A friend of mine gave me a muntz tv. The cabinet is in rough shape and is in pieces while my friend restores it. The original back is missing so I have no idea what model number it is. It has a 16" crt and the tv history website shows 16" muntz to be 1950 or1951.

Can anyone help me identify the model number in case i need a diagram for the few parts that are actually in it?
When I look up pictures online of muntz sets they pretty much look the same.
They either have 2 knobs on the front or three.

OK...how many knobs does yours have? 16" round or rectangular? A pic is worth a thousand words.

Two knobs in the front. 16" rectangular picture tube. No idea which crt it has since there is not a number on the glass neck and the paper tag has been half rubbed off. I will take a picture of the chassis this weekend. So we will probably have to go by tube count and placement then?

Muntz chassis general layout didn't change a whole lot in the first few years. 16" rectangular definitely zeroes in on a 50-51 time frame. I'll take a look in Rider.

Is the chassis marked TV17A3 anywhere? It could be model M32. Sixteen tubes using a 6BG6 for sweep with a separate oscillator but no phase detector.

It does have a 6bg6 tube. mine has a 6sn7 behind the high voltage cage and the 5u4 is to the left of it. I want to say it has 15 tubes plus crt to make 16. The chassis is at my friends house.

There was a serial number on the back but it is 12758.

It does have a 6bg6 tube. mine has a 6sn7 behind the high voltage cage and the 5u4 is to the left of it. I want to say it has 15 tubes plus crt to make 16. The chassis is at my friends house.

I've seen a few of those early Muntz's that had a 6F8G, instead of a 6SN7. It's on the IF strip side. It looked strange to see a ST type tube, with a grid cap, in a TV set.
The set uses the synchoguide circuit in the horizontal oscillator stage, that doesn't need a phase detector stage.

I will take pictures of the chassis and post them tomorrow afternoon. I guess I should have posted this question AFTER I had a little more info.............But every time I get a new project I go nuts until it is taken care of.....almost an obsession!.......Its pretty much all I can think about......Anyone else get like this??

I will take pictures of the chassis and post them tomorrow afternoon.

Attached is the schematic from Beitman's on the chassis that Muntz used in 1951 for many 16 and 19 inch sets.

If this is the correct schematic, shoot me an eMail and I'll send you a B&W scan of it and the two other pages (no chassis layout) next week. That higher quality scan will be well over the size limit.

Sorry for the quality, but I first sent a highly compressed 400K image and VK shrunk it to 1/8 width, making it unreadable. Will try two half-width images, although it takes more bandwidth and see what happens.

............But every time I get a new project I go nuts until it is taken care of.....almost an obsession!.......Its pretty much all I can think about......Anyone else get like this??

Actually, I'm accused of researching too long :scratch2: before starting my restorations.

The next set on my restoration list was purchased in December of 1966.

No, it is not that bad!

In 1966 I paid $15 for a non-working Pilot TV-37 and immediately repaired it and used it as my daily driver until I bought a 15" Sears (reranded Toshiba all-tube) as soon as NBC started televising the space shots in color.

That little 3" set was still working fine, when I last turned it on in 2010, but unfortunately it took a swim when my basement flooded a year ago. I hosed the red mud off and it has been sitting in my garage drying out ever since.

Now, what I really go nuts on is lousy internet service! When I lived in Ohio, I had Lima's own WCOIL (Western Central Ohio Internet Link) which I affectionately called "Water Closet OIL" and sorely missed it after moving to Virginia. Thanks our current phone company's refusal to install copper phone wires, or paying more for the phone company's internet than my house payments, I'm limited to Comcast which offers one quarter the service at twice the cost of WCoil.
Jas.

well, that was not my set. mine does not have a 12at7. If my internet connection will cooperate I have a hand drawn tube layout. Also I found 16a2 stamped on the chassis under some dust. Is that it?
Thanks!

Well over the weekend I recapped the set and put the tubes back in with nos for the bad ones and guess what...... I left the 6w4 sitting on the counter at Fair radio..... So now me with zero patience will need to wait til monday to try out my handy work !

I don't know why I thought you said your set was a console. M31 is the 16" rectangular table set with 16A2 chassis. The unmarked tubes in your diagram are (from the top) 6AU6, 6T8, 6AU6, 6AQ5. It's a very early rectangular set from 1950.

I forgot, mine is mounted on an optional base. It is a table top. even has chrome feet that you can see if you look in and up at it from the back. I will get a diagram but for now what crt does it call for?

Also, Should the crt have one of those rings with a magnet on it. I "think" it is called an ion trap?This tv besides missing the back seems to be unmolested.

Well I took the last tube and put it in and so far the set is picking up a fan and sending noise to the speaker and I can hear the horizontal noise from the flyback but the screen is dark.I went through most of the resistors with my ohmeter and most are way off. and the video detector diode reads 4,000 ohms both ways so I still have more work ahead of me.

So now My rectifier tube is lighting up like it is shorted. I tried other 5u4's and same problem. I think one of the electrolyitics went out. They were new but I tried to form them on a cap checker I was not used too. If there is anything else that would cause this tube issue please let me know.

Also the screen did light up before this tube issue. The magnet on the back of the crt was missing and I put one on and did get a horizontal line on the screen. the vertical is out and i am not sure why. I did get a diagram and found a bad resistor in the vertical circuit. Plus I need a 4,000 pf cap in the vertical circuit and the closest I had was 5,000. So maybe it is not letting the circuit osc. at the right frequency.

So far this tv seems to be one step forward and one step back.

So my biggest concern is the shorting out rectifier tube. I have three good ones and all start to light blue. But not in my capehart radio which uses them. So it is the tv.

I do not know what else could be the problem besides electro's. I checked the filter choke and audio, vertical and other transformers as far as resistance and they check fine. the main transformer does not have resistances listed but this set did put up a horizontal line on the screen for about 3 hours before the shorting rectifier tube started. It started on fire up last time I tried the set.

Any ideas please post them!

It sounds like one of your Electrolytics has shorted, you certainly have a short on the B+ line somewhere.

If they are new then double check to make sure you put them in correctly (Polarity).

This is really one of those times you need a Variac to keep from blowing your Rectifier tube.
You can rig up a Solid State replacement for testing purposes but it will increase the B+ so you don't want to run it at full voltage lest you explode a shorted Cap.

If you can run it on a Variac you can feel the Caps and see which one is getting warm, or disconnect them one at a time until the short goes away.

Another possibility would be that the focus coil could have shorted to ground.

jr

It sounds like one of your Electrolytics has shorted, you certainly have a short on the B+ line somewhere.

If they are new then double check to make sure you put them in correctly (Polarity).

This is really one of those times you need a Variac to keep from blowing your Rectifier tube.
You can rig up a Solid State replacement for testing purposes but it will increase the B+ so you don't want to run it at full voltage lest you explode a shorted Cap.

If you can run it on a Variac you can feel the Caps and see which one is getting warm, or disconnect them one at a time until the short goes away.

I have run it for about 3 hours before this short so I pull electro's and am going to test them this week. hopefully it is not the focus coil.

Another possibility would be that the focus coil could have shorted to ground.

jr

I don't remember seeing any wires for the focus coil seperate from the yoke. Should I?

Also I am curious. one of two things was happening. Either the rectifier tube was getting shorted or a ten watt 2500 ohm resistor was arcing to the chassis. It is one of those long metal resistors that is mounted onto the chassis and has a flat piece of metal that is folded over to cover it. If the rectifier tube did not short the resistor started arcing to the chassis itself from the wires inside of it. It had two leads so it was not grounded per se. Could this be the culprit?

I did take my electolytic caps out and test them at fair radio. I could not find a heathkit cap checker which I am used to. I had to use a sprague but I am not sure if it is functioning perfectly. That being said two of the 100mf caps seemed to not form right. On the 6ma. setting they held 150 volts instead of dropping to zero as they charged up. I grabbed 2 more and they did the same. I went to the bin and opened a new bag and they dropped down to about 5 volts or so. Plus after they were charged they had a loud snap if I shorted them on some metal and the first set really did not snap very loud. I am hoping this is the problem ......Really wish I had the heathkit checker because I know how to "read"it.

It is possible that your model does not have a focus coil. Perhaps a permanent magnet focus assembly is used. The only sams that I could dig up for a Muntz of that period was for models M-31, M-32, M-33, and the focus coil is clearly shown.

I don't trust those chassis mount resistors at all... I have seen several that have shorted to ground, so that indeed may be the problem... That can get exciting!

jr

I think this is a m-31. I do have the diagram but it is at my friends house along with the set.

Fair Radio does have a heathkit cap checker.... it was hidden in the back(where I was at earlier). I will go back in tomorrow and use it to double check my caps so I am confident about their condition before I put them back in. The Sam's should be 108-8. if my memory serves me correctly

The Sams that I am looking at is 116-10, so perhaps it is a different set... I don't see a chassis mount resistor in the pictures, but the wires for the focus coil are clearly visible, behind the yoke.
Must be nice being close to Fair Radio ! :)

jr

My set has a chassis mount resistor in the high voltage cage. Yeah having Fair in the neighborhood is cool. I worked there as a second job and liked it but quit due too being tired as my first job had overtime a lot. But going in early monday morning and being the first to go through their auction purchases was the best!.

I did check just now and my set is Sam's 108-8.

I just got to thinking that maybe the wires for the focus coil run through a different hole in the chassis so I will have to check for them sunday on my next day off.

Well I retested the caps on a heathkit cap checker that I went through and recapped, replaced out of tolerance resistors and calibrated.
They all check good...... that being said 2 of the 100mf caps that I originally used did form very slowly. The newer ones formed quick.

So I guess I will replace the chassis mount resistor and check the focus coil although I am not sure how to check it right now. The tv itself is in another town at my friends house and I called him and he stated that there are only 4 wires going to the yoke and not 6. So I am unsure how the focus coil is hooked up.
If my memory serves me correctly the diagram showed a coil and(or) a permanent magnet assembly for focus but did not show routing of wires but when I look at the yoke it appears to have a narrow coil in front of the deflection coils.
Oh well if this hobby was easy more people would do it....right?

Well I got this set running. Yeah! The 2,500 ohm chassis mount resistor was shorted to ground. The picture tube did check like it is alive but was not strong...

What's funny is there is a burn in the screen....took me a while to figure out what it was but it appears to be a tv station test pattern . A circle in each corner and a dark spot in the middle! So now I need a 16rp4 crt. Wish me luck!

Oh, One last question; Does a crt lose its contrast capabilities as it gets weaker?
The picture did not impress me as far as how white the whites were.