1949 Hallicrafters T-54 restoration part 1
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- Опубликовано: 8 сен 2024
- Let's start a new project. This time it is an electrostatic 7" Hallicrafters TV assembled on Feb 8th, 1949.
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Looking inside this set reminds me of opening the B&K 1077B Analyst.
Kind of reminiscent of an old scope. Varying frequency horizontal sweep to provide the time base, and disconnect the vertical oscillator and provide selectable attenuation or gain for the vertical (scope probe) input, and you have a simple, but heavy, 1-channel oscilloscope!
I’ve read that the T-54 HV transformers tend to fail after a few minutes of operation…moisture issues? Don’t recall.
I have a couple of Hallicrafters communication receivers in this cabinet (yes, the SX-42, SX-62, SX-101 and others resemble the T-54). A couple of them needed prybars to snap open. You can bend the spring tabs that “pinch the nipples” to ease some of the excessive grip.
I restored one of these several years ago. I had to bake out the HV coil with a light bulb for a few days before it would generate proper HV. Unfortunately my 7JP4 is rather weak and needs ~7.5V to create an acceptable picture. I'm really looking forward to this series, thanks! --N2GX
Mine came from a barn loft. I used a hose after collecting all the stickers. Let it bake in the sun and dry in the basement. It turned out like new with fresh paint, runs good too with a sharp picture.
Hey Bob this will be a lot of fun to watch, nice to see an old Ham Hallicrafters set with ch 1. which no longer exist. Always look forward to an evening with watching you. Been working on my Ham Galaxy V transceiver which is giving me lots of headaches. Love watching you. Learn new stuff all the time on your channel. Thanks for the efforts and great kindness in sharing
your one of my favorite channels. Be patiently waiting for the next videos. thanks Mike
I used to have a early run T-54 with metal tubes. the later version had mostly minature tubes.
Welcome to the boat anchors of television. Allison and myself have a older version on the bench. Allison did manage to find those 0.033 capacitors after looking over the schematic. While I was figuring out the touch up paint and getting a plan in my head for that unit. Take care stay warm and safe.
Yes, Gudeman caps are mostly high end sealed oil types, found in military sets. Actually, consumer grade Gudemans are rare!
Thanks for the info. I'll hang on to them.
Mastermilo has a video series where he restores a T-54, but that T-54 looked very different compared to the one in this video.
What a cool television set! I miss my collection but not the dust. Thank you for all your videos!
High voltage has a way of inviting dust to stick around, doesn't it.
I restored the exact same model a couple years ago.
I very much like the look of this TVSet. It looks like test equipment and is easy on bench space.
This is a neat little tv and will be an interesting restoration series to watch. I ran across one of these a long time ago in an eldery gentlemans garage along with a 58 Cadillac. It had a ton of stuff stacked on it against a wall. The pushbutton tuner was neat. Looks like a well built tv
That perforated cover is a Hallicrafter's tradition, it keeps all the heat in but, lets the dust pass through.
Octal based tubes have a maximum usable operating frequency of about 30 MHz due to the lead inductance between the tube elements and the base. To counter this problem, RCA came out with the Loctal base in about 1937. The 7 and 9 pin miniature based tubes have even lower lead inductance.
Electrostatic CRTs are more suited for oscilloscopes, where the deflecting plates can easily accommodate a wide frequency range. I guess they found their way into televisions in the 1940's due to CRT industry being set up for military and test equipment use. For TV use, magnetic defection is ideal, since sweep speed is constant plus, magnetic deflection is much more practical in CRTs with a high deflection angle (which short neck CRTs have).
Some of the older oscilloscopes have huge DC blocking caps for the deflection plates, as is needed for the really slow sweep speeds. Later, it was found that it was more practical to use a few hundred volts on the deflecting plates but, run the CRT cathode at -5000 volts.
They used them in early TVs for the lower cost. Motorola was the first below $200. The 3" pilot the first below $99
An early 60s Conar oscilloscope I got as a kid from a garage sale had a similar high negative voltage cathode arrangement, though only around -2000 volts with a 5UP1. To support that, however, the heater had to be run from a separate insulated winding on the power transformer. A power transformerless design like this Hallicrafters electrostatic TV couldn't do that.
@@SeekingTheLoveThatGodMeans7648 I'm not sure at what time running the cathode at a high negative voltage became the standard design choice for oscilloscopes. In the case of this Hallicrafters TV, it would probably be a simple case of reconfiguring the positive high voltage supply for a negative output voltage.
@@bandersentv Thanks Bob for confirming my assumption on electrostatic CRT usage. I assumed the military in WWII was using the electrostatic CRTs in radar displays and all types of indicators. So, with manufacturing already set up, the same CRTs could be manufactured with the P4 phosphor I would think quite easily.
@@billharris6886 Most radar actually used magnetic with rotary yokes or electostatic with polar deflection CRTs. Apparently the 7JP7 was developer for radar use, but I've never come across one. I see one just sold on ebay so they definitely do exist. I suspect they are rarer then the P4 or P1 versions.
25:40 I have those same husky screwdrivers. Came in a big pack, most have already evaporated.
11:30pm Sunday, -5.4 in Chicago suburbs.
-7 11:45pm where I'm at
I have one of those and also the wooden one. This metal one is missing an antenna input coil but I substituted a couple coils and I have them both restored and working.
I've got a 505 version (mahogany wood cabinet). After I got it I gathered the parts I planned to replace and found all the technical info I could. Mine is the later chassis version. I never seem to have the time to start the restoration. I've read about the HV fading many times when the sets warm up. One fix is to install a small fan to cool the HV cage. I also picked up a parts chassis, neither chassis had a cover on the HV cage. Also someone did a hack job enlarged the mask opening on mine. There is an article at the Phil's Old Radios website about his restoration of a 505.
Maybe that is why the HV cage top was removed.
Yes, probably
Bob, I have been curious about the 1940's Hallicrafters T-54 TV set, your video on the restoration of this set is interesting to watch and can hardly wait to see the next video. I was thinking of getting one of these TV's because of what it is (ie. has channel 1), but not too sure now if it would be worth having one, because of the amount of restoration needed.
Well every TV from the 40s is going to need a similar about of work
awesome
The cabinet looks similar to the sx62 receiver they produced.
It sure does. I bet they are the same
Someone should add this TV to the Hallicrafters article on Wikipedia. Quite a few postwar receivers are listed, but no TV. Perhaps list the Sams as reference.
They made a bunch of different models including full size consoles into the 1950s.
@@bandersentv I have (and restored) an 813 myself :D
Hot chassis! Use an ISO trans permanently.
Nah. It's fine. It's isolated from the cabinet. I could also install a polarized plug and put neutral to common.
oh holy crap I didnt know the cr70 put a dot on the screen!!!! I need to try mine!!! wow
That only works for electrostatic CRTs,, but it is pretty cool.
I may have blinked my eyes while watching your video Bob, but I didn't see whether the chassis was sitting on rubber feet or such to isolate it from the cabinet or not. I would think that's a given since it's a "hot" chassis? Could you confirm please?
Thanks for sharing a very interesting video :)
Phenolic shims separate the chassis from the mounting brackets under the chassis
Great video Bob, very interesting old set. I'll be watching this one closely. Let us know where you locate the specialized capacitors. This will be a very cool and unique set when you get it finished.
Well Bob, I was curious about the availability and cost of the 0.05uf 6,000 volt capacitors. Easy to find them in stock or long lead times by various sellers and they are about $40 (or more) each. Ouch!
But what type? They need to be plastic film and ideally axial leads. I see some from Bulgaria on eBay for only $20. Lol
@@bandersentv exactly what you need. (plastic film and axial leads!)
Does electrostatic picture tubes have (or need) ion trap magnets?
No, they don't but, yes, they would benefit from them. These were low end sets and it would be complicted (or maybe impossible) to implement so they don't bother
How many years was Hallicrafters in the television bussiness?
Looks like about 10 years. 1948 - 1958. web.archive.org/web/20200205185121/www.tvhistory.tv/1950-59-HALLICRAFTERS.htm
👍👍 I'd give you more thumbs up, but I only have two
Thank you. This set is a welcome relief after all the Predictas
Ok which ones the getter? The 1st metal ring or second metal ring?
Nether. It's the shiny splotch on the inside of the glass
oh ok so if the getter spot inside the glass isnt shiney then the tube has air with the milky look?@@bandersentv
@@zundfolge1432 Yes, exactly
How can old televisons be collectable" Those televisons can't be worth more then when they where brand new . I read years ago in the seventies (popu;ar mechanics magazine ) on what happened to channel 1 I always remembered that article
The original cost of these sets was quite expensive actually.
Anything that piques one's interest is collectible. I have been collecting old radios and TVs for over 50 years.
Old TV's are a tremendous teacher of electronic fundamentals giving lots of value. The history is very interesting to see how we got to today. When Bob's furnace or car has an electrical problem it's a pice of cake for him.
In 1948, the Hallicrafters T-54 was $169.50; in 2023 money would be $2,140. The ad claims this is, "an amazingly low cost."
Through a combination of inflation and collectable rarity and nostalgia and antiquity (and the need for substantial rebuilding at their age), now they are. I see cars of the vintage my parents bought that now are priced more than our house was (again inflation has been a large factor, as well as the other things).
@@abcsd1254 Doubtless it was at the time. It would be what, half a month of a middle class person's salary?
ok so 7jp4 tube
S 38 b