...ok, that may be overly dramatic at this point. It hopefully may not be a tragedy just yet. :tears:

I had picked up a G2000 a couple of years ago that had never been owned. It is in virtually brand new condition, just a couple of blemishes on one of the corners of the white veneer which seems to be quite common. The remote had never been used and was still in the black velvet pouch. Really cool and the chassis is crisp and clean. The only flaw in the set was a vertical issue that the height was a bit mal-adjusted and when I opened it up to fill the screen, the vertical would not lock, telling me of course that there is something up in the vertical circuits.

Anyway, I had powered up the set some time ago and it has a gorgeous picture and everything, aside from the vertical issue works perfectly. That is until last night. :no:

I was fiddling around with one of the DTV converters (I had picked them up months ago but finally got around to trying it out) and was enjoying this gorgeous picture, far better than my 36" 2004 JVC D Series which has a great picture, after about an hour, I heard a couple of "tink" sounds.....kind of like the sound of a tube as it heats up. No bangs or pops, then the picture was gone. Sound, tuner, etc was working fine but no pic and I cannot detect the sound of any hv. But this is a bit different of a beast from the tube sets so I am a little out of my element here.

My biggest fear is that something when nuts with the quadrupler. I can't begin to imagine where to obtain one of these. That is what would be the potential tragedy. Ugh.

I know there are a few of you out there that are experienced with this chassis. I must admit, I am a little overwhelmed by this chassis and while it is still similar to previous CTC 16, 17, 21, etc chassis...it is still very different. There is a massive amount of components in it and wondered if any of you who have dealt with this chassis might have some ideas on where to begin.

Hopefully it is just something in the power supply, an electrolytic that failed but I thought I would glean some knowledge from those more experienced than I prior to digging into this set.

Thanks in advance!

Well, it is definite. NO HV.

I spent some time going over the chassis looking for signs of anything that had gotten hot. The 3 E-Cap cans were running cool. I checked the flyback to see if there was anything going on in there (signs it had gotten too hot, etc) and it looked good. As a matter of fact, this chassis has virtually had zero time on it. There is no dust/dirt, I mean none in the hv section or around the yoke. Just a light dust layer from sitting.

I did hear a little sizzle and smell a hot component in the hv area. Perhaps there is a bad cap on the underside of the chassis. I will have to pull it and have a look. There is an odd component just below the focus control that was a bit loose. It is a circular shaped component with two wires going into it. I disassembled the component and it seems to be a coil of some sort.
The windings wrap around a plastic piece and are covered by a cloth tape and this is sitting in a clamshell, ferrite core that appears to be more of a choke than anything but does get a little warm. A ceramic resistor at the flyback tuning coil does get customarily warm/hot so there is some power in there somewhere.

I know there were paper/wax caps in the hv section of my CTC-21 and CTC-38 chassis. Did RCA put those there in this chassis too? It would seem kind of odd since it is just chock full of orange drop type caps.

Tube chassis are so much easier to deal with. This is my only vintage solid state set and I think I will keep it that way.

Any thoughts as to the HV problem would be appreciated. I just hope to heck the quadrupler hasn't fried. Does anyone know of where to obtain a replacement?

Thanks

The quadrupler should be easy to check. Unsolder the lead from the quadrupler that connects to the flyback. Position the lead where it can't arc to anything. Turn the set on and hold a screwdriver close to the end of the loose wire. If you get an arc, you have HV coming out of the flyback and the problem most likely lies with the quadrupler. There may be an NTE or ECG equiv. to the original RCA quadrupler. Usually, when a tripler or quadrupler fails; it either arcs, burns, cracks open, shorts and trips the CB, or causes focus problems. It's rare for one to fail and kill the HV without causing some other action.

The problem is more likely to be in the horizontal output circuit. I'm sure this set uses SCR's in the horizontal output stage and I have seen these fail in the more common XL100 sets from the early '70's. I've also seen the horizontal oscillator circuit kill the HV. On the XL100's, that circuit is on a module. I think your set is non-modular. You'll probably need to get a Sam's Photofact (if there's one on that chassis) and check some voltages in the horizontal circuits. Trust me, these old TV's are a lot easier to fix with a schematic.

Thank you for the info.

I do have the schematic for the set. This one is just so different from what I am used to that I am not too sure of myself.

I am also going to ask a dumb question....what is an scr? Are these the round transistor like units mounted to large heat sinks?

You are correct, the set does not use modules with the exception of the boards in the tuner circuits.

The quadrupler....what I am assuming to be the quadrupler (a black, square box about 4x4 and 1.5-2" thick. Reminds me of an old ford computer module from the 70's appears to be pristine as does the rest of the set.

I am sure I should go ahead and replace the e-caps since they ARE 40 years old.

Frustrating, aside from the vertical issue, it was working so well.

I realize it is basically the same as my CTC-21 etc, but with tubes, things are much more easily laid out and seems easier to work on. Probably just a silly perception.

000

radiotvnut: I'm sure this set uses SCR's in the horizontal output stage and I have seen these fail in the more common XL100 sets from the early '70's.

Can anyone tell me what the SCR is? I am sure this sounds dumb but I am not familiar with this component acronym. It is a little embarrassing. I mean while I have restored radios and a b/w tv and have replaced components and the fly in my CTC-21 and a Sylviania color set (that was when I was about 20) set....there is a whole massive world of knowledge that I still have yet to understand.

Thanks for your patience everyone!

Silicon control rectifier.... Those RCA are notorious for having those fail, but usually it's because of an underlying problem like lack of horizontal drive pulse, etc.

Unfortunately, I have very, VERY limited experience on those early solid state RCAs. That's a CTC-47, which is similar to the CTC-40/44. Not having the schematic in front of me, I can't comment on it. But I'd start by tracing from the horizontal oscillator (see if it's running), then down the line to the horizontal output. If the output SCR is blown, and the horizontal drive pulse is OK, then it could either be a plain old blown SCR, or you could have a load on the high voltage (bad tripler (quadrupler in that set???), or a shorted flyback, etc.

DO save that set!!! It's rare, and you will eventually get it working again.

Charles

Thanks Charles for the information!

I have no intention of discarding the set. It is too rare for one and it is in such pristine condition to do anything but repair it.

I would imagine that after 40 years of sitting, something in there would not be happy about being run.

Ok, the SCR's are located on the schemo. There appear to be two of them. Is there a way of testing these to see if they are good? Where would I go to located such a component?

I did smell something get hot and a slight "sizzle" last night while investigating it. Looking for the smoking gun as it were. I suspect the hot component is on the underside of the chassis near the HO board.

This is an odd bird for me, component wise.

I do hope the quadrupler hasn't cooked. It doesn't show any signs of splitting or arcing or catastrophic failure.

It probably boils down to a dumb lytic that crapped.

It will live again.

Ok, I went to Moyers site and tried to locate the SCR from the part number listed on the schematic diagram. The Sams does not show an actual parts list so I can only go by what is on the schematic diagram.

For the SCR's it shows 3585-3 for SCR 102 and 3585-4 for SCR101. Moyers comes up with sever components for 3585 but one does show it as a diode. However it shows part number RCA 253585...but I don't think that is correct.

Any thought about where these can be obtained would be appreciated.

Also, with regards to testing these...when looking at the component from the undersided, the case shows to be the anode, left pin the cathode and right pin, the gate. Are these just basically diodes?

I may be jumping the gun but if these are failure prone, it should be good to have them on hand if I can find them.

000

Very helpful indeed.

After getting my ctc-21 back up and running, I think I am feeling froggy enough to dig into this one.

I will keep you all posted.

For the SCR's it shows 3585-3 for SCR 102 and 3585-4 for SCR101. Moyers comes up with sever components for 3585 but one does show it as a diode. However it shows part number RCA 253585...but I don't think that is correct.

Any thought about where these can be obtained would be appreciated.



Your SCRs have abbreviated "drawing numbers" on them. The full drawing numbers are 1473585-3 and 1473585-4, both Commutating SCRs. RCA part numbers are 130025 for the -3 and 131346 for the -4. RCA nomenclature is Thyristor, which is a term that also includes Triacs.

So if you decide you do need SCRs, the part numbers are 130025 and 131346.

Cheers,

Okay, I'm replying again. I have some abbreviated service notes for the CTC47 chassis - these might help in the future.

Stuff to look out for, not germane to your problem:

-Piecrust or "geartooth" effect in raster - R423, a 1K resistor on PW400 could be open.
- Distorted Video could be C354 changing value. It's a 20uF 15V electrolytic, RCA part number 121995, although any generic 20 or 22uF cap will suffice.
-Hum bars in the picture could be R106, a 47 ohm resistor in the degaussing circuit opening. RCA part number 132951 is the replacement.

As to your existing problem, I'll dig and see if I go back that far in my RCA service literature. More to come.

Cheers,

Findm-Keepm Okay, I'm replying again. I have some abbreviated service notes for the CTC47 chassis - these might help in the future.

Stuff to look out for, not germane to your problem:

-Piecrust or "geartooth" effect in raster - R423, a 1K resistor on PW400 could be open.
- Distorted Video could be C354 changing value. It's a 20uF 15V electrolytic, RCA part number 121995, although any generic 20 or 22uF cap will suffice.
-Hum bars in the picture could be R106, a 47 ohm resistor in the degaussing circuit opening. RCA part number 132951 is the replacement.

As to your existing problem, I'll dig and see if I go back that far in my RCA service literature. More to come.

Cheers,

Thank you very much for the info.

I pulled the chassis last night and started looking for the smoking gun. Even though I smelled something getting hot, there was no evidence of it. I did pull a big ol e-cap, 250 mfd @ 175 volts......it registered 290-295 on my cap tester. Not sure if this is a big deal or not. I checked AES and they don't have a cap of this size so I will have to make one. I have a pair of 100 uf and a 47 uf cap rated for 350 volts. Is my thinking correct that wired in parllel, this should replace this big paper cap?

My other issue is to figure out the part number for the flyback and quadrupler so I can get onto Moyers and locate the fly and the quadrupler......I still need to test for continuity on the fly to make sure it isn't shorted. I seem to remember someone talked about how to test a fly, but I can't seem to recall it.

Is there anyway to check the quadrupler to see if it is ok? There is just no smoking gun that I can see at this point. From the descriptions of quadrupler/tripler failure, that is pretty dramatic and obvious so I don't know if this unit can fail and not show outward signs.

Thanks for the help all!