These have been on my tv watchlist for a while-in that they are lightweight, easy to work on, and boast electrostatic deflection cicuits.

When one came up on ebay that was right in my hometown, I bid away, but when the bidding approached the $200 dollar range, I backed down and bid on another one. Well, it came today, and I snapped a few pictures of what I got:

I had requested it be packed carefully, and if this was any other set (ie not designed as a piece of luggage) it would have been smashed to pieces. I had requested that the seller open the back of the set and try to stuff some packing around the picture tube. What I got was a piece of foam stuck under the lid, protecting the face of the set. Other than being in a box that was too small, there was no other packing. With all that said, the tv appears to be in great shape.

I was very concerned about the picture tube-in every chassis picture I've ever seen, I never saw the tube supported by anything. Luckily, I now know the tube has a wooden mount inside the cabinet. With a little bit of dusting, the chassis cleaned up nicely. The picture tube must has been stored upright for the last 50 years, as the rubber crt face mount has melted all down the length of the tube. Stalagtites of the goo were hanging out of the back of the set when I got it. The picture tube itself looked like a guttered candle. With a little patience, this all came off with a bit of cleaner.

Looking under the chassis, I can only see that one cap has been replaced. The tubes are all RCA or Motorola, except for a cheasy "long life" unbranded tube. Looks like this set saw little service before getting put aside. Manufacturing date is May 24, 1949. Personally, I can't wait to get into this one. I expected this set to be of pretty cheap construction, given its low selling price, but the quality is really decent. No wonder Motorola sold so many of these.

edit:
Don't see the pictures? Well, I didn't post any as I am having issues with my SD card reader. We'll see if I can amend that later today...

Finally! Let's see if I can attach pictures...

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Love the electrostatic sets! Keep us posted!

Congratulations!! I am fortunate to have two, both with good CRT's. They also are the same chassis series, TS-4J. There are variations in the chassis through the production life, with many circuit changes. Best of luck on the restoration!!
Kevin

Oh, forgot to mention that mine are VT-71's.

Fun sets. Here are my restoration notes for what they're worth. That was several years ago. I might do some things differently now.

http://antiqueradio.org/motvt73.htm

Sold mine at a swap meet a few years ago, so now all that's left of it is a short video of a Scrubbing Bubbles commercial. We still have three other 7-inch sets in the house, though.

Phil

Cool :thmbsp:
I'm glad it survived. Few sellers know how to properly pack a TV.

I think few sellers know how to nor care to pack anything properly.

Thanks for all the comments! I forgot to mention the huge gash in the lid of the case-looks like it was done by a circular saw. Maybe someone used this as a sawhorse. I still can't believe the crt was as "carefully packed" as I requested. I just went back and looked at the old email I sent and I can't see how they would mix that up as they did. I remember when I opened the lid and saw that bit of foam protecting nothing, all I could sarcastically think was "Wow, thanks! My cup runneth over!"


My plan here is to build a ballast on a heatsink like Phil details in his website. It may not look stock, but I would feel much better knowing the failure-prone ballast is out of the picture. Even on a set with apparently so few hours on it, the ballast cage is still pretty toasty looking. I also plan to replace most of the components on this set, as I plan to watch it quite a bit, and on a set this simple I'm sure that when one component fails, the whole set quits. Now, I just need to find a SAMS....

You probably have the TS-4J chassis? Here's the early version. I have the other pages too - parts list, voltage readings, alignment instructions too if you're interested.

TS-4J Early page part 1 (http://www.bobandersen.com/images/VT71/TS-4J%20Late-1.jpg)
TS-4J Early page part 2 (http://www.bobandersen.com/images/VT71/TS-4J%20Late-2.jpg)

Those came from a Wallace Telaide which has ledger size pages so I had to split it into two scans. Hope you can read it.

As for the ballast - I sent you a PM with info on where you can get a NOS Amperite ballast tube.

Bob

Banderson-thanks for the tip! If you can get the time, I'd like to see the parts list as well. This is a TS-4J chassis, but I'm sure there will be some differences.

Here are all my scans (http://www.bobandersen.com/images/VT71/)

Great looking set! I love these little Motorolas.

There are two variations of the TS-4J chassis - Early and Late. An easy way to tell them apart is to look at the Contrast control. The 'Early' just has wires. The 'Late' has some caps and resistors soldered to the pot. I have schematics for both.

Banderson, thanks for the link to your scans! That makes things much easier for me. FWIW, my chassis is a late version.


Well, time for a little update:

I started recapping early this week, and just today felt I had done enough to try to power it up. At this point, I had replaced all of the paper caps, the HV tubulars, and the lytics. I was rewarded with a fine picture! After a few adjustments, I was very happy with the result-the crt is nice and bright, indicating its low use.

After running for about thirty minutes, I could see some vertical issues, from loss of sync to some shrinking, but nothing serious enough that readjustment wouldn't bring back the picture. Audio was a little quiet, so I began measuring B+ and saw it was about thirty volts too low. My concern went to the selenium rectifiers, which I planned to remove anyway.

I dropped in new diodes, and wired each of them in with a 50 ohm resistor to create the appropriate voltage drop of the old seleniums. At the next powerup, poof! A little puff of smoke, and I knew the ballast was toast. As I suspected, the section of the ballast that forms a 200 ohm choke, which meets the diode's output, was what snapped open.

Checking my work, the install was correct (proper diode polarity, wiring in it's proper place, no shorts) but maybe the new diode/resistor setup wasn't dropping enough for that poor ballast. Oh well. I did snap get some screen shots, so that will have to satisfy me for now, until I can restore power. I'll post those pictures sometime later today.

Congrats on a very neat set.

These type of tv's are kind of exotic for me, I don't think I've ever seen one like it. Would be quite the adventure to restore one.

Kudos on getting it running and sorry it was short lived :(
Those old metal ballast tubes are prone to burn out. Did you get a glass ballast tube? They are much more reliable and provide a regulation effect when the set powers up.

I put a pair 1N5408's with no resistors in mine and had no problems with the HV. But it has developed a slow vertical roll after 10 or 15 minutes. Very annoying!
Terry

I used 1N4007 in 3 of my sets without resistors. All of them work fine and B+/B++ are right on.

That being said, it is generally a good idea to use a dropping resistor and will cut the current through the ballast a bit.

I used 1n4006 diodes. I was all out of the '07s, but I should think the ones I used are close enough.

The ballast I have is one of the crummy old metal cage ones. I opened it up, and the wire is strung over mica sheets, where it is periodically tacked down to the mica with blobs of ceramic cement. Well, age and transport have knocked those glued down portions free, so the wire was just getting shaken quite a bit, which probably also weakened things.

Some screen shots. Sorry about the lack of focus, that combined with the wrong shutter speed really doesn't do the 7GP4 justice.

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Nice :thmbsp:
MST3K with Joel :D

Okay, I have it running again! I built ballast with Dale 25W resistors per Phil Nelson's site, and that did the trick. I'll probably get a more stock-looking glass ballast at some point.

I started replacing resistors in the vertical section, and while the shrinking problem has disappeared, the vertical hold is still very touchy. I hope to have this corrected before calling it a day with this one.

It is running so well that I even brought it into work to show off (it's the weekend, so we really haven't anything else to do) and it ran like crap of course. Between the server racks and the fluorescent lights, you could just make out the picture in a hail of static and herringbone. The set ran like it had a sound misalignment, too. I get it home and it runs fine as ever. I'm sure everyone at my job just thinks I'm more insane than ever, but what else is new?

hail of static and herringbone
I imagine many 1940s TVs would have the same response there. They were designed to be sensitive enough to receive weak stations. The RF environment they lived in was a lot cleaner than many places you'll find today.

Re the old ballast going poof, it's not unusual for marginal components to give up the ghost when they get the right voltage for the first time in decades. If you try the set regularly while you're replacing things, you can notice gradual improvements -- and sometimes new problems. The problems were there all along, you just didn't notice them while distracted by bigger issues.

These Motorolas are lots of fun. Enjoy!

Phil

I have thought of for the fun of it hooking a 5 or 10H choke in place of that resistor in the ballast tube. Would probably jack-up the B+ a bit and make it a little cleaner. Seems pretty clean to start with (not much hum at all) Has any one got a copy of this? http://cgi.ebay.com/ORIGINAL-Motorola-TV-VT71-Operating-Instructions-VT-71_W0QQitemZ360194958856QQcmdZViewItemQQptZLH_Defa ultDomain_0?hash=item53dd4ae608
Looks Kewl? Nice table too!
Terry

I've got the set pretty well dialed in now-I just have these interference lines scrolling across the screen. Can anyone speculate as to their source? This is a screenshot from a DVD player feeding the tv through an RF modulator. But even without the modulator signal, the set still has these lines:

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I'v worked through the resistors, and replaced about a dozen marginal ones, mostly in the vertical circuit. I've had it running for about two hours now, and it has not needed many adjustments, just a little fiddling with the vertical hold during warmup, and that was pretty much it. If this continues, I'll be pretty satisfied. Does anyone have a recommendation for a gasket replacement? I know there is a company that produces them, but they are sold out. I am more concerned with stabilizing the crt rather than aesthetics.

Do you have the metal flyback, CRT and tube shields in place?

All shields appear to be in place, in addition to the crt and flyback shields, I have these tubes shielded:

12sn7 clipper, AFC
6ag5 RF amp
6ag5 1st IF

I noticed that I can use the fine tuning to somewhat eliminate these lines, but that's all I've tried thus far.

I've got the set pretty well dialed in now-I just have these interference lines scrolling across the screen. Can anyone speculate as to their source? This is a screenshot from a DVD player feeding the tv through an RF modulator. But even without the modulator signal, the set still has these lines:

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Well, there's two sets of lines showing. Do you mean the white diagonal lines? That looks like vertical retrace. Do they go away if you turn down the brighness? Then there's dark bars slanting in the opposite direction. That looks like RF (from a computer power supply maybe?). Bill(oc)

The white lines are vertical retraces, I don't think these suitcase sets have vertical blanking, so they are pretty apparent.

If you set the contrast real high and play with the brightness you can just about eliminate them.

You can also try this mod: Possible cure for retrace lines on Motorola VT-71, VT-73 (http://antiqueradios.com/forums/viewtopic.php?t=12044)