Mercury TV-220A restoration
 

A few weeks ago I was contact by forum member 'mrfixx' asking if I could get his old TV running. He said it was a Mercury TV which really got my head scratching.
Never heard of that brand before :scratch2: He provided a few pics and I started searching for any info. Maybe he'll chime in with the back story on how he came to own it.

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Well long story short, I had business up his way yesterday, and stopped by to check it out. Other than some scratches on top, it's in pretty darn good condition. There's a pull out phonograph below (78 rpm?) and it's got a 16" 16RP4 CRT. So I'm guessing around 1951 vintage.

Pulled all the knobs, undid the chassis bolts and pulled the chassis. I don't think this set was ever serviced.
Every screw and bolt for the back and chassis was present and don't see any evidence of replaced parts.

Here it is back at my place.
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That tuner struck me as odd right away. Eventually, I found some service info in Riders vol 6 and 8.
It looks like Mercury was only around a very short while and only made sets with this basic chassis which is also listed under S.M.A. I don;t know who S.M.A is, but I'm guessing they made it for Mercury.

Vol 6 contains several pages of theory, alignment info and several schematics none of which quite match. Vol 8 has a one page schematic that seems to match very well.
Here's a link: https://drive.google.com/file/d/0B37...ew?usp=sharing
Couldn't find anything from Sams.

Now I can see that the tuner is a continuous type using 6 variable inductors. It covers the VHF low, high and FM bands. Supposedly, it also cuts juice to the horizontal circuit while in the FM band. I'm curious to see that in operation :yes:
It seems to be frozen right now. Hopefully, some carefully cleaning and lubrication will take care of that.
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I did all I could with the 16RP4 CRT, but can barely coax any emissions out of it. Luckily, I have a spare 16KP4 aluminized version that should fit perfectly.

Because it's so pristine I figure I'll restuff all the caps. I have a few outstanding projects to wrap up, then hope to dive right into it :thmbsp:

Meanwhile, any info on Mercury or S.M.A. would be much appreciated.

Mercury was a record label, and judging by the decal it is probably the same Mercury.

TV was big into the mid 50's, and when that set was made two other record companies (RCA Victor, and CBS Columbia) were making phonos and TVs so they probably got in to TV as a sort of "me too" imitation of the big conglomerates.

I aquired this set from a friend of the family. My sister was going through their storage locker, saw this, and sent me a pic. I wanted it! So she delivered it here, and since I am VERY disabled, I asked for help getting it running again. While taking pictures the tv almost fell on me. As luck would have it, my wife was there to help get it off me. Cant wait to see it in operation... Fixx

Is the turntable missing? My guess would be most likely a 900 series V-M, though Webster Chicago is also a good possibility. Either way, in 1951 they almost definitely put a three-speed changer in it. A TV combo is only likely to have a 78-only changer if it also has channel 1.

Good eye! that winged head logo is a match!
https://en.m.wikipedia.org/wiki/Mercury_records

jr

I bought a Mercury TV here in Idaho. Mine is newer(21") Maybe 1953? I believe they're made in Los Angeles

Was that perhaps Pacific Mercury?
https://en.m.wikipedia.org/wiki/Pacific_Mercury

jr

possibly. I have not looked in a long time

The turntable is there. I recall it was very basic but there might have been a speed selector.

Interesting set of brochures linking to Mercury records in Chicago, not Pacific Mercury in Van Nuys.

http://www.ebay.com/itm/MERCURY-RADI...MAAOxycD9TWv5P

jr

I used to have a 12" round tube Mercury set. It used the same chassis as a Silvertone.

I've been researching early TV for decades and never even heard of a Mercury TV. Very interesting. One thing for sure, in the early postwar years everyone and anyone attempted to jump on the band-wagon and market a television set. A friend of mine gets a constant flow of vintage sets and I've seen the most unusual names on them through the years. If you made a complete list of them all it would be huge.

Very cool! Too bad I don't see this set pictured. Odd that they had so many models and so little info exists about them.

That canvas strap holding the jug on might be deteriorated enough to break easily. This has been the case with some split-chassis Philcos with canvas straps securing the CRT.

Oddly the same eBay vendor that listed the Mercury TV brochures also has some trade show pictures featuring S.M.A. , Chicago:

http://www.ebay.com/itm/TELEVISION-P...MAAOxyThVTX-ny

jr

There's another thread here about Mercury sets, seems Brando is seen with one in Streetcar, or maybe it's On the Waterfront? it's different model however.

http://videokarma.org/showthread.php...ghlight=brando

http://videokarma.org/attachment.php...0&d=1325413209

Not to worry - there's a steel band underneath the cloth.

I think I see this tuner down at the bottom.

That is impressive. Most guys just give their chassis "yellow" disease, unless it is a particularly rare and valuable set.

It is the same Mercury as the record company, they began by manufacturing radios, televisions, and phonographs, and in 1947 founded Mercury Records. And were purchased in 1961 by Philips of Holland. A beautiful early postwar set, and a very scarce set.

I got the set up on the workbench today. Looks like serial # is X4136. I wonder how many were made ?
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Super clean inside the HV cage. Interesting focus and centering magnet assembly. It is both a permanent and electromagnet.
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I pulled the 5U4 rectifier and tried a power up. I quickly discovered a blown fuse and replaced it.
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Success! Unloaded HV secondary is around 750 VAC.
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Encouraged, I decided to give it a brief try with the rectifier in while carefully monitoring the B+. Things looked good but after a coule power cycles, the 5U4 died. I then worked on the frozen tuner a while and was able to free it up. I popped in a new 5U4 and gave it another go. It held up and I was able to pick up some FM stations :)

I also removed the weak CRT and installed a 8XP4 bench CRT. I have to keep it at an awkward angle because the grounding strap makes contact with the HV button.
No luck - 0 HV. Still not bad for a first power up. I'll get to recapping next.

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Mercury Records produced the finest sounding recordings ever made, in
many people's opinions. The main reason was the exact polar pattern
vs. frequency curve of the microphones they used ... plus the extremely
low noise and high dynamic range (up to 140 dB!) of the tube used as
the microphone cathode follower. Google "Wilma Cozart".

I replaced the four corroded sand coated power resistors and recapped the horizontal circuits. I gave up on restuffing after the first two cardboard cap tubes crumbled.

There is a funky assortment of resistors like I've seen in other early 50s sets. Perhaps due to Korean war shortages plus the huge demand for TVs.
Also seeing some deviation from the schematic like this 39 ohm plus two 1M in parallel. The schematic shows a 47 ohm and single 1M. I figure it's best to stick with the values I find in the set.
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Did another power up and started hearing some arcing in the HV area. Some investigation revealed a splice in the HV lead and a dirty HV rectifier socket.

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Eventually, I also discovered the 1B3 had a crack in it. Not sure if it was always there or if the arcing caused it.
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With that sorted out, I finally got raster :)
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Swapped out a bunch of weak or shorted tubes and got better sound and contrast. Think I'll focus on the vertical circuits next.
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I replaced the electrolytic caps in the B+ supply and vertical output circuits. All four of the can electrolytics in this set have cardboard covers over them which I was able to remove with a little heat. Then, I cut them open and installed the new caps. Once I'm done, I'll pop the cardboard back on to hide them.
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Now I've got full height and good linearity. I also installed a new, longer HV lead so I can flip the test CRT around and avoid that grounding strap.
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I finished recapping the set and popped the original CRT back in. Since it had tested so poorly I wasn't surprised that the best I could get was a dim, out of focus image. I had to dim the lighting to take this photo. The brightness control has virtually no effect.
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Replacing it with a good 16RP4 made a very noticeable difference!
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Tweaking the controls improved the focus and brightness is most definitely much better. I do have some streaking though. I'll check the peaking coils and video amp circuit.
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That chassis looks similar to the RCA 630 set.

Starting to look pretty good!

Amazing what new caps can do. :D

Looks good! Nothing like seeing a set that was dormant for so many years come to life.

Here's a look inside the continuous tuner. They use a three position cam to skip the FM band and move it to the end so it goes 2-13 then FM. That also gives it a nice wide FM tuning range so it's not all bunched up.
Power to the flyback is also killed while in the FM band so the screen goes dark.
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I replaced a few more out of spec resistors, reinstalled the tuner and twiddled with the controls a bit more.
Picture is better, but still not quite happy. I'm getting sound at two points - very noticeable when tuning the FM band.

So I figure I'll go through the alignment procedure. It looks pretty standard with a 21.25 MHz sound and 25.75 MHz video IF.
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I managed to install a NOS cord by heating it up and mushing the ears over the rivets.
I don't have many of this type cord left. They used to be so common - never figured the supply would dry up :(
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Also getting ready to recoat the CRT with some Slip Plate.
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CRT turned out nicely - still working on the alignment...
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What's this slip plate stuff? :)

Basically aquadag spray paint. If dag is flaking off it is one of the presently made/available products to re-coat/replace old dag with.

I've been using this stuff to recoat, done three tubes with this can and it still feels nearly full.

Unlike Slip Plate. it makes a hard black coating that doesn't easily mar or rub off on your fingers.

It's quite conductive too, I measured the resistance from one side of a 14" tube to the other and it was about 2k.

You can get it on Amazon for about $16 if you have Amazon Prime.\

http://www.amazon.com/MG-Chemicals-C...uctive+coating

What sorts of symptoms would you notice if about 1/2 or 3/4 of of the dag coating were missing, even if all remaining dag were still grounded?

Dark patches on the screen from poor HV filtering and or noise on screen....Also rarely does a significant portion of the dag come off without "islands" forming, and the islands tend to arc to each other/other dag and grounds which may cause implosion....So far (knock on wood) I can't say I've seen a set with more than %10 (the most I'll tolerate before wanting to recoat) bad or lost dag. If dag damage ain't bad I eradicate dag islands and move on with my life.

Thanks Tom,

I love how the slip plate makes my CRT's look like new.
The stuff Eric linked to looks pretty nice also. Looks closer to factory.

Is this really a well documented phenomenon, the resulting in implosion part? Don't recall ever reading about that before. :scratch2: