Abandoned RCA B&W tube portable TV - can I resurrect it?
 

Life works in mysterious ways...as I'm wrapping up restoring the 1957-58 Zenith I've documented in another thread, I was preparing to get some other projects finished and just generally put a dent in my "to-do" list for the old TVs, radios, and computer stuff I have that needs fixing. However, I went to a family friend's farm to do the yearly pecan picking and ended up finding...more TVs, buried deep in a pile of trash.

I saw the back of one sticking out from the underbrush and after digging for a while, I ended up with a 15" black and white RCA portable set and a ~19" Sylvania solid state color set (with a necked CRT :tears:).

Do you guys think I can get the RCA to work? I took a peek inside and all the tubes are there, the CRT is intact, and the yoke doesn't look corroded. I think there's a good chance it just might fire up...the tuner might be hosed, though, it took a hard hit in that corner and everything is pretty smashed.

More to come very soon.

There's so much good stuff out for free or very little money. Freecycle or Craig's list, etc.
The RCA is in too rough of condition to even try to get working. Pull the tubes, knobs and maybe the CRT.

It depends what you're trying to achieve. If you just want to make it work for the fun of it, like those youtube resurrection videos, then there's not a lot to lose by playing with it. Maybe you'll have some fun, and sharpen your troubleshooting skills.

On the other hand, if you want a useful working TV which can be used for its original function reliably, I'd say this one is beyond any hope.

Me, I'd leave it be, maybe pull the horizontal output tube

Sad as it is to say , Ya can't save em all ....

Target practice perhaps ? :uzi:

I'm mostly doing this for the fun of it. I like fixing things and this helps me with learning how to troubleshoot and repair, plus one day I might decide to put it through a deep cleaning and keep it as a conversation piece.

Pulled the back off today and was able to figure out the CRT and chassis numbers via a fossilized piece of paper buried in some leaves. It's a KCS168XA chassis covered in Sams 1268-3, CRT is a 15VACP4. Hooked it to the Sencore CR70 and after a few minutes of letting it wake up, it actually tests good! Cutoff is excellent, we have a winner here...

I measured across the AC line, and it registered as a dead short, which I tracked down to a bad line filter cap. I've clipped it out for the time being, who needs noise filtering? :banana:

The next step is the initial powerup. I have good feelings about this one, but we shall see.

Ya never know, it might be repairable to some level of usefulness.

Nothing wrong with having one functional zombie TV that nobody expects to power on and work....they are good Halloween decorations since if someone smashes a pumpkin into it and crunches the thing you didn't loose anything of any monitary value.

Sets that have spent prolonged time in the rain can have frustrating and weird issues...If it gets to be a dog don't waste your life and switch it to parts set status.

I dunno-I talked to the other day a guy who is one of the "Deans" of R-390/R-390A repair/restoration, Rick Mish, & he gets R-3XXs in from all over & the way HE cleans 'em up is disassembles 'em, puts 'em in his basement sink, puts some Dawn or other degreaser on 'em, goes after 'em w/a scrub brush, rinses 'em good, either leaves 'em in the sun for a day or 3, & don't fool w/'em til until the 2-3 days are up. Of course, R-3XXs are stainless, brass, aluminum, just a few washers are steel that can rust. TVs, especially likely Sixties toob portables, were prolly NOT designed to be so vigorously cleaned like that..

... :banana:

The damn thing works! The first picture is seconds after I flipped the switch brute force style. Mostly full raster with static and sound! I cannot believe the cobweb infused tuner actually still works and accepts a signal, but I'm not complaining. The audio is also nearly inaudible since the speaker no longer has any usable cone to speak of, but I'll worry about that later.

I hosed down all the rear picture controls with WD-40 and got them all to free up, so I can crudely dial in the picture now. The second picture is the result after about a half hour of tinkering. Insufficient height on the bottom, poor linearity, and a "hum bar" slowly rolling up the screen causing a wavy picture, but the damn thing actually works! The vertical sync is also way off, the control is cranked all the way down, but the picture is still unstable - it unlocks, starts rolling, then "re-locks" again a few seconds later. This one has me stumped, but it seems to worsen the longer the set is on, so perhaps it's some component drifting as it heats up. I will need to track down the Sams manual before trying anything.

And some of you guys said it wasn't worth trying... :D

Every fault you describe can be linked to bad electrolytics.

That's good to hear. I suppose I can tack some new caps on the terminals of the old one if worst comes to worst, need to dig the can out to see what values it needs.

Nice Job, I hope you can find replacements for missing parts.

On a recycle pile I just found a 15" RCA from 1972 just like your, a remote control version no less, and promptly turned it over to TVTim after a very minor adjustment session and a 17BF11, which was responsible for the weak sound. Never found a remote unit for it.

I have found rusty Zeniths and Philcos in farm dumps that were tougher than the elements, they worked just like this RCA did.

Kewl !

Disconnect the old lytic when you replace it...If you leave it in circuit and it has appreciable leakage current (the most likely failure mode) it will continue to cause problems until electrically disconnected.

ditto:smoke:

Small update: sloppily recapped the set by soldering extension wires. Had to substitute a few strange values, for example, I put 560uF + 150uF caps in parallel to replace a 650uF section.

I've gotten mixed results. The linearity and height improved, but I am still getting a hum bar and the vertical sync is still unstable. However, I did notice something interesting...disconnecting the 150uF cap improves vertical hold stability, and it locks for longer periods of time. I have a feeling I'll need to actually order the correct value online...the vertical circuit is rather precise after all.

Just a small word of advice-Caps are usually cheap, you may wanna order 2 or 3 for each place you are gonna replace 'em... They CAN be bad from the factory, I've heard, you may be kinda like me, a "Fat-Fingered Freddie" & end up bollixing up a few.. And, even if you're lucky enuf to have an electronics parts wholeseller close by, guess which ones they'll be "Outta Stock" on... Murphy's Law of Ultimate Contrariness-the most rigid, & Immutable law there is.. Just sayin'...I'm kinda excited over this Bad Boi gettin' a new lease on Life, too...(Grin)

These were a TV every 8 year old wanted in thier room. We could pick them up, was the attraction. Do you need a sams on this little wonder? Its good to know where caps go incase you're not the first one in.

I had the folder out for S+Gs but ended up not need it to button up Tim's set.

PM me with your email address and Ill scan it.

OK on the temporary extensions, but did you totally disconnect the old caps?

+1

Make sure to disconnect the old caps.

Yeah, I'll probably order a few extra for the stock. Might even get 10 of each for that sweet, sweet price break... :D

There is actually an electronics store in my area, I buy my soldering gear from them as well as the occasional IC socket or switch or whatever I might need at the time when I don't want to wait a week for shipping. The only problem...their capacitor selection is pretty subpar, lots of Chinesium stuff I wouldn't trust to last very long. Such is life.

That would be great! Thanks so much. PM sent... :banana:

Yes, I removed the old can entirely. The stamped values were on the side of the can facing inwards, so I had to desolder absolutely everything to figure out what it was.

I've been doing some more work on this set, so here's the weekly update:

A huge thank you to user DavGoodlin who graciously e-mailed me a scan of the Sams folder, troubleshooting will be a million times easier now! :thmbsp:

I pulled the vertical tube as I needed to take some resistance measurements from the socket, so I threw it on the tester for fun. Both sections test good.

The resistance measurements yielded some strange results - pin 1 measured around 3.8K, when I was supposed to be reading 3.3K. Perusing the schematic revealed it led to a 3.3K resistor which then goes to ground, so I pulled that resistor and changed it. I now get the specified 3.3K resistance reading. I don't think it was a very crucial resistor in the circuit, but I had the replacement part on hand and decided I might as well change it while I'm working on the chassis.

Unfortunately, I seem to have somehow made things worse - after replacing that resistor, I can no longer get the vertical hold to lock AT ALL, and the horizontal hold control is extremely sensitive to the point where I can barely even get the picture to come through without turning the knob extremely slowly and meticulously. A bad solder joint has also apparently developed somewhere, as on the initial powerup, I no longer had a picture, but it came back after a hard KNOCK to the side of the high voltage cage. I will likely end up reflowing a good bit of the solder joints on the PCB just to make sure it's reliable in the future.

Pin 2 also reads high - 2.48 meg, when the Sams calls for 1.9. That pin leads to a "junction" of resistors and things such as the height control, so I will have to do some further investigating.

I think Electronic M correctly predicted I'd be chasing down some weird gremlins. At this point, though, I'm pretty sure my problem is just a metric ton of drifted carbon resistors, a product of the TV sitting outside for so long and soaking in the moisture. More updates as I continue to work on the set.

Paralleling AKA jumping caps is an acceptable trouble shooting technique.
Just remember to unhook the old one if you fix it.
Stuff from the 50's back I would not do it as a rule.
Hoz hold controls were always bad on some RCA's. We just changed them
since we could have them in a day. It may be a "tin whiskers" problem.
Just clean the crap out of it. The control could be causing the no
raster also.
Most sets with PCB's have the boards soldered to the steel chassis.
They complete grounds & often broke loose. Also if the set is dropped
the PCB will crack at those points.

73 Zeno:smoke:
LFOD !