1971 Philco color Tube Hybrid

[Lain94]

Well, I am having a lot of luck this week. I added yet another tv to my collection this will be my second tv with vacuum tubes in it. This is a 1971 Ford Philco color hybrid tube/transistor tv. It has 18 tubes in it and 10 transistors in total. Looks to be a pretty low hour set, barely any cataracts on the screen. A bit dusty but not too bad. Cabinet had no scratches but damage on the lower right hand corner of the cabinet. I have no idea for sure how long it has been since this was powered on and used but I am guessing 20 years. I picked it up for free in the blistering 100 degree heat today in a house that was being cleaned out for sale by a family.

Basically this woman's grandparents never threw away anything, the house was built in 1925 and was NEVER remodeled after the 50s.

Anyways the chassis number is 20QT74. Model is G703OUYA I believe, not 100% sure about the model because the stamp of the model was blurry.

I have not bothered to attempt to turn it on at all yet, as it is highly likely capacitors are bad if I had to guess. I may open it up later tonight and take a look inside.

https://imgur.com/a/HeDCoxn

[Electronic M]

I've got a similar table model with cart and the, I guess optional, tuning eye tube tuning indicator. I don't run mine much because the flyback likes to run hot.

These have the same brown paper labels the old 30s Philco radios had.
If your CRT is original Philco then it will get RCA looking cataracts that somehow respond to the Zenith guitar string cataract removal procedure...One of only 3 RCA looking cataracts I've ever seen respond well to the guitar string method.

[Jeffhs]

The statement that this Philco TV belonged to someone who never threw out anything reminds me of my late grandmother (my father's mother). She never threw anything away either, if she could help it. She had a 1951 GE 16" TV and a 1948 Sears Silvertone radio-phono (not to mention other relics of the 1950s and earlier) for years, until she moved to our house (long story and OT) in 1972. The reason she kept all this antique stuff was because she lived through the Great Depression, during which, I am told (I'm 66 and hadn't been born yet at the time), people kept everything they could as long as the stuff worked or could be repaired. My grandmother finally replaced her GE 16" 1951 console with a color TV in, IIRC, 1969, but until then, as I said, she kept her GE set as long as it worked.

I had never seen anything like it before in my life. The VHF tuner's channel knob had the letters "UHF" printed on it between channels 5 and 6, and the tuner itself had two RF amplifier tubes, great for use in fringe areas miles away from the nearest TV station. This wouldn't have been necessary where my grandmother lived until 1972, as the area was suburban Cleveland which received all three [at that time] Cleveland television stations, and an outdoor antenna wasn't necessary either, at least in that area, as the set pulled in great pictures with just a pair of "Spico" rabbit ears.

The TV also had a focus control on the front panel, behind the trap door between the volume control and the channel selector, but I don't remember ever seeing that control being adjusted, even at the end, when the set was replaced.

I inherited that GE TV when my grandmother got her color set, but the GE set stayed in our basement for years (again, long story and OT). The set worked well for the next two years, until my dad and I moved (once again[!], long story), but before then, I remember sitting downstairs in our basement with the TV on, enjoying a program. This wouldn't have been anything to write home about, except when a commercial came on and I reached around behind the TV. I'll never forget it. I was greeted by a large spark near the junction of the power cord and the interlock plug; obviously, the insulation was crumbling at that spot (and likely elsewhere on the cord as well, as those old cords were insulated with material which eventually deteriorated).

BTW, today's AC line cords, for televisions and for everything else, thankfully, are now made of material which will not crumble under normal circumstances. To this day I am amazed the crumbling insulation on the interlock cord of my grandmother's TV did not cause a fire when the cord eventually put a dead short across the AC line. The only thing I remember seeing was a huge spark, but somehow the cord still worked after that.

I didn't take any chances, of course; I immediately replaced the crumbling old cord with a cheater cord, which allowed me to use the TV until I moved. The set was rather unceremoniously put out for the trash at that time, along with every other old TV I had except two; one was a color set which eventually quit in '73, the other was a Sharp 12-inch b&w portable, which also gave up at the same time.

An interesting side note: When my dad and I were getting our house ready for my grandmother to move into, we were throwing out old TVs from the basement right and left. I couldn't help wondering what our neighbors must have thought, seeing all those old televisions being carried out our front door; looking back on it, it wouldn't have surprised me if our neighbors thought we had been running a TV repair shop in the basement at the time.

[zeno]

The Philco hybrids were a very good set unlike the rest of the line
at the time. Awesom pix with an updated CRT. Reliable too !

73 Zeno
LFOD !

[Lain94]

Welp, an update on this tv, after going through the capacitors and inspecting the tv and getting it turned on. The 6KD6 Horizontal output in the tv started arcing like crazy within seconds of power being applied. I quickly turned the tv off. I am guessing that tube is bad. And of course naturally it is the most expensive to replace tube in the set I later discovered when searching ebay. Also the thermistor attached to the degaussing coil is burnt looking and had no continuity which explains why the degaussing coil was disconnected from the tv by someone at some point.

[Notimetolooz]

I think the CRT would be more expensive to replace.

[ARC Tech-109]

Give me an idea of what you think a good used 6KD6 is worth and if no one else steps up to the plate I will look at my bins. I'd much rather help out a fellow member than go for a profit. I'm also an Audiokarma subscriber so we can do the business thing there and stay with the rules.

[Lain94]

Originally Posted by ARC Tech-109

Give me an idea of what you think a good used 6KD6 is worth and if no one else steps up to the plate I will look at my bins. I'd much rather help out a fellow member than go for a profit. I'm also an Audiokarma subscriber so we can do the business thing there and stay with the rules.

Thanks for the offer! I actually went ahead and ordered and got a brand new NOS RCA 6KD6 tube on ebay for $35ish dollars including shipping. I replaced the old dodgy looking one in the tv and sure enough the new one works fine! Funny that I guessed the 6KD6 was bad even before I turned the tv on and was right just by visually looking at it. Anywho, now there is arcing in that metal box where the flyback is. Luckily flyback still looks fine but the arcing appeared to be happening where the HV rect. tube is hanging from upside down in its socket. So it may be a bad HV rect. tube now. I already ordered and got a replacement for it just in case so hopefully that is all it needs. I managed to get to the point where the CRT high pitch whine could be heard, CRT filament lit up but no light or picture on the tube, solid state sound was heard loud and clear. Then that was when HV rect. tube or something really close to it was arcing and I quickly turned off the tv.

It scared the heck out of me lol.

[ARC Tech-109]

The 3A3 has a habit of dropping the filament into the plate over time when they're running upside down, this will take out a flyback in short order.

[nasadowsk]

Originally Posted by ARC Tech-109

The 3A3 has a habit of dropping the filament into the plate over time when they're running upside down, this will take out a flyback in short order.

Wasn’t that the way most RCAs mounted it after the CTC-15?

[ARC Tech-109]

RCA & Magnavox were notorious for this, the 3A3 was a fast heating rectifier while the 3CU3 was a heater cathode. More than once I've dropped the heater in the 3A3 with the RCA flop top cage cover, not a problem if caught right away... wrecked a few flybacks and 6LQ6's this way

[Jeffhs]

Originally Posted by ARC Tech-109

RCA & Magnavox were notorious for this, the 3A3 was a fast heating rectifier while the 3CU3 was a heater cathode. More than once I've dropped the heater in the 3A3 with the RCA flop top cage cover, not a problem if caught right away... wrecked a few flybacks and 6LQ6's this way

What were Magnavox and RCA's design engineers thinking? Mounting the HV rectifier socket so that the tube would be hanging upside down is a one-way ticket to disaster in that the flyback, not to mention the horizontal output tube, will be destroyed if the 3A3 shorts for any reason. I don't know if this was eventually corrected; however, given the problems it can cause, I would hope it would have been, sooner rather than later. After all, it costs a lot less to replace a 3A3 or 3CU3 tube than to replace the flyback.

[jr_tech]

“What were Magnavox and RCA's design engineers thinking? ”

The datasheet for the 3A3 does indeed allow any mounting position for the tube:

https://frank.pocnet.net/sheets/049/3/3A3A.pdf

https://frank.pocnet.net/sheets/135/3/3A3C.pdf

jr

[Lain94]

The HV rectifier tube in the tv is a 3DC3. Not sure if it has the same issue with a filament falling out. After safely discharging the CRT and disconnecting the HV rect tube from its socket, I found out where the short was!

It appears that there was arcing from a bit of exposed copper wire leading to the tip of the HV rect tube. It seemed to perhaps be bypassing the corroded metal clip in the plastic nipple cap that goes over the tip of the tube.

Here are some photos.

https://imgur.com/a/wMMNkQ0

Any ideas or suggestions of how to handle this safely to stop the arcing?

[Electronic M]

Clean it with rubbing alcohol or goof off, file or scrape off any remaining carbonization of the material, apply some silicone over the arc point and let it cure.