I'm going to do this on a Curtis Mathes tube type console. Since analog RF signals aren't used anymore I'd rather not have to RF-modulate a video signal from a DTV receiver and go through oxidized old tuner connections and all those unnecessary IF stages. I will need to build pre-amplifiers for both the video and audio though.