RCA Victor portable TV from the 1950s
 

Hello everyone today I finally got the old TV I was talking about, it's a 1950s vintage RCA Victor 12" B & W portable TV that is in a metal and plastic cabinet with a handle on top and it's white colored.

Interesting thing is that it's got both VHF and UHF tuners on it and built in antennas.

Any information about the TV?

Pictures of the unit in question posted below.

Same set (17inch) in maroon:

http://www.tvhistory.tv/1959-RCA-170P063.jpg

jr

Cool.:thmbsp:

Cool, thanks for the link. So, mine doesn't power up when you turn on the power switch, and it does have all of its original RCA branded Tubes in it.

Also was this considered a high end set?

check filament of all the tubes.

This isn't a series string set, it has a power transformer in it, and I don't see any fuses in it.

The tube placement chart and chassis number is missing from the set so I don't know if I can find a service manual for this TV or not.

Here's some pictures of the inside of the TV.

Very nice! Looks like it'll clean up real well, should be a fun project. Sams index says 513-2.

I have the same set, 1959 I think, great performer when restored.

It has a fusible resistor I think, that will kill it if it's open.

OK so I think I found the fusible resistor yo were talking about, and it actually tested fine, it said it had continuity according to my continuity tester on my DMM.

But there was one part near it that I wasn't sure about what it was or what it was supposed to be and it appears to be damaged whatever the part is, and it looks to be part of the power supply.

see picture below.

Unfortunately I don't have Sam's Folders going that high, my Sam's Folders only go up to 469 and they aren't even a complete set of Sam's Folders going that high.

That looks like a Thermistor, I seem to recall replacing one in my set. If it is you could just jumper it and power it up with a variac or dim bulb tester.

Just found it, 1.7MB in PDF format, can you provide email address, I send it to you ASAP. see if you can use it.

You mean the mystery part?
If so what was the purpose of that thermistor in that spot, and how do I jump it?

My understanding is that thermistors are a sort of heat-responsive resistor. It starts out with high resistance to prevent current inrush on power up, and quickly drops to basically 0 as the set warms up. It's a protection thing, but you should be safe to eliminate it for now.

You could literally use alligator clips on either side or solder a wire to bypass it for the time being. I'd recommend replacing it if it's bad, though.

Feel free to correct me if I'm wrong. I'm not nearly as experienced as some people here.

A common repair mans trick was to just twist the leads together... replacement is better but not strictly necessary in most sets.

Ok, thanks, that might be why it's refusing to power up because that thermistor thingy is burned to a crisp and broken in half.

ok, I'll give it a shot. :thmbsp:

Good News, it was just a failed Thermistor, as soon as I bypassed it using the method Electronic M suggested, the TV powered up and the TV was working perfectly, no distortions in the screen or anything, nice full screened raster with snow and white noise to go with it, all while working with its original RCA branded tubes.

See Picture Below.

Here's some even better news, I think this TV is a low hours set because after I left the tv sit powered on for 5 minutes the picture became nice and bright!

I have a feeling that what happened with this TV is that it got struck by lightning at some point in time and the lightning strike fried the thermistor which saved everything else in the TV thankfully and so the owners of the TV just put it away and bought a new TV to replace it because they thought the TV was toast and didn't want to pay to have a repairman out to look at the set.

unfortunately the brightness control don't work right and on the ride home the the vertical hold knob broke.

CRT probably woke up from sleeping sickness.

Those thermistors were designed to get hot and often would unsolder at the point the leads joined the resistive puck... Sometimes the pucks would crack too. These were high failure parts in color TVs (which was the main application for them).

Check the brightness pot and if it is good change any caps in it's circuit that might be leaky and dragging it's output.

Ok, thanks, I'll check into it.

Although this set has mostly Mylar caps in it except for about 4 paper caps that I saw on the back of the set so it seems that there shouldn't be too many caps needing changed in this set.

The early mylars are not completely above failure, but are very low failure....I've found 2-3 genuine bad ones out of many dozzens encountered.

By the looks of how nice that sets plastic is I'll agree it may have been a closet queen most it's life.
Post a couple close up's of the broken knob and possibly someone will have one in their stash.

Here's a few photos of the broken knob on my TV.

IIRC, the set is considered to be a 1961 model.
RCA made about three years of that model. The 1959 model used a 5U4 rectifier, where the newer ones used the voltage doubler circuit.
A member of my family had a 1960 model that was the TOTL. It had a two-tone charcoal and white cabinet with all chromed metal knobs and a better looking front bezel.
The one you show is a lower priced version of basically the same set.
The TOTL 1961 models had a new-vistor tuner.

Yes, and apparently it also came with a remote in the Top of the line models...:scratch2:

My tv seems to have developed a vertical problem where the top of the screen isn't going all the way up to the top and it bounces around, and the vertical output/oscillator tube is still good yet, any ideas as to what could be causing the unstable vertical?

One theory I have is that the vertical section has about 3 paper caps in it which may have become leaky, but not sure if that's the problem or not.

OK so I was looking in the Sam's Photofact for this TV and found that the specs given in the manual for the thermistor for this TV is 120 Ohms Cold, with that in mind what kind of thermistor should I get?

I know there are two different types of thermistors, ones start off high resistance when Cold then as they warm up they kick in at zero ohms and then there's ones that start off at zero ohms cold and as they warm up they get higher in resistance.

I'm assuming I'm going to need one that starts off high resistance cold and then goes to zero when its warm, if so would any of the thermistors in the Mouser link below work in this application?

https://www.mouser.com/Circuit-Prote...z0x6xbZ1z0z5h6

Thanks for your help!

Yes, but choose one based on amperage. See what your TV draws for nominal running current as the resistance of the thermister will be based on what percentage of its rated current is being used.

If the TV normally draws an amp, pick a 2A thermister. Running at half the current, the resistance will be an ohm or two.

If you pick one too high in current rating, the thermister will have a higher run resistance which may or may not be an issue.

Also, if it's not mounted in the board, make sure to get one with leads! :)

John

I did a '56 RCA KCS 94 a month or so ago in this thread

I used this to replace my crispy inrush limiter thermistor:

https://www.mouser.com/ProductDetail...3uJp0Cqw%3D%3D

Works great!

Well I got it going except for the yoke positioning, I forgot to mark the yoke position when I removed the picture tube from the chassis so I could get to the vertical section to replace some old paper caps on the board that were causing the vertical to be unstable.

So now I have to blindly guess which way the yoke needs to go on so that I can get the picture to be right side up instread of being sideways.

Just install the yoke dirty side up...even if you cleaned it there are probably still some nooks and crannies with dust to indicate which end was up...

Well the way the yoke is wired in there's only one direction it can go but for some reason I can't seem to get the yoke oriented correctly so that the picture isn't slightly tilted to right or left or completely sideways.

If you are getting close, you should be able to zero in with tiny adjustments to the rotation. (?)

Well I think I got the rotation fairly close to where it should be for right now.

But the TV is still doing some funky stuff, I have a video I have made of what the TV is doing that I will post below.

https://youtu.be/GKZbM7sdD4s

The TV is flickering, bouncing up and down and the screen's height is still not right (and its not letterboxing either) and the top of the screen is stretched much more compared too the bottom of the screen.

Any ideas as to what could be wrong with the set?

Yup...put some kitchen grade rubber gloves on and rotate the yoke with the set on while watching the screen. That is the only way to get it exact without taking forever.

If you know where on the yoke it is and isn't safe to touch and have as much brass as I do you could do it bare handed...granted the yoke can bite more painfully than HV (ask me how I know) so gloves are the safer way to do it.

OK So I think I may need to either source a new picture tube for this TV or else get ahold of some paint to repaint the back of my picture tube because my picture tube's 'dag coating has failed on me, several large chunks of the 'dag coating on the back of my 17DSP4 has flaked off which is causing my picture tube's flickering problem you see in the video I uploaded onto youtube and posted a link to on here.

So does anyone on here have a 17DSP4 picture tube they would be willing to part with? I would hate to have to ditch the original picture tube from this TV as it still performs nicely (it still has lots of life in it and is still nice and bright).

But the only way I could save this picture tube is if I could source some of that paint some of you guys on here use to repaint the back of these picture tubes with, but I don't know what its called or where to get it from, or how to go about applying it without messing it up, as I've never used it before.

Help!

I use slip plate to replace failed aquadag. https://www.amazon.com/Slip-Plate-Pl.../dp/B005ESITFQ

One can will do several 20" CRTs. The process to recoat is fairly straightforward: remove neck hardware from CRT and remove CRT from set, place CRT face down on soft material to prevent screen scratches, scrape loose dag off with stiff brush, clean bell with glass cleaner and repeat brush down, mask off screen and ~2" perimeter around HV connection with blue masking tape and paper, also mask off 2" perimeter around neck on bell of CRT (can throw plastic bag over neck and tape that down), then coat the bell with slip plate the way you would if you were spray painting it, let dry and reinstall into TV.

The original dag had perimeter boundaries...if enough of it is intact for you to accurately discern those boundaries use the original boundaries as the masking edges instead of my crude mask here and 2" this and that advice above...the dag should all be connected to it's self there should not be any islands of dag.


Do not replace your CRT over dag flaking... suitable dag replacement material is being made, but new CRTs compatible with sets of that era are not made and will not be made again.

OK, thanks. And yes there is plenty of the original dag coating left on the tube but they aren't connected to each other on the bottom which was where the biggest section of the dag coating had flaked off.

the top part had some flake off but not enough that would cause the top part to not be connected from one side to the other.

I got some of that slip plate coating ordered now, and it should be here by next week sometime hopefully.

So if about 75% of the original dag coating on the back of the picture tube is still intact undisturbed can I just coat the areas that were disturbed and that's it?

I'm asking because the way this TV's dag coating had failed was that only a small section about the size of a quarter had flaked off on the top side of the picture tube and the rest of it around it is untouched and shows no signs of flaking anytime soon, and the bottom side of the picture tube had a section of dag that failed that was about the size of my fist but the rest of the dag coating around that area is untouched as well and also shows no sign of flaking off anytime soon.

It was just those two aforementioned sections that decided to fail, the rest of the dag coating looks like new yet and is untouched and doesn't show any signs of flaking or getting ready to flake.

Thanks.