RCA 630TS flyback, how is it mounted?

[Jonathan]

Ok, well, I replaced the resistor. I then turned it on without the HV rectifier in place, mistakenly forgetting to put it back. I hear a pop, I then immediately turned it off, then I smelled something like a resistor burning. I lifted the chassis up to see nothing burned underneath. So, I then put the rectifier in and still got no raster.

So then I got a green neon bulb and taped it onto a plastic multicolored retractable wand that screwed onto a flashlight. (My brother and I used to hit eachother with it when we were little I turned it on and it glowed green when I placed it by the socket/standoff of the HV rectifier, the cap on top of the rectifier, the cap on the top of the H output tube, and the 1st and 2nd winding connections that connects to the caps.

After leaving it on for a while and seeing the neon glow, I turned it off and touched the HV rectifier and it was cool, not hot like every other tube. It could be bad, or the resistors under the HV rectifier socket could be bad. I'm just not sure. I'm sure that since the neon glowed, it means that the H output and rest of the horizontal section might be good enough to produce a raster.

So then I realized I missed a connection on one of the terminal strips. Appartently I never checked it over as much as I could. So I fix that and try it out. The fuse lamp lights! I put everything together and still no raster. So I got a #44 lamp and connected it to the filament pins of the HV rectifier. I turned it on and it glowed too. I put the HV rectifier back in and still no raster, it never even got hot like the rest of the tubes did. I checked the resistance of the filament and I measure 1.6 ohms.

Could the 1M resistor that is in series with the high voltage DC be open? does it usually fail?

Thanks.

Jonathan

[Chad Hauris]

There have been cases of resistors that are in the HV output going bad, so if there is one it may be a suspect. The check for HV DC is to unplug the set after operating it and discharge the CRT anode to chassis ground...if you get a spark then you know the DC portion is working.

Does this set use an HV filter capacitor (round cylinder with screw terminals on each end, and connected to HV line)...it could possibly be bad. If the tube uses a graphite coating make sure the outer shell of the tube is grounded to the chassis.

Also don't connect the meter to the horiz output plate lead with the lead connected to the tube, only meter the lead with it disconnected...there can be up to 5KV AC pulses at the plate of the H.O. tube when the flyback system is operating which can destroy the meter. With the plate lead disconnected, you are only measuring the DC from the B+ supply.

[andy]

...

[Jonathan]

Ok, well, I checked underneath the HV rectifier socket. The 1M resistor measures to spec. I can't get a measurement of the 3.3 ohm resistor because it is in parallel with the filament winding of the flyback. I exposed one of the leads on the neon lamp and touched it to the cap of the HV rectifier and it did spark and the lamp did glow.

Underneath the HV rectifier socket, the one of the wires from the filament winding was touching that metal ring. I'm going to hot glue it in place where it won't touch anything.

This set does have the HV capacitor. It was held to the chassis by a spring and a tension ring (I think you'd call it a tension ring, the other RCA 630TS clone set had the lugs of capacitor threaded, I misplaced it and can't find it anymore) so I have it held in place with a bit of solder and a short lead that is soldered onto the chassis. I was told that this cap rarely fails, but I purchased a 470pF 15kV axial leaded capacitor just in case. Would this work if the original 500pF cap is bad?

What is the purpose of the metal ring, and what is the purpose of the HV rectifier filter?

For now I'll glue the wire out of the way and hope for the best.

Thanks.

Jonathan

[Jonathan]

Well, I glued the wire and put back the HV rectifier, powered it on, but still no raster, however, HV DC is finally working (I think). When I discharge the anode, I get a spark. It's not a big spark, but seems big enough to hurt. I suppose this means the flyback section is finally working. When I discharged it, I saw a spot on the CRT light up too. This a good sign?

I still get no raster though. So I guess I must turn my attention to the video section, yoke, and focus coil. I don't think this set has an ion trap, it does not say so in the photofact. The CRT is pushed all the way in, with the two "U" wires touching the CRT. The yoke and focus coil are securly in place. The anode connection is on the top. The CRT is held level with the holes in the yoke and focus coil with a cardboard box and a memo book, so as to not put any stress on the neck and have it implode and ruin a very desirable and rare CRT.

Since there is no raster, should I turn my attention to the video section? Should I test for any bad resistors and make sure there is enough B+? The sound section doesn't really work except the amplifier, so I get static and hum, but nothing like static you get when you tune a frequency that there is no station. With a satellite receiver connected to it, I should get sound on channel 3 if the sound section is working, but it isn't.

Right now, I'm concerned about the raster, then I'll work on the sound.

Thanks.

Jonathan

[andy]

...

[RetroHacker]

Originally Posted by wa2ise

Careful! A pencil has a conductive core, namely the black part that does the writing. It's graphite, similar to carbon comp resistors. Not good for use around kilovolt high voltages.

Good point... Anoter fine example of me just needing to shut up... You're right - I hadn't thought about that. I had always used a lamp taped to the barrel from a plastic BIC pen, I guess when I posted I thought that "pencil" would also work. But yes, graphite is conductive, and while I'd hope that the amount of graphite in a pencil should act as a large enough a resistor to protect one from getting zapped(much), it's much safer to just ignore the things that I post

I like to think that I know what I'm talking about, but I guess I don't think about as much as I think... I think then therefore... Oh the hell with it. I'll shut up now.

-Ian

[bgadow]

Hey, I'm a real scaredy cat...got a 3 foot long ceramic rod-I guess it was out of some bathroom fixture or something-& I use that for cases like this. Just tape the neon lamp to the end & go exploring, or go tapping or whatever needs doing. Actually, the last couple times I did the neon test I just took out the whole drawer of neon lamps (out of one of those clear plastic Akro-Mills cabinets) & hold it close. Get all kind of glowing, nice & safe.

As for the tv, I would definately settle the ion trap question first. I know they don't have to be very far out of adjustment at all to kill the raster. If no luck dive into the video circuit, sez I.

[Jonathan]

I think I am missing an ion trap. The CRT that my Air King A1000 has is a 10BP4 from RCA. I think the inside of the tube is a dark color; the same color as the outside graphite coating, and not the aliminized coating required to operate without an ion trap.

It's odd though, because Just like the Dewald BT100 I got from ebay(another 630TS clone set), it came with broken H output and damper tubes, as well as a flyback with the mounting clips broken off (but it tested good with a DMM for resistance on every winding, so it is good). It also came with a deflection yoke and focus coil, but no ion trap. I am not sure if the inside of ther CRT is aluminized, I doubt it though. Both these sets came in similar condition. Both have no ion trap (though the ion trap is not at all mentioned in the photofact of the Dewald BT100 or the Air King A1000), and both came with the HV sections taken apart in a similar manner, with the H output and damper tubes either missing or broken, both flyback mounting clips broken off, and both good flybacks. Both also use the pilot lamp fuse in the HV section as well.

Also, this set (the Air King A1000) has a electrodynamic speaker with field coil use as the speaker magnet. In the photofact, it has a seperate 1H 300mA choke mounted on the botton of the chassis. I honestly perfer this than the electrodnamic speaker, so I ordered a 1H 300mA choke from Hammond (Hammond part number 158T) and am awaiting an audio transformer so I can use a modern speaker. Wonder why this Air King set used an electrodynamic speaker?

Anyone familiar with these 630TS clone sets made by radio manufacturers? Air King and Dewald made only radios, and probably in the late 40s they used RCA's 630TS chassis and cabinet designs to get some of the TV market.

Thanks.

Jonathan

[Eric H]

The ion trap is mounted on the neck of the tube between the bakelite base and the yoke. It can be a small magnet held on with a spring or it might be an electromagnet, which is hard to miss because it's so large.

The 10BP4 requires a trap, the 10FP4 is aluminized and doesn't.

This picture from eBay is supposed to be a 10BP4 but I think it's an FP4, look closely and you can see the shiny silver coating inside the glass between the screen area and the black dag coating, you can also see the shiny stuff around the anode connector.

[Jonathan]

I GOT A RASTER!!!!!! After looking in the garage for the PM ion trap, I realized my Air King did infact come with one. I took it and put it between the base and focus coil, and moving it around I FINALLY got a raster. I moved it around until I got the brightest picture. I adjusted the vertical and horizontal controls to get a picture that filled the whole screen. The only thing I see on the screen is horizontal and vertical retrace lines and nothing really more. I'll probably need to go over the horizontal and verticle sections so I get a stablized picture. The correct picture should be snow, right? There are no VHF channels in my area, so I'll use a satellite receiver to test it on channel 3.

Are these symptoms I'm having any indication of one single problem or a ton of little ones. I'm a TV newbie so I'm not honestly sure.

Eric,

Yeah, I saw that on ebay, it probably is aluminized. This 10BP4 in the Air King is nice and bright, but I might bid if I can afford it.

Thanks.

Jonathan

[Jonathan]

Turns out the first video IF tube socket is bad. When I move it around I get audio and a raster with something on it. It's the 6AG5, the 1st video IF amp. What happens if it's removed? Will it give me a blank picture? In that case, the horizontal and vertical is still screwed up, as I can still see scanlines. Should I go ahead replacing the resistors more that 20% out of spec?

Thanks.

Jonathan

[Jonathan]

Eric H,

Upon looking at a color code for the "Micamold" caps, I saw a thread where you said they were crap. I'm glad you verified this for me. The chassis is full of them. I imagine the ones that will go bad are the ones with B+ or high voltage on them like the video coupling caps. John told me about these as well(Are you Johnnysan?). Upon checking resistors I'm replacing these "Micamold" guys.

Jonathan

[RetroHacker]

Yeah.. Hehe - those Micamold caps are just good ol' paper caps in sheep's clothing... er.. mica clothing. Actual mica capacitors are pretty reliable and don't normally need replacing unless they've actually failed. MicaMold caps are, despite the name, not mica. They're just paper caps in a misleading, molded casing.

Good luck with your recapping! Be sure to post some pictures of your progress too. We'd love to see how he's coming along!

-Ian

[Jonathan]

Well guys, last night I was just tired, and work on testing resistors until 3AM and went to bed. Today I replaced the 270pF micamold caps in the vertical section and a few others in that section. Only ones left I have to change are the 270pF micamolds in the video section and one in the audio section. There is also a 470pF micamold on the sync input terminal (What was this even used for anyway?), but I don't have a 470pF silver mica cap so it'll have to stay for now. I should be getting the 7 pin mini tube socket for the RF amp tube that I cracked, and hopefully get some more decent operation from everything.

I'm still wonderring about the scanlines on the screen. This is when there is no IF signal going into the video IF section since the RF amp tube socket is bad, all I see is verical and horizontal scanlines. I even see retrace lines too. I'm hoping after I finish recapping and testing more restistors that I'll get some progress.

RetroHacker,

Pictures will come very soon. Most free time I get I'm working on the TV. I'll take some pictures in the next few days.

Jonathan