Hallicrafters T-506 scored
 

I saw newhallone's post about an Admiral 20X122 for $30 up in Michigan. It's about 3 hrs away from me, but that's an awesome price so I contact the seller.

Someone beat me to it :grumpy: but... he has another set for sale. A Hallicrafters T-506. I grabbed a friend to keep me company and drove up to Grand Rapids, MI.
7 hours later, I'm finally back home :drool:

So here she is - pretty good shape. Just one knob missing - anyone have a spare ?
http://www.bobandersen.com/images/ha...t506/01-01.jpg

Needs a little refinishing, but nothing too bad.
http://www.bobandersen.com/images/ha...t506/01-02.jpg

Nice, original back. Except someone installed a 1/4" jack for an external speaker :mad: At least they did a clean job.
http://www.bobandersen.com/images/ha...t506/01-03.jpg http://www.bobandersen.com/images/ha...t506/01-04.jpg

Ugh, more oxidized cadmium plating I think :yuck:
The black knobs have gone all white with oxidation/mold too.
http://www.bobandersen.com/images/ha...t506/01-05.jpg

The chassis seems to be all original and unmolested other than that audio jack.
http://www.bobandersen.com/images/ha...t506/01-06.jpg http://www.bobandersen.com/images/ha...t506/01-07.jpg

I popped the CRT in another set. My streak of good 7JP4s continues :thmbsp:
http://www.bobandersen.com/images/ha...t506/01-08.jpg


Now for the icing on the cake. The seller has a bunch of old radios so I ask if he has any spare tubes for sale.
Yep, I got an 80 and 483 globe for my Sparton 931.
I just need one more 483 and I'm in business :banana:

http://www.bobandersen.com/images/ha...t506/01-09.jpg

I had no idea that Hallicrafters made TVs.

That white oxide crap on the brown knobs is easy to clean up - stop at the auto parts store and pick up some cleaner for plastic trim and convertible windows. late 40s/early 50s American Flyer train couplers form that white junk, too - that's where I learned to clean it up.

Cool. I knew posting that would help someone out.

Yew DAWG !! Ah HATE Yew...(grin) Seriously, GREAT score !! W/a good 7JP4 like that, way over half the battle's won, I would think...Can't wait to see it up 'n' runnin'...

Yep, they made TVs from 1948-1958

http://www.tvhistory.tv/1946-49-HALLICRAFTERS.htm
http://www.tvhistory.tv/1950-59-HALLICRAFTERS.htm

Thanks for the tip about cleaning the knobs.
Bob

I have three Hallis:

http://antiqueradio.org/halli505.htm
http://antiqueradio.org/hallit-67.htm
http://antiqueradio.org/HallicraftersT-54Television.htm

The 505 and T-54 have the same chassis as the 506, only different cabinets. The T-67 is a typical late 1940s 10-inch set, apart from the pushbutton tuner.

Phil

Even with that stuff, it's going to take a lot of elbow grease to get rid of it, and it will probably come back a time or two, though in lesser concentration. I got to the point where rubbing the crud down with the cleaner, then attacking it with a bristle brush in my Dremel was the only way I could cope with it.

Maybe that is one of the dreaded soy plastics that seem to keep breaking down, more or less, no matter what's done.

A couple of days ago, I heard an ocean scientist talking about modern plastic and how water creatures get sick from eating it. He noted that we have known how to make more degradable soy-based plastic since the 1930s.

"Damn straight," I said, "and I've got the rotting radio knobs in my workshop to prove it!" :)

Your knobs still have the original shape. As a last resort, if they continue to deteriorate, you could use one to make a model and then cast acrylic repros.

Phil

Thinking out loud here-Do you have access to one of those ultrasonic jewelry cleaning gizmotrons ? That MIGHT be what the doctor ordered... Again, just a thought...

That's great... double win with set and tubes! That's a nice H-C! That chassis sure looks easy to rebuild!

Older Motorola knobs are bad about that funky white film as well. You get them cleaned up real good with soapy water and a toothbrush... and a few months later, they need it again!

I wonder... after getting them clean real good, perhaps coating them with some clear spray enamel paint would preserve them. I would try on one of the rear knobs first and see how they look several months later.

With the right chemical cleaner, that stuff should stop forming eventually.

I cleaned up one of them using a toothbrush and lots of elbow grease. They're actually in really good condition under that white film.

That's what I'm hoping. That or a clear coat like Charlie suggested.

If you have a spare knob, try the clear coat. I'd be interested in the results, but I fear that the crap would form under it.

This isn't the type of crumbling, decaying mess that some plastics become. In my experience, the original plastic is just as strong as ever under that nasty waxy oxide.

I believe this stuff keeps exuding from the plastic. I have some radio knobs that do that and have a sickening stink like rancid butter or something. Don't think there's any permanent cure, just cleaning as necessary. And holding your nose.

I'd say closer to vomit :puke: I have a couple boxes with 100s of knobs in each. It's pretty nasty when I need to go searching in them.

Once I get them all cleaned up, I going to try some simple treatments like Novus #1 and furniture polish. I'm a little leary of using something with a solvent like lacquer has cause it might melt the plastic surface.

Might be worth experimenting with some of the nasty knobs in those boxes you mention... find some with the film and see how they react to different treatments.

Cool. Seems like you have (or are in the process of creating) a webpage for every set I've picked up lately :)

Anyone have a schematic for it ? I can only find the early version with 6SH7 tubes. This is the later chassis with 6AU6s.

Thanks!

Sure, great idea. I'll hold my nose and do some digging :D

I have the Riders and Sams for the 505/T-54. Both show the 6SH7 version.

If I'm remembering correctly, and these knobs are made of the same stuff, the material is breaking down internally, not being attacked by some evil mildew from the outside. That doesn't necessarily mean that sealing would be useless. Perhaps if you cleaned the knob and dried it really well, sealing it from moisture and oxygen would keep things stable for a long time.

People try all kinds of tricks to keep Predicta screen covers from breaking down. I polished mine with Novus #2 about 10 years ago, and it still looks the same. Not being a chemist, I have no idea whether these knobs are made of the same material.

My 505 project turned out fairly well, so I'm eager to redo the T-54, but there's a color set ahead of it in the queue.

Phil

I'm pretty sure nobody nearly 65 years ago ever imagined these rather slapdash, crude, feeble things would be coveted, prized possessions someday...Lots of people thought "Tell-A-Vision' was a passing fad then. And Hallicrafters really had more than they could say grace over, trying to meet demand for their radios...Altho they tried harder than most independents did to make TV a go...And they had a wealth of engineering background to draw upon, as well. And who could possibly have forseen in '46 that the mighty US consumer electronics industry had about 20, 25 years left to live, courtesy of a shattered, defeated nation, and an unremarkable invention made of sand & a couple wires ?

The US electronics industry is not in near as much trouble as many posters on this board seem to think. True, electronics manufacturing is worldwide now, but there is plenty going on in the US.

Texas Instruments is building a new IC fabrication plant in Dallas, IBM and the AMD Spinoff, Global Foundries have and are building IC fabrication plants in New York. Intel has many IC fabrication plants in the US. In addition to these other IC companies have fabrication plants here.

In addition to the above, many of the ICs used in consumer electronics today are designed in the US. Some of these are manufactured overseas, but the design work was done here.

The next time you purchase a consumer electronics item(or other item-such as an automobile) manufactured overseas, remember that a US designed/manufactured IC is probably included.

My guess is that Funky Knob Smell is caused by breakdown of urea in the plastic. I'm not a chemist...just play one on TV.

I will say that I've never noticed a weird smell from any plastics I've encountered with that white waxy residue. The smelly knobs might have a different internal chemistry with which I am not familiar.

I've noticed it mostly on late 40s knobs. It's not really a strong smell. I first noticed it when I opened a small box of knobs that had been sealed for many years.

I've been studying that 505 schematic and it does seem pretty close to my sets other than the 6SH7 tubes. Weird design. Especially the power supply and HV portions.

Here are links to a schematic I scanned from Most Often Needed Television Servicing Information 1948 edition.

http://www.bobandersen.com/images/ha...5%20sch-01.jpg
http://www.bobandersen.com/images/ha...5%20sch-02.jpg

Phil - any concern about the series wired 7JP4 filament?

Some folks install a little filament transformer to supply the CRT and wire a power resistor to take its place in the filament string. I did that for one of my series sets (don't recall which, offhand). I bought a transformer for my Pilot TV-37 but haven't put it in yet. It is a Triad F-13X.

Phil

Thanks Phil.

Sounds like a good idea - there's plenty of room to add one in.

Can you explain that crazy power supply? A 25Z6, 6X5 and a selenium rectifier!

Did you replace it with silicon? If you did, any change to the18 ohm resister in series with it?

Thanks again
Bob

In connection with that filament transformer for the CRT it would be a good idea to give the heater a soft start with something like a CL-90 inrush current limiter. This in series with the transformer primary has 120 ohms resistance at startup, and resistance drops gradually to about 7 ohms as the thermistor heats up, so the heater comes on gradually over part of a minute, helping preserve the life of a rare picture jug.

Yes, three rectifiers and seven electrolytics if I'm counting right. My National TV-7W has something similar, with a 25Z6 identified as a rectifier/voltage doubler and 6X5GT as a voltage tripler. Maybe something like that is going on here, although I haven't looked closely at either schematic.

A 6X5 rectifier is notorious in radio circles for developing a heater to cathode short. Various remedies are used, from installing a fuse to replacing it entirely. An Internet search may uncover some of those discussions. Perhaps the risk is negligible in a series string set, which has no power transformer to fry.

I'm a fan of the CL-90 ever since I put one in an RCA color set. Cheap and effective, just understand that it may get hot.

When I did my 505, I probably would have replaced the selenium rectifier with a 1N4007 diode and not changed anything else. Some people add more resistance in series with the new diode.

Phil

Thanks for the info guys. I think I have a few 6X5s in my stash - hopefully one is good.

I'll add some CL-90s to my shopping list :)

My one TV in my collection is a T-54.

After the recapping, the first image I got on it was....Austin Powers....:D

There's an Airline up on you know where that looks almost identical. I guess Airline rebranded the Hallicrafters.

http://thmb.inkfrog.com/thumbn/bagge...C06145.JPG=600

The Dachis Hallicrafters book says that Sears and Monkey Wards rebranded this set. Delco rings a faint bell, too.

Phil

I decided to take a whack at this set while I wait for an order of radio parts to arrive. Thanks to Phil's site, I have a good idea what's involved.
http://farm5.static.flickr.com/4050/...9084eeef_b.jpg

Plenty of nasty old caps to replace.
http://farm5.static.flickr.com/4043/...a52fe010_b.jpg

http://farm5.static.flickr.com/4051/...8f9e8ee6_b.jpg

I decided to try something new and restuff the paper caps. They come apart much easier than I expected - just a few seconds under a heat gun.
Then, I wrapped the new caps in some paper to make a tight fit.
Next, a little hot glue to hold them together. Finally, I reused the old wax plugs to reseal the end.
http://farm5.static.flickr.com/4032/...821bb86d5d.jpg http://farm5.static.flickr.com/4016/...f8969c95b8.jpg

Not too bad, but it's not much fun either. Now, I'll need to really keep track of which caps have been replaced!


Just one problem so far - it's the HV caps.

First, I have a 0.03 and a 0.005 here while the schematic calls for two 0.05 ?!? They look like the originals though (two in the upper-left) :scratch2: Can anyone confirm these values ?
http://farm5.static.flickr.com/4038/...c8443472_b.jpg

Second, I have a couple 0.00047 (AKA 470pF) for the horizontal. Can I use 0.001 instead ? That's the smallest ASC HV cap I've been able to find.

Nice job of restuffing! The wax they used to seal the ends seems to have a much higher melting point than the wax they dipped them in.

John

Thanks. Right, the sealing wax meted off right away and the end plugs were more or less intact. I crushed those end caps up and remelted the dust into the ends. I think it will be a lot easier to leaved them as intact as possible and just reflow the plugs over the new caps.

Nice job on the caps. Decades from now, someone is going to own your set and say "How could those old wax caps still be good? They test like new!" :)

Looking at the schematic for your Hallicrafters 506 6au6 type late chassis those two vert sweep coupling caps should be .03 at 6000v
However I am not certain that the late chassis schematic is the exact chassis you have.

Or somebody might look under the chassis and say "man, look at all those old wax-covered paper caps, I'm going to replace every one of them before I even think about turning this set on." :tears:

jr

Ps I have substituted .001s for .00047s for horiz output coupling an electrostatic set before with no problems.

I suppose I could leave a note inside the set ;)

Interesting. Any idea how the chassis run can be determined ?

I think I may have solved the little mystery with the vertical coupling caps. I discovered that the mounting band on the 0.005 has been cut and soldered back together. I bet it's a replacement (and a poor one at that).