New Member, new-to-me set, new adventures!
 

Hi all,

I found this forum doing some searches related to a 1957 RCA B&W set I just picked up at a garage sale, model 21-S-7447. I'll be getting it to my place tomorrow! This will be my first vintage electronics restoration. I've worked with modern electrics though so I don't think I'm totally in over my head :stupid:

According to the seller the set hasn't been powered up in over 10 years. When last powered up it supposedly worked. Looking inside all the bits seem to be there, though the wires for the power / channel lamp are disconnected. Don't worry, I'm not going to power it on until the capacitors have been replaced and the frayed line cord is replaced.

I've tried to find service information for this set but have come up empty handed. Any tips on where to look?

Reading through the threads here it seems there's quite a few members from Michigan here. I guess one more won't hurt :)

Thanks!

-Jason

EDIT: I accidentally posted this in the color forum. Oops, could a moderator move this to the B&W section?

Hi Jason, welcome to VK!

I moved it to the B&W Forum for you.

I would try to power it up before starting the recap.
It'll probably work in some fashion and it's good to know what you have before you start so if something is wrong after you'll know if it's a new problem or an old one.

Welcome!

Cool! And welcome. do you have a front view?

I didn't take a picture of the front, I should have. I'll be sure to share with the rest of the class when I get the set to my place tomorrow.

-J

Welcome to AK!

Jason,
I emailed you the Sams Folder in .pdf format.
Jim

Welcome to VK. I like that "Panoramic Speaker System" label.

I had one that same age, similiar story. The guy who gave it to me hadn't tried it in about 10 years, in which time at least one of the filters had gone bad. (as I learned when I tried to power it up) But it was a fairly straightforward repair and the set worked well. I later sold it to another collector. Mine had the vertical chassis that wraps around the crt neck.

Oh, and welcome! If you need anything, just ask...tubes, knobs, etc, somebody here probably has it!

Got the set home.

http://www.videokarma.org/attachment...1&d=1284316024

Seems it was downgraded from a "Delux" model to just a "elux" :scratch2: It has 3 speakers in the bottom of the cabinet, a larger one pointing straight ahead and a smaller one on each side mounted on an angle.

Anyway, there's a little funny business going on inside. Looks like the picture tube was replaced at some point around 1964. One of the mounting nuts for it is missing The tube connector looks like it was glued on, and not meat to come off. On a first look it seemed loose and broken, I was worried the nipple on the end of the tube may have been damaged. As I prodded the connector it started to come apart. I've never see an picture tube with a "permanent" connector on the end. Is this normal? Also the HV lead does not have a rubber cup on the end.

http://www.videokarma.org/attachment...1&d=1284316024

http://www.videokarma.org/attachment...1&d=1284316024

http://www.videokarma.org/attachment...1&d=1284316024

-J

Ugh. That's the CRT base that's come off. It's definitely suppose to be bonded to the glass with that resin you can see the remains of. The socket that is meant to come off is the half-moon with 5 wires going to it. You're going to need to resolder and glue a base back on that CRT. I hope none of the wires have broken off.

Yes, that socket on the end of the CRT is normal. Just like an octal tube, but with 12 pins (or at least 12 positions for pins). Starting a few years later, this type of socket was no longer used on CRTs, and the socket pins came right out of the glass, like a miniature tube.

OOPS! The CRT base cap, which is cemented to the tube neck came off, rather than the CRT connector.:tears:
Sometimes the connectors are corroded, and are stuck to the CRT base cap, but with a little WD-40 and careful prying the half-round connector with the wires attached should come loose from the CRT base cap.
You should be able to solder the wires back to the base cap and repair the CRT, if the wires are not broken off flush with the glass.

Many sets do not use a rubber bootie around the HV connector.
jr

You might find this thread on repairing a damaged base useful: http://www.videokarma.org/showthread...=248393&page=2

That's a nice blond. Hopefully you can save the CRT and it test's good. I have a Beltron tester and it's one of the best to use. If it tests bad up the filament voltage up to 8 volts and let it cook for a couple hours. then retest and do the clean function.
I'm not sure what crt you have in there. the label in your picture is not the one with the Tube number. More than likely it is a number something like 21XXP4. the XX are actually numbers. It might say on the tube diagram on the inside of the cabinet. I have a couple of good 21" tubes that may or may not work. But I live way north in Escanaba.

Pix 4, (closeup of the HV connector) shows a label...looks like 21ACP4A. I don't see an ion trap installed on the tube, so I suspect the "SG" prefix stands for "straight gun", and no ion trap is needed.
jr

http://www.videokarma.org/attachment...3&d=1284316024

I saw a label on the tube saying no ion trap was needed. I have a Sencore tube tester somewhere, just need to find it. I don't think it can specifically test CRTs.

Know of a good source for another tube base? Using a little PB Blaster and some careful prying I got the connector off the base without damage. One wire in the base is still hanging on, so indexing the pins shouldn't be an issue later on.

I spent some time cleaning things up. Yes, I was careful not to scrub the makings off of the tubes. I have a friend who repairs Hammond organs who warned me about that. I have a great picture of a box of tubes from his Novachord as my desktop background, shoot me a PM and I can email it to you.

The insides cleaned up very nicely. It needs repairs to the plastic volume knob, it doesn't grip the pot at all (the metal spring part is missing). Once I get the tube base repaired I'll see if the set works!

http://www.videokarma.org/attachment...1&d=1284324102

I figured I would have to mechanically clean the PCB, but compressed air alone did the trick.

http://www.videokarma.org/attachment...1&d=1284324215

-J

Sadly I do not have any that would sub to this. It sure seems when they hit the mid 50's the number of different types sure expanded alot.

I think you could mark which one goes to which pin. Then use a soldering gun and heat it up and pull the cap totally off. Then heat each pin up, give it a smack to clean out the solder in each. then you are all set to solder it back on. The one time I did this I used some silicone and then after it dried I put some electrical tape on for further strength. I am sure there is something better tho.

My only worry is that so little of the base is left I don't know if it will be mechanically stable. Almost half of the part which would be glued to the tube is gone. I'd hate to have a wire snap off at the glass because the connector wiggled around too much.

Then again, there's very little weight hanging off the connector. Reading through things it seems people like using silicone to re-attach these. Has anyone ever tried JBWeld? I'd think that would make for a more stable bond.

Looking good!:thmbsp:

Sometimes people rob the bases off of old CRT brighteners, such as this:

http://cgi.ebay.com/TELEMATIC-CRT-BR...item20b389a528

Not affiliated with the sale,
jr

Nice Avatar!!! Do you have a Lisa?

the RCA Victor set that I have, looks VERY similar, if not the same chassis. after a recap the thing was working great, but had vertical buzz in the audio on bright scenes which drove me nuts.

now that you mention Lisa, i remember seeing a couple at the local thrift store years ago, but passed them up unknowing what they were worth. whoops.

Sorry, off topic.

Be careful using compressed air! Low(er) pressure is just fine for blowing out all that dust and won't tear apart components and labels!

Nice set! At least the neck didn't get busted and gone to air.

Just be very careful with the wires coming out of the tube base, they will break easily if bent too much.

Most of these should have five wires coming out of the tube, maybe six if it's electrostatically focused but I don't think they were that late.

I think they go in to the cap in the same order they come out of the tube, in any case the heater wires should go one on each side of the index key.

Yes, I have a Lisa 2/10 with lots of other goodies, including a working internal disk ;) But that's a story for another day. It needs some electronic restoration of its own, I'll probably detail that here when I get to that project.

http://compu85.homeip.net/stuff/lisa...VC-008F_sm.JPG

Looking at the picture tube all 5 thin wires go in order. I'll pick up one of those brighteners to thief the connector off. Unless someone has an old crappy one they want to sell me :) I hate to tear up something NOS.

Oddly enough I don't think the pilot light in the tuner dial was ever hooked up on this set. There's no lamp in the socket, and the wires for it are not hooked to anything, but were not cut off: They have a short portion stripped and tinned at the end.

-J

I wouldn't worry about getting another base for the CRT. With the bakelite broken away like that it's a lot easier to line up the leads. Lay the set on it's face to resolder pins.

General Electric CRT
 

General Electric built very good CRT's and I'll bet this one is in good shape, as late as it is.

You can fix that socket !:thmbsp:

Pallophotophone

Built a dim bulb tester and got the tube socket repaired.

Tester with a soldering iron plugged in:

http://videokarma.org/attachment.php...1&d=1298095566

Banderson suggested soldering fine wires to the tube leads. I did that.

http://videokarma.org/attachment.php...1&d=1298095566

http://videokarma.org/attachment.php...1&d=1298095566

http://videokarma.org/attachment.php...1&d=1298095566

I used some epoxy to re-attach the tube base. I think it will hold together as long as the connector is removed carefully.

I optimistically set up a mirror and flipped the switch! Sadly the set doesn't do very much. The tubes warm up, but there's no picture, no scanning sound, and no static on the speaker. I happened to get a phone call while the set was on and I did hear the "ba da da da da da" sound out of the speakers, so something in the audio stage is doing something.


I looked at the bottom of the chassis and everything looks totally original. Time to start the troubleshooting tree, though I'm betting it's capacitors.

-J

Nice job repairing the CRT base :thmbsp: I imagine you have a few bad caps too.

Those are some funky looking light bulbs. Are they specialty or vintage bulbs ?

The large ones are "industrial service" lamps. I got them at the U of M salvage store for $0.10 per pack! They had some nice 1980s 25w lamps too, some from ITT and some GE ones with a picture of Edison on the side of the carton.

-J

So I played with the set some more tonight. I left it sit for a couple hours with just a 40w lamp in the tester, giving the tv about 30 volts. I then put the big lamps back in, and heard scanning! I plugged the set into line voltage, and amazingly there was sound! Not just static, but an actual broadcast! I guess there's still some analog transmission in this area.

http://videokarma.org/attachment.php...1&d=1298095417

The picture is very wrong. It does seem to change with the channel selector, but not much. The upper half is dimmer then the lower half. There's also a very noticeable high pitched sound. I don't know if that's normal for older sets, but I have good hearing and can pick up a modern set when it's left on with no picture.

I turned the set off for a moment while I got a light so I could read the controls, but when I powered the set back up there was no picture, no high pitched sound... just audio.

EDIT: The station is from across the border... CBC on channel 9. The audio stages work perfectly, the set has fantastic sound.

-J

looks like your video amp tube is bad, or voltages not right there.

The worst is over. You have a raster, the CRT works, the HV flyback works, the yoke works. Now as suggested, some paper capacitor replacement and electrolytic capacitor replacement will quickly bring this old girl back to life.

Top of the picture may look dark because the scan lines are so far apart. Vertical linearity is way off but that could have been from someone monkeying with the control or more likely, bad caps in the vertical section.

Congrats and welcome aboard Mate!

So I'm going to the electronics store today to buy caps. Looking through the pictures in the schematic I noted all the ones that looked like paper. In the parts list I notice some of the caps have a voltage listed, some do not. Why is this?

EDIT: looks like the paper ones are the ones with a voltage rating. Easy enough.

-J

Yes just start with electrolytics and paper caps and see what that buys you. Don't worry about micas as yet, since you may get very good results by just changing these out. Keep us posted!

Gilbert

I've gotten the chasis out, there's trouble in river city. Looks like I was too hasty in my initial powerup, the vertical output fuse (.3 amp) is blown. The flyback also looks like it got toasty at some point and dripped a bunch of wax into the bottom of the cage.

I didn't have the set running very long when I got a picture, and I've never smelled any bad smells from it, I wonder if the flyback melted years before?

Someone was nice enough to scan the Sam's for my set, but I think it's missing a page in the schematic section.

:/

-J

So how fatel does this look?

http://videokarma.org/attachment.php...&d=12980925313

The lead going to the top of the HOT had a very shoddy repair done to it, the last few inches of the wire had been changed to lamp cord with a very poor solder job on the tube connector. The part where the wires were joined fell apart. It may have just been twisted together with a single turn of electrical tape to cover it. Doesn't that wire cary very high voltage? Can I replace the damaged end if I use good wire and cover it with layers of heatshrink?

Start of the evening. I don't think a single part has ever been replaced.

http://videokarma.org/attachment.php...3&d=1298092531

A few hours later, a bit of progress. So far the caps match the Sam's.

http://videokarma.org/attachment.php...4&d=1298092531

I was annoyed when I found the modules were soldered in place, but less annoyed when I found you can reach most everything through holes in the chassis.

Now that I've supported my local electronics store, I think I'll get the remaining caps online. Electronic Connection seems to add a ~$2 markup per cap :sigh:

-J

One more question... I need to clean between the CRT and the safety glass. What's the best way to get the CRT out of the cabinet safely? Lay the whole thing down on its front and get a helper to help grasp it by the mounting ears?