Motorola 14P3 restoration
 

I picked up this set along with some other vintage gear a few months ago and promptly forgot about it. A few days ago I was cleaning out the garage and stumbled across it. I figured this was a good a time as any to take a closer look.

It sure is dirty :yuck:
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Specifically, it's a Y14P3-2. The -X part indicates the cabinet style.
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I'm not sure if any of these are the correct knobs.
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It's looking a little more respectable after some cleaning.
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Here's what I found inside. Aside from some dirt and cat hair, it looks OK.
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Time to check that 14RP4 CRT.
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Uh-oh!
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Ah shoot, the tube is dead, well guess you'll just have to part it out now.
I'll take the safety screen. :D

Are you sure it's a RP4? I have the old 14QP4 from my Philco Transitone, it's kind of weak but it makes a pretty good picture.

Oh, I'm not giving up that easily! The filament is glowing nicely - there are just no emissions. So I tried the old cathode re-welding trick and after about a dozen whacks got it to stick :)

Yes, it sure is a 14RP4. Those "lumps" on the top and bottom seem kinda odd.
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There's not much to this set and I hope to fire it up later tonight :yes:
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If anyone is curious, this is the cathode welding procedure I used.

http://www.videokarma.org/showpost.p...4&postcount=30

Cool, you got it working, I wonder if those Lumps are there to give the glass some strength? Looks like an early attempt at a higher angle deflection tube.

I have this same set in Pink, it almost works, at least it lights up fully but doesn't seem to pick up anything.

I've seen those lumps on several Zenith sets I've worked on, I too have wondered what they're for.

Good job on getting that tube going, the CR 70 is awesome. Looking forward to seeing that CRT light up.

I finished a quick recap and tried to power up the set - nothing. I traced through the filament string and eventually found a tube that wasn't seated fully.
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Bingo! I have a nice bright raster :) Now to try feeding in some signals.
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got the 14 inch motorola as well, lumpy 14 inch tube awesome picture. heck i got 2 more 14 inch crts in the garage on a pair of emersons i never fixed due to lack of caps and knobs..

SR

It's not the greatest picture, but I'm getting there :D
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That's a neat little set. Glad you got that CRT working again!

Other than reception its hella sweet mine has a small ripple in the pic, then again i didnt change that main silver electrolytic because its hard to tell which pin is which the print is faded and hard to tell the shapes appart..

SR

hay im glad to see you do that ,iv had a motorola for some time that the crt is dead like that and i have been keeping it hoping some day to run across another crt that good, can that procedure be done using a b k 467 or sencore 133 if so id like to try to bring back to life. 17cfp4 crt the label says, i dont know why someone bent the tuner cover up like that, i just put it away after testing the crt . i just checked the crt and woke it up and wiggled the horz. osc. tube around and it came on. looks like just needs recap and tube sockets replaced or tightened up.

Back in the day, everyone used big-can spray tuner cleaner, and they obviously misplaced their little squirting tube before doing this set.

This butchery is very common on tuners where the cover was soldered in place for better shielding.

I've worked on lots of sets that were missing the tuner covers. If I had one that would fit, I'd put one on before the set left me.

The things that some shops did... Amazing.

Glad you got the little Motorola going. I saw few B/W Motorolas in my time.

HOLY SMOKES SNELSON what model motorola is that in those pics??? My FIRST tv was this type (Non UHF and different color scheme) Been huntin for that model for a Loooong time.. Could have sworn mine had the 16" CRT could be wrong, i was only 8.... :D

This and a 17p6 were my two first motos... Hope to snag a pair if they ever surface...

SR

I had a Motorola 14P3 like that in the early 60's. I could not get the vertical size to work quite right. It looked pretty good and I sold it. Mine had UHF and a cascode tuner, but only two stages of IF. The set you show has the correct tuner knobs, but the rest are incorrect. It was still a better set than the GE, of the same time.

I think I'm down to two major issues with this set.

One, there's a loose connection somewhere - probably the tuner. If I tap on it, I can eventually get a decent picture.
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Two, as the set warms up the vertical height increases. It takes about five minutes to finally stop growing. At that point, I have to turn the height control all the way to minimum and it's still a bit too tall.
Notice the logo in the lower right isn't even visible anymore.
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While taking these photos, I also captured this moment. How could they spell "Cheers" with only one "e" :no:
http://farm9.staticflickr.com/8018/7...00d8ae58_z.jpg

thats when they used the ole Mc donald tune and they couldnt use both Es :D

i didnt think its a 17 either but thats what the schematic said, i didnt look any further though unless the lable covers both models ,how interested in it are you ,iv got it just waiting till i get done with other projects. im getting to many b&w tv's i lately ,i have a guy sending me a porthole with a freind that works here mybe this weekend.

Have you cleaned the tuner?

Phil Nelson

LOL - I just saw that clip again with sound. I get it now :yes:

No, not yet. I'm not quite sure how to pop it open for cleaning.

i know just look in back of my set, just take a pair of needle nose plyers and and open it up like a sardean can. l o l

Luckily, I don't think it will come to that. The problem seems to be a flaky local/dx switch. I think I'll just hardwire the antenna jacks to the tuner.

Check to see that there's no isolation network in that circuit. I just used to jumper out the switch.
Doe's that set use the penthode tuner? 3CE5

There are only resistors on the switch. It has a cascode tuner using a 4BQ7.
I found a 4BZ7 installed (which is a valid substitute) and have since replaced it with a 4BQ7. I didn't notice any difference.

[img]http://farm8.staticflickr.com/7257/7...5e6d7438_z.jpg
005 by bandersen, on Flickr[/img]

After looking at the rear pictures in entry #2, I see the isolation network, is right next to the tube neck.
I had almost the same problem with the vertical size changing, as the set warms up. After years, I wonder if the problem was the thermistor on the yoke. :sigh:

I don't think there's a thermistor on the yoke - at least it's not shown in the Sams. I swapped out the 12CU5 VO tube and the vertical seems better now.

Are you sure the tuner is the problem though it "looks" like snow? Maybe its grainy due to an IF or trap mis-alignment.

I used to have a substitute tuner in the shop that would eliminate the tuner if it was not an AGC voltage issue.

That's 50 years ago. That was the first thing I did was sub the tubes. That set was only 5 years old at the time. Then caps and resistors.
Wasn't that many of those sets around at the time. A lot more Admirals and GE's. :thumbsdn:

you work on lot of these set's ,have you ever replaced the selenium. rec before with any modern diodes before , and if you did how did turn out.

I replace selenium rectifiers with type 1N4007 diodes, which are more than adequate and work fine. They cost a few cents. Take the old rectifier completely out of the circuit (don't bridge the diode across it).

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

Yep, It's that easy. I leave it in there for looks but totally out of circuit.

oh no i never leave any old comp. behind if it bad it goes, is there in some application a resistance issue ,like there was more of a voltage lost across the old rect. than in the modern diodes so that you would have to add a resister so the output would match the old rectifier. i see that 1n4007 has 50a surge but opperates at 1amp is that all that circuit draws is under a amp of current.

Yes, I always replace the selenium rectifiers with 1N4007 didoes. I then check the B+ and add a dropping resistor if it's too high.

I also like to replace the series filament dropping resistor with a diode or capacitor when possible.

i was wondering about that being half wave rec. with the resistance the early ones have ,the full wave ones are touchy when they get older and if there mountings loosen or become rusty they will cook them selves slowly building resistance internaly ,i build large 100amp or more bulk charger's when you use modern rectifiers it makes the older transformers so much better ,i have a picture of the last selenium rect i replaced, or removed to build my own type of bulk charger, all i really wanted was the step transformer out of the old unit. this is a 100amp prob. more but i cant id it i just wanted the trans. probley changing that rect. in that tv to a modern diode makes it alot better less distortion in the d.c. doesnt it .thanks

Wow, that's huge!

I've been experimenting with replacing the selenium rectifier. Through trial and error I determined that using a 1N4007 silicon diode plus a 12 ohm, 5W resistor produces the desired +125VDC with a 120 VAC AC line voltage.

That got me thinking that if I could bump the existing fusistor up from 3 to 15 ohms, it would make a cleaner modification.

Well, I didn't have any on hand, but I do have some modern 4.7 ohm fusible resistors so I combined that with a regular power resistor.
While I was at it, I figured why why not add the diode too ?
It works fine, but the diode is getting pretty hot so I think it might be best to relocate it away from the resistors.
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how many watt is the small resister ,in the picture it looks like a 1/2 watt one, if it is i wonder if that is contributing to the diode heating up . how much is the current draw is on that circuit ,i think the 330v supply on my zenith iv been rebuilding is about 450ma you might just need to up the small resister to 1 watt and see if the diode stays cooler . does the diode heat up fast or does it take alittle time. its looks like a neat idea does it plug into a base socket that easy to get at, if it does you could put everthing on a small breadboard and have the two prongs sticking out the end and it could be a fusible filter setup that can kwick change out.

The smaller one is a 2W fusible resistor. It's made out of ceramic and is designed to take the heat. After a while though, I discovered that the solder was melting!
Probably should use a high temp solder like silver solder.

It's drawing about 400ma so I figure that little 4.7 ohm resistor is putting out less than 1 W.

I decided to just use one of those old 7.5 ohm globar fuse resistors and locate the diode near where the older selenium rectifier had been.

is normal for that to run that hot that it would start to melt the solder ,i think it would burn out before that you know ,i like how they named that resister [ glo-bar ] i have seen them after they have been hot and darken the outside in older stuff , i hope they dont glo before they blow l o l