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 Post subject: Getting started on Admiral 19F1
PostPosted: Jul Sun 28, 2019 5:57 pm 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Hello all, as of now I am currently getting into my first television restoration. I have restored a dozen or so radios, and have developed a decent knowledge of vintage electronics. I have all the basic test equipment, scope, multi-meter, signal generator, frequency counter, etc. I am seeking suggestions on what other equipment I might need to acquire to take on this television. Such as a CRT tester? As well as what I need to get a signal/picture to the television. At my age of only 20 years old I have little to no experience dealing with television antennas, or analog reception. So I am really looking for the most elementary explanation possible on how to get picture to my television. I have already started recapping, but nothing further than that. Thank you all in advance.


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Sun 28, 2019 7:56 pm 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 1839
Location: Dallas, TX
There are a couple of ways of getting an analog TV signal (technical term NTSC). The "Video Out" on
DVD and VHS players is what is called baseband NTSC video and need to be put into a TV RF modulator, here is one example that isn't very expensive.
https://www.amazon.com/RCA-Compact-RF-M ... 5337&psc=1
Just to check things out another way is to use a old video game.
A third way is to use a DTV to analog convertor box with an antenna, you can find the boxes for less than $ 30. You tune digital stations in using a remote for the box.
One thing about all the above is that they put the analog RF out only channel 3 or 4, so the vintage TV tuner only has to work (or be adjusted) for those channels.
There is a more expensive and hard to come by option called an agile modulator, that lets you change the RF channel that it outputs to any of the old stations.
Since TVs have more tubes and a greater variety a tube tester makes more sense that trying to have a stash of new tubes to try.
If you might only restore one TV then spending a lot on test equipment doesn't make much sense, but if you might be doing many then the sky's the limit on test equipment.
You would need a sweep generator to align TV IFs, but maybe you don't want to get into it that far.
A high voltage probe for you meter would be a good idea.

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It's not the Destination, It's the Journey.


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Sun 28, 2019 8:23 pm 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Thank you. I will look into those options. Probably end up using both so I can play DVD's and local channels on the set. I do have an old RCA WR-59C sweep generator that I purchased awhile back in anticipation for getting into televisions. Now as far as CRT testers I see a lot of those old Sencore sets around for fairly cheap. Would one of those be worth a buy?


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Sun 28, 2019 9:31 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Woodinville, WA USA
I would hold off on buying a bunch of test equipment until you do one TV restoration and find out whether you enjoy it enough to do more. There is an even chance (maybe better than even) that the CRT in your TV is usable, and you will learn that in the normal course of restoration, so whatever you spent on a CRT tester would be wasted for this particular project. Likewise with a sweep generator and other alignment equipment. Not every old TV must be realigned, so that equipment might not be necessary (or useful) for this project.

Here is an article with basic advice about getting started in fixing old TVs:

https://antiqueradio.org/howfixtv.htm

This page lists a bunch of articles explaining how I restored various vintage TVs:

https://antiqueradio.org/televisions.htm

None of those TVs is identical to yours, but if you skim a couple of articles, you'll learn what's usually needed to bring these sets back to life.

Have fun!

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


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Sun 28, 2019 10:51 pm 
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Joined: May Thu 14, 2015 4:15 pm
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Location: Dallas, TX
Yeah, the time to use a CRT tester is before you buy the TV. Seriously, you use a CRT tester once on a TV, maybe twice if you have to get a replacement tube.
Once you have a TV, you either commit to fixing it up regardless of cost (including possibly replacing the CRT) or you forget about it, it is up to you. If all the voltages on the CRT in the TV are good (including the HV) and there is no light on the screen then you know the CRT is bad.

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It's not the Destination, It's the Journey.


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Mon 29, 2019 3:39 pm 
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Location: Pewaukee, WI
There is a thread here on how to do a crude basic CRT test with a 6V battery a resistor and a DMM... If your set uses over $50 worth of capacitors it is worth doing that before investing in parts or test equipment (unless you have already decided you are going to buy and restore several vintage TVs no matter what it takes).

There were 2 different IF frequencies in use on TVs and most generators don't do both. 21Mhz was used on early sets ( and non-UHF models) up to the mid to late 50s. And 44MHz that was used on UHF sets and pretty much everything made after 1960.

A great multi purpose test instrument for TV is a B&K 1076/1077 TV analyst. It generates a TV test pattern and signals for signal injection troubleshooting for every stage of a set...It can get you to a solution faster and easier on many problems than any other piece of gear.


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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Jul Wed 31, 2019 5:17 am 
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Location: Belrose, NSW, Australia
Here is that thread:

viewtopic.php?f=3&t=331576&p=2776713&hilit=if+you+don%27t+have+a+CRT+tester#p2776713

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 Post subject: Re: Getting started on Admiral 19F1
PostPosted: Aug Thu 08, 2019 12:39 am 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Thank you all for your help. I now have everything I need to get this project going. Should be done recapping here soon. Thanks again!


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 Post subject: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 1:05 am 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Good evening everyone, I have just finished recapping this Admiral, and have gone ahead and powered it up for the first time. At first I was delighted to see the CRT light up upon the initial power up, but after I turned it off to go eat dinner and come back I got no illumination from the CRT. After this I started to dig in and check voltages. I first checked the normal rectifier which was fine. Then onto the high voltage rectifier (1B3GT) where I checked the filament voltage leading to the 2nd anode of the CRT. Here I found that I was getting no voltage reading. The schematic calls for 15kv. After that I popped of the cover and I saw that there was no light coming from the tube. Could this be the tube just having gone bad, or another issue related to the high voltage section? Thank you.

P.S. I apologize for not attaching the schematic. I am using a paper copy, and have not been able to find a digital copy.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 2:52 am 
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Joined: Jun Thu 25, 2015 3:21 am
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you can check the tubes in the horizonttal and high voltage section. one thing for the horizontal and high voltate tubes if the tube tests bad it is bad. if the tube tests good it may or may not be good. if replacements are available in your inventory of tubes i would change the hv tube and the horizontal tubes. if you get a raster on the screen you can put the old tubes back one at a time till you loose the raster. the last tube u put back will be the bad one. the falt you described could indeed be a bad tube. it also could be another part in the high voltage horizontal section. you can check the voltage at the points mentioned on the sam's. this fault is definately in the hv or horizontal section


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 3:56 am 
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Joined: Nov Thu 11, 2010 6:03 pm
Posts: 966
Location: Pewaukee, WI
HV rect filament is very dim and hidden so it is normal to not see it light.

If you have a CFL or small neon Indicator hold it next to the H output tube top cap and near the flyback dough but...if it flows unconnected when the TV is running then the HV rectifier is probably bad. If the gas bulb don't glow then your horizontal section is not driving the flyback properly.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 4:04 am 
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Joined: May Thu 14, 2015 4:15 pm
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Location: Dallas, TX
The 1B3GT is a special case. The filament is driven by the 15,735 Hz signal in the flyback (actually pulses) and is about 1Vrms. The filament does not glow very much and is covered almost completely by the plate structure. All of this means that it is very difficult to see the glow and to measure the voltage.
The thing to do first is see if you can draw an arc from the rectifier top cap to a grounded screwdriver. I'm not sure of the size of your CRT (and therefore the anode voltage) but typically you should get an arc about a quarter of an inch long. Another clue is whether you can light a compact fluorescent bulb by holding it near the flyback. If those tests are good and you still have no high voltage then try a known good rectifier.
Attachment:
FluorHorzE01.jpg
FluorHorzE01.jpg [ 114.2 KiB | Viewed 1131 times ]

EDIT: WHOA! It was late last night when I read your post. Did you try to measure the filament voltage on the H.V. rectifier? Your darn lucky there wasn't any H.V. You could of gotten a big jolt and blew up your meter! DO NOT DO THAT!

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It's not the Destination, It's the Journey.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 3:35 pm 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Thank you for the suggestions. I tested other voltages in the horizontal section and did not get any significant voltage. It seems the whole section is dead. I don't have a 1B3GT on hand, but I ordered one last night. I will also try that light bulb trick to verify if it is indeed the 1B3GT. If not I will swap out of tubes in the horizontal section. What would cause this tube to function fine on the first power on, but die immediately after that?

Side note: how would I safely measure the H.V. on the filament? Granted, I did bring it up gradually with the Variac, but I'm guessing with 15kv I'm playing a dangerous game. Would I need just a high voltage probe, or a different Voltmeter all together?


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 7:37 pm 
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Joined: May Thu 14, 2015 4:15 pm
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Location: Dallas, TX
Chase.Parten wrote:
Thank you for the suggestions. I tested other voltages in the horizontal section and did not get any significant voltage. It seems the whole section is dead. I don't have a 1B3GT on hand, but I ordered one last night. I will also try that light bulb trick to verify if it is indeed the 1B3GT. If not I will swap out of tubes in the horizontal section. What would cause this tube to function fine on the first power on, but die immediately after that?

Side note: how would I safely measure the H.V. on the filament? Granted, I did bring it up gradually with the Variac, but I'm guessing with 15kv I'm playing a dangerous game. Would I need just a high voltage probe, or a different Voltmeter all together?

Attachment:
ElectronTechE2.jpg
ElectronTechE2.jpg [ 103.18 KiB | Viewed 1080 times ]

I often wonder if when someone starts on a TV for the first time whether they will learn about the safety problems soon enough. The 15 KV can under certain circumstances jump up to an inch. In other words don't get your fingers any closer than a couple of inches from the horizontal output cap, flyback, H.V. rectifier or CRT anode in a running TV. Also the insulation on the meter test leads are only rated at 1 KV at best, many just 600V.
The horizontal sweep section generates the drive for the the high voltage. Most likely the horizontal oscillator tube or horizontal output tube died. Could also be a bad solder joint that held on for a time. Lots of possibilities. Just when a tube dies is not predictable.
You can get by without a H.V. meter probe, but they are nice to have for TV work. I wouldn't spend a lot on one, they originally could be had for about $ 20. Some of the pirates on ebay will ask $ 100. They are just a 990 Megohm resistor in a well insulated handle. Along with the 10 Megohm meter input reistance they form a 1 to 100 voltage divider. The meter reads (and should only see) one hundredth of the real voltage. So 15 KV should read 150 V. They are only good for DC voltage. The exact H.V. on color sets is more important. There are also probes that include a meter. I've ended up with a small collection.
Attachment:
HVProbesE1.jpg
HVProbesE1.jpg [ 181.66 KiB | Viewed 1080 times ]

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Tim
It's not the Destination, It's the Journey.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 8:58 pm 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Thank you for that. I will purchase one of those probes. I failed to mention that there is a high pitched squeal coming from the speaker which will change in frequency when I adjust the horizontal control.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 9:03 pm 
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Joined: May Fri 29, 2009 4:35 am
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Location: Chicago, IL USA
Did you check the 1/4 amp fuse between the 260 volt B+ and horizontal circuit ?


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 10:04 pm 
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Joined: Feb Wed 03, 2016 9:11 pm
Posts: 63
Location: Savannah, GA
Yes, the fuse is good. I have also gone back and verified the voltages in the Horizontal section, and it seems that throughout the horizontal oscillator, and horizontal output voltages are fine. Starting to seem more and more like it is the that 1B3GT. The squeal still persist.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 10:56 pm 
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Joined: May Fri 29, 2009 4:35 am
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Location: Chicago, IL USA
I have experienced at least once where the filament in a HV rectifier broke and a loose end shorted against the plate. Very hard to see without looking up inside the tube's plate structure with a flashlight. The short put a strain on the flyback and resulted in a squel and no HV output.


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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Thu 08, 2019 11:17 pm 
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You could use an ohmmeter to check the 1B3 filament. It would be somewhere under 100 ohms.

If you want to see if it is lighting up:
First remove the tube from the set. Find out what angle you have to look at to see the filament itself. Then with the tube in the set find out where you can place your head to see the filament. Then turn out all the room lights and turn on the set. Look at the filament. It will be a quite dim red if it is lighting.

Or you could connect a 1.2 volt battery to it. Again a quite dim red and you have to look directly at the filament.

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 Post subject: Re: Admiral 19F1 High Voltage issue
PostPosted: Aug Fri 09, 2019 1:56 am 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 1839
Location: Dallas, TX
Hoping this doesn't come to late, but since that TV is from about 1953 some of the insulation has probably become brittle. Be careful removing the tube cap connector from the H.V. rectifier and horizontal output tube.
Some damage happened on someone else's Admiral recently.
viewtopic.php?f=3&t=357195

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It's not the Destination, It's the Journey.


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