That one is definitely not for the small Motorolas.

https://frank.pocnet.net/sheets/137/4/40A1.pdf

OK, so THIS is what it's used for, :D
no idea where I found it!

I think it was used in dual power portable radios.

Thanks everyone for their input and especially to Bob and others who took the time to post design drawings and their advice. I think I will give Bob's diode and thermistor design a try first as I have several of the CL-90s and a pack of 1N5408 diodes. I actually lost sleep last night over my clumsiness in losing the very rare 303 glass ballast in my mini-Hindenburg event. Oh the Humanity! Klutz!

Just bought this 459 replacement on eBay. Looks like this company (JFD) did make a replacement for the 303 at one time. I'll either modify it or canabalize it to make Bob's replacement

If it's still good I'd leave it alone and add the CL-90 under chassis.

Plug it in try it who knows it may work most of those ballast rust up inside and they are just to old and don’t work.

Can't hurt right? I've done plenty to F&$# up this TV. What more could I possibly do to hurt it?

Says it's NOS so who knows. In the original box and packaging.

Is that the ballast for your set because there are 2 different ones.

It isn't, but should work with a minor modification. The '303 has an extra element, but I'm pretty sure the TS-4H doesn't use it.

He will need to move the ac line from pin 5 to pin 6

That’s what I will do.

I noticed when fooling with series string electrostat TVs that the heater would flash on turn on, glow bright, and then subside.
I thought it was due to them not being controlled warm-up heaters in these jugs, including the Pilot 3KP4.
Do I recall correctly?

I believe that's due to the inrush of current. I've always brought this TV and my Pilot up on a Variac.

Yes, it is due to the inrush of current when the filaments are cold. Using controlled warm up version (typically ending with 'A') does not eliminate the inrush current. It simply means it is well defined. Typically taking around 11 seconds for the filaments to warm up.

The series string doubler electrostat should have had a heater transformer on the jug to extend its service life.
Do any restorers do this for working display sets?

Some, though there's a better option. TVS (transient voltage suppressor) diodes (8.2V IIRC) in parallel with the heater will clip the peaks off the AC voltage clamping true AC RMS voltage at 6.3V. I'm planning on installing them in all my series sets next time I can place a mouser order.
The person that came up with this has a great scientific thread explaining how they work/how he came up with it over on ARF.

I'm building Bob's design. Waiting for the resistors. I think all I need to do is move the AC line from pin 6 to pin 5. I have 10 of the "Littlefuse" in the appropriate size for this TV. Bob's design incorporates a CL-90. Will that be enough to protect the TV from the surge?

CL-90 yup it will.

I built Bob's design for the replacement ballast but the CL-90 hasn't arrived yet so I bypassed it with a jumper and brought the TV up slowly. I'll solder it in once it comes. The image on the picture of the screen is not what it looks like. The bright area in the picture is spread out in a 3-4 configuration across the entire screen face. There's no video signal through the IF as before but there's audio.

My next question is does the electrostatic tube and focus in any way affect the installing of jacks for composite video? I'm not giving up on solving the IF issue but I'd like to know if that's an option.

The thing that makes adding composite video dangerous is if you forget to plug the TV into a power isolation transformer your signal source device will be destroyed...

Hi,
I follow your poor story since a while.:tears:
Do you have any signal tracer?
They make it easy to find trouble sections in radios.
Try one (see safety instructions when working on life chassis) to check the video amp
and IF-section.
Do you have a clean sound from a "TV station", means a DVD or VCR?

Regards,
TV-collector:stupid:

Back to this PIA TV inspired by Bob and his recent "Green CRT" video. I noticed the Sams and the Motorola service differ as to the direction of the 1N34 diode in the video detector. The service data has my chassis, VT-71H in it and the diode direction is the opposite configuration from how I installed it. I switched it around and it made no difference. I tried a different JP4 CRT to see if maybe there is a cathode issue with what I've been using and the "image", a full screen and bright raster with no video information getting to it, is the same. The sound coming off pin 6 of the video amp 6AU6 is clear and buzz free with plenty of volume. There's a new 0.047 uf cap replacement for the 0.05uf C-72. I've checked the 2 coils between the video signal off the plate and the CRT and their continuity and they are fine. Just for grins, I replaced them one at a time with the same coils off a parts chassis that tested fine with no change. Scope is down right now so I can't check signals but if I have audio getting through the detector, everything before it should be fine as far as the video signal correct? The only thing I have not confirmed are working are the 8 and 15 pf caps in the detector but they're the type that are supposed to never go bad. I am at a complete loss with this missing video signal. It's a real mystery. When I get my new, USB oscilloscope, I'll be able to do more accurate tests but until then, I'm totally stumped.

One bad but real possibility is that given the CRT is cathode fed it's video if a heater cathode short occurs it'll swamp out the video.

I've swapped out the 7JP4 with another good one I have and the picture is the same.

What about the crt plug bad connection at the cathode wire within the plug itself.

I have continuity all the way from the output side of the 0.05uf cap (C72 in the Sams) to the tabs in the CRT socket #2

I also replaced C31, the 0.1uf cap that feeds pin 1 of the video amp with a tested new cap and I re-flowed the solder connections at all points.

Well you could take the schematic and start at the video amp and work back from there with double checking all connections and components I’m sure you will come up with something we all make mistakes I have been in the same situation as you are with this set. It’s time consuming but it will be worth it especially if you have sound all that’s left is the video. Even one leg of a resistor placed in the wrong spot can be a headache it’s happened to me and all of us with these sets.

OK but I'm confused. All of the information from the RF/IF comes out of the detector at one point. According to another expert in this thread, if I have sound, I should have video. The signal for both audio and video go into the video amp through pin 1. Video comes out of a grid at pin 5 and audio comes out from a grid on pin 6. Audio information then feeds into the limiter, ratio detector, audio amp etc... Video goes to the CRT cathode through a 0.05uf cap that has been replaced with a new 0.047 uf cap. I've only been looking at the video route after pin 5. Should I still go looking backwards?

Well yes it’s said that video rides along audio so you can still go backwards but at this point there could be a problem with the alignment coils and still have sound but no audio. Try different channels 3 or 2 or maybe 6 I had one of these sets that had sound but no video blank screen and it was a think ts 4h with the adjusting coils in front so I concentrated on channel 3 and eventually got video. Remember you probably don’t know the history of the set who know who was in it or what may be bad in the IF section.

OK thanks. Expecting a decent oscilloscope to arrive tomorrow and I also purchased a good 100X probe. I'm tired of trying to make this 45 year old analog Textronix work for me.

Have you gone through the Sams resistance chart for the CRT and 6AU6 video amp?

CRT and Video amp resistances are fine but pins 5 and 6 on the 3rd IF amp should be 1.2K and they are at <300 ohms. Both feed into the detector. The rest of the IF strip is fine. I have a parts chassis. I'm wondering if I should just swap out the detector.

No, if you have sound but absolutely no vide, I seriously doubt it's the detector. A scope should give you the answer in a few minutes. Start at the detector and go through each stage to the CRT. At some point the signal will disappear and that will be the problem point. I suspect either something is open or shorted.

Got it. I received my usb/laptop oscilloscope this evening and I’ll trace it out tomorrow night. Thanks Bob

Morning Bob...do you mean move forward in the circuit between the detector and the CRT or check the entire RF/IF string? Timmy has commented it's possible to have sound but no video due to problems prior to the detector but others have commented if there's sound, your video information is getting lost somewhere between the detector and the CRT cathode. There's not much between the detector and the CRT...a couple of coils and capacitors and all have tested good. I have a resistance on the video amp pin 5 that's spot on by the Sams. I've checked physical wiring continuity from the 0.05uf cap to the halfway plugged in CRT pin 2 and that's all there as is continuity through the 2 small coils after the detector. I've tried a different 7JP4 and have the same raster/no video result. Totally stumped but I will look for the actual signal with a scope next.

Between the detector and the CRT.
Check the signal at the grid of the video amp.
Check the signal at the plate of the video amp.
Check the signal at the cathode of the CRT.

Note that the sound is picked off the screen of the 6AU6 video amp while the video comes off the plate. So I'm thinking it's possible that circuit is screwed up in some way that allows the signal off the screen to be OK, but not from the plate.

Understood. Thank you very much!

Scope Pics
 

Keeping in mind, I just got this thing and my skills with it are very, VERY limited, I took pictures of the waveforms of the signals going into the video amp pin1, and out the video amp pin 5. The scope has an auto trigger and an auto adjustment feature that creates the best display parameters. First in pin 1 input from the detector. The second is pin 5 video output. Am I doing this trace correct so far? I've never looked at a video signal on an oscilloscope before. I'm feeding an RF modulated video into it and I have sound but no image information on the CRT...just a raster.