View Full Version : RCA model 21-0-845


TinCanAlley
08-16-2013, 01:44 PM
Okay, this might be out of my league, but I'm going to ask.

I have an RCA ('56 I believe). It's sitting unused because of an issue I don't know how to solve. When I tune in a station (using an RF modulator) I can tune it for a good picture or good sound, but not both. I usually end up in between the two, but it's not worth it.

My mom really loves putting on the old B&W movies during the holidays, so I'd like to try and get it fixed before then.

Any thoughts? Will it require special equipment?

Thanks

Username1
08-16-2013, 08:08 PM
The first thing you need to figure out is, if its the tv, or the modulator. So does the set still have the same problem with a different signal source? vcr as source ?

Is the model number correct ?

TinCanAlley
08-16-2013, 09:08 PM
The first thing you need to figure out is, if its the tv, or the modulator. So does the set still have the same problem with a different signal source? vcr as source ?

Is the model number correct ?

I've tried 3 different modulators and a VCR. The problem is the same with all of them. It's like the tuner for the video and audio are not in sync (if that makes sense).

I got the model number off of the back of the set and it seems the 0 is actually a D and the 8 must be a 6. The model is 21D645 (kind of hard to read after all these years). I'm attaching a pic of it. Don't mind the grill cloth, the cat had an issue with it (after years of walking past it). I'm looking for new, but the size is an issue. Most cloth isn't wide enough.

rca2000
08-16-2013, 10:56 PM
Cabinet layout looks a lot like a CTC-5, other than the tube...

Username1
08-17-2013, 08:44 AM
This tv needs a minor adjustment to the sound if detector coil. I am attaching a file I got off the internet, its a schematic for some admiral tv. You will need to make the adjustment called "4.5MC Sound IF Alignment". I can't find the one for your tv, but you should get your schematic off ebay, should be around $12. It will have an alignment similar to the one in this file, but will have the location of the coils on your tv.

This is an adjustment you can make with your signal source, just set the tv for a clear sharp picture, then adjust the sound coil. follow the directions, warm the set up.

You can make this adjustment as long as there are no other problems with the set. No drifting of anything over time, sound does not get better, or worse if left on for an hour.

Also you will need the plastic alignment tools, they are about $12. on ebay.

http://www.ebay.com/itm/GC-Radio-TV-Alignment-Tool-Kit-Assortment-6-pc-Set-NOS-/111131316111?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=iCJOYXB6zRWYIyum4vHQQCf0VqY%253D&orig_cvip=true&rt=nc

Be sure you make the adjustment carefully, the coils are delicate, most likely brittle too. Turn them as directed, but if there is no change put them back to the spot you started from, and be sure you have the right one....

Don't turn random coils if it does not improve.

Why did this happen....? Some component most likely is changing value, if its going to keep changing you will have to find it and fix it... there is a chance, however that it will not change again any time soon, so this will fix it for years to come.....

Good luck....

TinCanAlley
08-17-2013, 11:51 AM
This tv needs a minor adjustment to the sound if detector coil. I am attaching a file I got off the internet, its a schematic for some admiral tv. You will need to make the adjustment called "4.5MC Sound IF Alignment". I can't find the one for your tv, but you should get your schematic off ebay, should be around $12. It will have an alignment similar to the one in this file, but will have the location of the coils on your tv.

This is an adjustment you can make with your signal source, just set the tv for a clear sharp picture, then adjust the sound coil. follow the directions, warm the set up.

You can make this adjustment as long as there are no other problems with the set. No drifting of anything over time, sound does not get better, or worse if left on for an hour.

Also you will need the plastic alignment tools, they are about $12. on ebay.

http://www.ebay.com/itm/GC-Radio-TV-Alignment-Tool-Kit-Assortment-6-pc-Set-NOS-/111131316111?_trksid=p2047675.l2557&ssPageName=STRK%3AMEWAX%3AIT&nma=true&si=iCJOYXB6zRWYIyum4vHQQCf0VqY%253D&orig_cvip=true&rt=nc

Be sure you make the adjustment carefully, the coils are delicate, most likely brittle too. Turn them as directed, but if there is no change put them back to the spot you started from, and be sure you have the right one....

Don't turn random coils if it does not improve.

Why did this happen....? Some component most likely is changing value, if its going to keep changing you will have to find it and fix it... there is a chance, however that it will not change again any time soon, so this will fix it for years to come.....

Good luck....

Thanks, this sounds doable. I found the SM online from Photofacts and will order the PDF version of it.

I have a set of plastic alignment tools coming already. The set I have didn't perform well and wouldn't fit some Zenith coils at all. You live and learn.

It might be a week or so before the tools get here. I'll post when I start the process.