TV149 question

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

This set has a 1 1/2" X 7/16" domino style capacitor in the RF tuning cage heating up and turning frosty white. According to Sams #56-#22 TV149 folder it's called out as a C92 (page 6). I cannot find it in the capacitor list or the schematic! The sams picture shows it as a round style cap but my set has the domino. I need to relace it but don't know what value to use.

Any help would be appreciated.
Thanks Mike

ff4312 · Member Joined: 09 Jul 2008 Posts: 190 Location: Florida

Is that the one on the terminal strip on the picture tube side of the tuner?
-Shane-

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

Yes that's the one. I'm in the process of recapping and noticed it was getting hot and burning the cap covering a frosty looking white in the center of it.

ff4312 · Member Joined: 09 Jul 2008 Posts: 190 Location: Florida

Let me pull my chassis and get back to you. I can't find it in the SAMS either.
-Shane-

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

One end of the cap leads to V1 pin #3 so I assume it is a filament cap. Disconnected it shows 92 ohms resistance. I sure don't want you to remove a chassis just for this. Mabey this info will save you the trouble. If i'm reading the schematic correctly it shows this as a C14 but it aslo shows it going to ground. In my set the other lead of this cap goes to a wire wound resistor in the tuning cage.

Thanks Mike

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

Correction: Both terminals on the strip that the cap connects to shows ground. C14 in sams shows a small dog bone looking cap so its not that one. It's probably in my face on the schematic but can't figure out which one it is.

antiqueradiobuff · Posted: Nov Wed 04, 2009 7:30 pm

The dog Bone is a wire wound resistor I have seen many in radios I beleive this to be true just double check the schamitic n the parts list there ya will find all the necessary info needed Very Happy

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Bill Thomas · Posted: Nov Wed 04, 2009 7:55 pm

I'm not so sure, William. "Dog bone" ceramic capacitors were commonplace in the 40's and 50's.

If it is dark brown, though, it certainly *could* be a resistor. Depends upon the size of it. If it's less than an inch long, it's *probably* a ceramic capacitor.

Bill

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

It's very small, a little less than a half inch.

Mr. Detrola · Posted: Nov Wed 04, 2009 8:58 pm

A picture is worth 1000 words......in this case someone may be able to tell what it is from a good clear photo.
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Dennis

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

I have never had any luck posting pics in this forum but I'll give it a shot again. Pic shows top lead of cap disconnected from terminal.
[img]photos/tv-149underchassis013.jpg?t=1257374779[/img]

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

One more time
[img]http://s565.photobucket.com/albums/ss95/mingram_photos/[/img]

duked · Posted: Nov Thu 05, 2009 12:21 am

here ya go
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mingram50 · Member Joined: 03 Oct 2006 Posts: 27

Thanks duked

Mr. Detrola · Posted: Nov Thu 05, 2009 12:57 am

Are you 100% certain that's a capacitor?

Micamold made some wirewound resistors which looked exactly like the part in the photo, so without being able to see the part in person, I'm leaning toward it being one of those.

The fact that you measured it at 92 ohms also seems to indicate that it is a wirewound resistor.

Therefore, a better question would be why is it overheating? Has an incorrect tube substitution been made over the years, or does one of the tubes have a filament-cathode short? You say one end of it connects to pin 3 of a tube socket, that's one of the filament pins on most 7-pin miniature tubes.
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Dennis

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

Yes it could very well be a resistor. There is another one much like it only slightly smaller coming from pin #5 of 25Z6GT which calls for a 1200 ohm wire wound.
It was not getting hot but just warm which I thought wasn't good if it was a cap but ok for a resistor. It has a nos 6J6 tube so it should be ok. I know the sams calls for a 6AU6 but the cabinet schematic lists a 6J6 and that was what it had when I acquired the set.

It doesn't make any sense that it leads to pin #3 though. OK as I'm looking at the sams schematic I see a 43 ohm res (R92)in the filament string, could it be a misprint on page 6 thats calling it C92?

Mr. Detrola · Posted: Nov Thu 05, 2009 2:14 am

Sams is well known for mistakes and omissions in data, so it could very well be.

Does the resistor you found on the schematic connect to the pin 3 on that tube? If it doesn't actually measure somewhere around 40 to 50Ω you might consider replacing it to match the schematic.
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Dennis

mingram50 · Member Joined: 03 Oct 2006 Posts: 27

Yes it connects to pin #3.
Yes I will replace it.

Thanks everyone for the replies.

ff4312 · Member Joined: 09 Jul 2008 Posts: 190 Location: Florida

Looks like everyone beat me to it.
That makes sense though, the red and brown wires right next to it indicate overheating. If my newbie knowledge serves me correctly, this would cause a resister to go up in value. Go with the tube layout that was in the cabinet. Mine didn't have one and I made the mistake of following the SAMS. No long term damage but the smoke emanating from the tuner had me sweating Shocked

-Shane-