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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Wed 21, 2018 11:21 pm 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
I will take a few photos underneath the chassis tonight. I haven't looked yet. Big question, what are the chances that this thing was damaged when it was turned on? I'm getting worried after reading those last few comments.


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File comment: as it sits with my inherited broken clock that I need to learn to fix...
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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Wed 21, 2018 11:50 pm 
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Posts: 441
Re the DBT:

About the only thing that could be checked at this stage with the DBT is the power transformer for a short. You have to remove the rectifier tube(s) first. If the power supply E-caps are bad, and chances are about 95 % they are, they could pull excessive current through the transformer and rectifier tube and damage them. The next step is replacing the E-caps.
Also don't build your expectations too far, the CRT might be bad. Testing that is a separate matter.
I know there are ways of doing this with a few common test items but I'm not sold on that idea. A CRT tester is the best approach but a CRT tester only tests CRTs so that isn't a good investment at this point. Here is where knowing someone in the area with a tester is useful.


I've used the method outlined on 12 TV chassis now with generally good results for a particular brand of electro (Ducon). Another brand (UCC), results were so bad I now replace them on sight. Being in the US and not Australia, your results could be different.

The Dim Bulb will protect your transformer/rectifier from a shorted electro or indeed any B+ short. Guaranteed. That's the idea of it really.

Using the simple CRT tester I outlined in an earlier post, I have now tested more than 20 CRTs ranging in age from 60+ years to 40 years old, mainly in working old TV sets. 70 degree, 90 degree and 110 degree, mag focus, electrostatic focus, sizes from 10" to 25". The voltage reading I get (0 to 4 volts) has been a very good indicator of the tube's performance.

Here are some actual results from my measurements:

4 volts = a very sharp, bright picture. (21" 90 degree Miniwatt rebuild from 1974)
2.5 volts = still a good picture, not quite as much headroom as a "4". This one got a lot better over an hour or so running (23" 110 degree original Thomas from 1967)
1.5 volts = OK in a room with subdued light. (This TV is now in daily use in a museum and seems to be improving with time. CRT is a 17" 90 degree US made RCA from 1957)
1.4 volts = Surprisingly bright for the reading but this is an 11" 110 degree unknown brand CRT from 1964. A bit of flare on highlights. I use this tube on the bench as a chassis test CRT.
1.2 volts = OK in a room with subdued light. (17" 70 degree mag focus Thomas rebuilt CRT from 1958)
0.5 volts = you can see a good picture with the room lights off. Whites start to invert when driven hard (Miniwatt AW53-88 same as 21CEP4 from 1959)

So, it would be worth testing your CRT immediately with this method. If it's bad, that gives you plenty of time to find another one. And you can decide if you really need to. As indicated in the post, leave a weak CRT on test for a few hours and see if it improves. Most tubes that have been cold for more than 40 years do.

You need to buy a digital multimeter anyway and it will be your most frequently used tool.

Speaking of tools, here is what you'll need. (no need for specialised tools unless you plan to attempt a vision IF alignment or similar - you should not have to do this)

1 x digital multimeter (indispensable)
1 x temperature controlled 80 or 100 watt soldering iron with a medium to large tip. Japanese-made GOOT brand is recommended.
A roll of resin cored solder with LEAD in it! You should look for 60% tin, 40% lead. Avoid lead-free solder, it's too frustrating to use on old gear.
A quality pair of medium-sized sidecutters
A set of insulated clip leads
Screwdrivers
Small socket set
A flat file
A large plastic knitting needle.

An oscilloscope is useful sometimes but by no means essential - although the USB-based scopes you can plug into your laptop are cheap enough.

And that should be all you need!


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 12:02 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 441
Don't worry too much, I suspect your TV has mostly survived the onslaught of full power!

One more thing - hazardous substances warning!

Lead and cadmium do nasty things to your brain over 20 or so years. They mostly didn't know this 60 years ago and your chassis might be cadmium plated. (or it might just be another equally hazardous substance, nicotine!)

Either way, wash your hands thoroughly after handling the chassis and the lead-based solder before touching food and you'll still be able to help your grandkids with their homework!


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 12:21 am 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
Wow man thank you so much for the tool list! I will start assembling the tools. Is there a cheap way of testing the vacuum tubes? Also, what are your recommendations on cleaning the chassis? One thing I get a lot of satisfaction in is cleaning things meticulously so I can't wait to do that this weekend. Is there anything OFF LIMITS when it comes to cleaning? Anything dangerous to touch? Like I said, this thing was recently powered on momentarily.

Main concerns: I don't want to get shocked
I don't want to destroy anything by using incorrect cleaning agents.

I will NOT be spraying this down with a water hose or anything like that but some scrubbing with small brass and synthetic brushes. I want to eventually make it look like a showpiece inside and out. I don't know if I will ever do another but after the effort of learning this stuff, I have a feeling I'm going to get hooked.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 12:32 am 
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Location: Chicago, IL USA
Sure looks copper plated to me. I wouldn't use anything more than a soft brush, compressed air and a slightly damp rag to clean it.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 1:00 am 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
Thanks bandersen. Do you think I will have any fear working around the CRT or any other components?? Everyone tells me that I'm going to die if I touch it in the wrong spot and they evidently take 9 thousand years to discharge on their own.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 2:13 am 
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dandypanty wrote:
Thanks bandersen. Do you think I will have any fear working around the CRT or any other components?? Everyone tells me that I'm going to die if I touch it in the wrong spot and they evidently take 9 thousand years to discharge on their own.

The CRT can hold a charge for a few days to perhaps a week.You won't die if you get zapped, but you are likely to use your whole vocabulary of bad words and are likely to drop anything you are holding.

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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 2:26 am 
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Joined: Feb Mon 19, 2018 11:33 pm
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Location: Lafayette Louisiana
Thank you Tom. I'll get the cuss jar ready just in case.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 2:28 am 
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Location: Ann Arbor, MI
All you have to do is discharge the CRT. First find that well insulated wire that comes from that big can and goes up to the side of the CRT. It usually ends in what looks like a large suction cup. Get a screwdriver and attach a wire to it. Attach the other end of the wire to the chassis. Slip the screw driver under the suction cup until you touch the metal connector. Sometimes the CRT will partially re-charge somewhat, so keep the screwdriver there for a half a minute or so.

The power supply caps, when in good condition, can sometimes hold a charge too, although at a much lower voltage. A wire between the chassis and the first filter, (the one connected to the rectifier) will discharge it. Normally, when the set is working properly, the circuits in the set will draw the charge out of the filter caps.

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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 3:03 am 
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Joined: May Thu 14, 2015 4:15 pm
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Location: Dallas, TX
Wow, that set looks more like my Admiral that I expected.
I second the opinion that the power up probably didn't harm the transformer if it was brief. The rectifier tube might have been effected but that is easy to replace.
Soft (paint type) brush, compressed air, vacuum cleaner, all good. I like to use a window cleaner (Windex type) and paper towels after the dust is gone, it doesn't add to the residue. Your chassis is probably copper plated like mine. There might be corrosion that can't really be fixed easily.
I would caution you about cleaning the tubes, the numbers on them are very easily removed, even the moisture/ oils on your fingers can remove the printing. Dusting the tubes is OK, but I try not to even put my fingers on the tube numbers.
The biggest danger from the set right now is the CRT itself. It is a large vacuum bottle, that means there is a force on every square inch of about 15 pounds. CRTs can implode. The pane of glass on the front of the cabinet is to protect people in case it implodes. They don't always implode if the glass CRT cracks but if it happens while the CRT is exposed you could get a face full of glass shrapnel. The glass is thickest on the screen front and thinnest on the neck. I happened to take some pictures when I removed the CRT from the chassis on mine. I probably overdid the protection and I'm sure some here will get a chuckle, but I didn't want to bleed out.
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The rubber that lined the metal straps at the front of the CRT was stuck to the glass. I genitally pried it loose with a dull thin knife. You have to maneuver the neck through the yoke.
Again it is best to start smaller with radios.

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


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 3:06 am 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
That's perfect. I will definitely discharge it before going to town


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 3:23 am 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 1074
Location: Dallas, TX
Well, I may as well post the last couple of pictures of my Admiral. I boxed up the somewhat weak CRT and it all has been sitting in my garage for years. It is near the bottom of my to-do list.
The cabinet on mine has photo wood grain plastic laminate on the top and sides. Someone had spilled a solvent on the top that ruined the finish.
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It's not the Destination, It's the Journey.


Last edited by Notimetolooz on Feb Thu 22, 2018 3:28 am, edited 1 time in total.

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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 3:27 am 
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Don't worry too much about stored charges, as others have said they should have all leaked away by now.

It's not a bad idea to wear safety goggles when handling the tube. That one is a whopper - 21" 70 degree! We hardly ever saw those here (only one TV model ever) and my guess is they'd be rare there too.. But as long as you don't handle it by the neck you'll be OK. If it does turn out to be bad and you can't find a good one you do have the possibility of replacing it with the newer and much more common 21" 90 degree tube. Time to test it!!

As far as cleaning agents are concerned, if you can get the result you want using a paintbrush and compressed air, do that. Alcohol is normally pretty safe too. Organic solvents like gasoline will dissolve wax and this is not a good idea unless used very sparingly. Aliphatic hydrocarbons like CRC 2.26 (in a spray can) are normally pretty safe too.

Have a good look around the chassis. If it looks like it may have got wet at some stage you might consider removing the mains transformer, taking off its covers and giving it a long soak ( a few days) in one-part epoxy clear lacquer. NOT the water-based type but the type that cleans up with turps. Leave it a few days to dry, put the covers back on, wire-brush it and give it a fresh coat of black spray enamel. Let that dry and re-install it.

This should ensure that your transformer will last at least another 70 years and it also greatly reduces the possibility of a breakdown or leakage to ground. Where I come from a fault like this will result in annoyance tripping of the house electrical earth leakage breaker and, if you ignore it, a fire. But we have seriously dangerous voltages on our power outlets, you are somewhat safer where you are.

Remember that back in those days they didn't have the modern insulation materials we now have. What they did have was stuff that would absorb water, melt, carbonise and eventually catch fire. A modern epoxy lacquer will seal the transformer and this transformer is your safety barrier.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 8:23 pm 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
Thank you for the pics notime. It doesn’t look as daunting underneath as I imagined.


Rob, thanks for all the advice on cleaning and such. I goals for the weekend are to clean everything and build the DBT and order the books. I am looking at CRT testers on the web. Does anyone have any suggestions on what to get?


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Thu 22, 2018 10:22 pm 
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Joined: May Sun 07, 2017 11:35 am
Posts: 441
How about this??

viewtopic.php?f=3&t=331576

It will cost you a few cents on top of your existing tools and you now have a list of test results so you know what to expect

You'll probably use it once or twice ever - bit of a waste to buy a dedicated CRT tester unless you are going to do this for a living....


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Fri 23, 2018 1:32 am 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
well the testers are pretty cheap unless they are junk on ebay. I don't mind giving 20 or 30 dollars. Don't they sort of "fix" some problems with the CRT? I'm wondering that way outside my knowledge. Forgive any ignorant questions.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Fri 23, 2018 2:36 am 
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Joined: May Thu 14, 2015 4:15 pm
Posts: 1074
Location: Dallas, TX
I've got a B&K 465. Picked it up at a flea market for about $ 25 if I remember right. The tube data with it was updated in 1973. That happens to be about when the last of the tube TV were made. For color CRTs that have three guns you need to move a switch to test each one. Some later testers checked all three guns at once so they have three meters. Many CRT testers have a rejuvenate function and most of those could make the CRT worse. Back in the day when CRT were still being made rejuvenation was worth the gamble, not so much now.

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


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Fri 23, 2018 4:07 am 
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To be worthwhile any tube tester needs to be validated and to do this you need a range of old TVs that are working and a range of tubes.

There is no guarantee that any dedicated tube tester you buy is going to give you valid results. It can be pessimistic or optimistic depending on who fiddled with it last and the condition of the components. If you can find a range of working old TVs to verify it (as you did back in the day if you were a TV serviceman) then, and only then, can you be confident it's telling you the truth.

Back in the day, rejuvenation of a CRT was only done as a last resort, before you placed an order for a new tube (when you could still get them!) It is a kill-or-cure process. And the cure, if it worked at all, often didn't last more than a few weeks anyway. I would do it in the customer's premises so the old tube would last long enough for the replacement tube to arrive.

My little circuit, which you can easily and exactly replicate, will give you results with which you can have confidence, based on my validation tests.

Why spend money for something that may not do what you want and which you may end up only using once??


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Fri 23, 2018 2:07 pm 
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Joined: Feb Mon 19, 2018 11:33 pm
Posts: 53
Location: Lafayette Louisiana
Good point. It boils down to confidence. I need to nut up dive in and build the circuit. I have never done anything like this. Always wanted to learn electronics and have been so fearful of it. You'd think I was electrocuted in a past life. I'll build the circuit. I saw the diagram. Can I get everything from lowes or do I need to order from the web? We had a radio shack but it just closed down unfortunately.


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 Post subject: Re: 1953 Admiral Television help
PostPosted: Feb Fri 23, 2018 7:52 pm 
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Location: Dallas, TX
irob2345 wrote:
To be worthwhile any tube tester needs to be validated and to do this you need a range of old TVs that are working and a range of tubes.

There is no guarantee that any dedicated tube tester you buy is going to give you valid results. It can be pessimistic or optimistic depending on who fiddled with it last and the condition of the components.

Why spend money for something that may not do what you want and which you may end up only using once??

Maybe you have had some bad experiences with testers in the past. Any tester can be validated, repaired and re-calibrated using standard equipment. The tester circuits are basically the same ones you are promoting, measuring the cathode current (emission) under certain bias conditions.
I agree that if dandypanty only tests one CRT it probably wouldn't be worth buying a dedicated tester.

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


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