Motorola VT-71 restoration (TS-4J chassis, Blonde cabinet)
 

Yes, I'm restoring yet another Motorola 7" set :D This is actually one of the first sets I picked up, but it was really chewed up so I left it on the back burner. The recent acquisition of some nice Amperite ballast tubes got me thinking about so I hauled it out. Also I figure I might as well finish it off while the TS-4 schematic is fresh in my brain.

Here it is as I got it. The cabinet isn't too bad, but the insides :tears: The CRT base was ripped off as was the CRT socket. Seems that someone decided to hard wire the CRT to the case. Maybe the old socket developed shorts?

I've already removed the CRT
http://www.bobandersen.com/images/VT...onde/01-01.jpg http://www.bobandersen.com/images/VT...onde/01-02.jpg http://www.bobandersen.com/images/VT...onde/01-04.jpg http://www.bobandersen.com/images/VT...onde/01-07.jpg

Also one of the tuning slugs is broken off and a HV pot is frozen. Plenty of ugly old repairs too with big solder globs on the replacement parts.
http://www.bobandersen.com/images/VT...onde/01-05.jpg


Finally, no tubes except the HV rectifier (that should have tipped me off to replace it!)
http://www.bobandersen.com/images/VT...onde/01-03.jpg

Oddly, the original mask is almost good enough to still use.
http://www.bobandersen.com/images/VT...onde/01-08.jpg

Re-stuffing electrolytics
 

Since the 3 electrolytics have cardboard covers, I decided to re-stuff by cutting them open near the base.
http://www.bobandersen.com/images/VT...onde/02-01.jpg

First, I had to remove the cardboard covers. Seems simple enough, but one of them was really, really stubborn. I ended up cooking it in the over @ 300F for 10 minutes to loosen up all that tar!
Next, I cut them open with a Dremel and pulled out the goo.
http://www.bobandersen.com/images/VT...onde/02-02.jpg

I was surprised to discover one had already been replaced with a pretty bad match! 30/15/40 isn't exactly 100/60/20 :no:
http://www.bobandersen.com/images/VT...onde/02-03.jpg

Here they are remounted. I'll glue the covers back on once the set is working properly.
http://www.bobandersen.com/images/VT...onde/02-04.jpg

Bravo Bob, another one well done (almost):).

Replacing bad components
 

Next, I tackled that frozen HV pot. I cut a slot in the plastic extender to finally free up the inner shaft. Maybe contact cleaner or age melted the plastic ?
http://www.bobandersen.com/images/VT...onde/03-01.jpg

I discovered a bad coil in the video amp and had to re-solder one end.
http://www.bobandersen.com/images/VT...onde/03-02.jpg

I put a new base on the CRT and replaced the socket. Quite a challenge for me.
http://www.bobandersen.com/images/VT...onde/03-04.jpg http://www.bobandersen.com/images/VT...onde/03-05.jpg http://www.bobandersen.com/images/VT...onde/03-12.jpg http://www.bobandersen.com/images/VT...onde/03-06.jpg

Next, I replaced all the wax caps, some mica (I tested them) and out of tolerance resistors (lots of them!)
http://www.bobandersen.com/images/VT...onde/03-03.jpg

I replaced all the missing tubes, did some final check, and slowly powered it up.
Nothin' :grumpy:
http://www.bobandersen.com/images/VT...onde/03-07.jpg

So, I start testing voltages at various test points - B++, B+ etc. It all checks out. Grrr.

Must be a bad tube or two - right? So I swap out all the tubes from a working set and, viola, audio on channel 6! That one low power OTA station in Chicago broadcasting light jazz.

Which tube was bad?
None of them! I had been referring to a tube placement diagram for the TS-18 chassis instead of the TS-4 chassis :stupid:
I really shouldn't work on so many projects at the same time!
http://www.bobandersen.com/images/VT...onde/03-11.jpg


Still no HV though. I pull the HV cover, turn off all the lights and see a ghostly blue glow coming from the 1B3. I pull it and it's a dud.
That was the only original tube left aside from the CRT.
The only replacements I have is a 1B3/1G3 which is a bit shorter so I need to reposition the feedback coil.
It should be 3/4" from the top of the base.
http://www.bobandersen.com/images/VT...onde/03-08.jpg http://www.bobandersen.com/images/VT...onde/03-09.jpg

Bam! I've got a working set :banana:. The vertical and horizonal sync are touchy, but I can work on that.
http://www.bobandersen.com/images/VT...onde/03-10.jpg

Here's a short video clip of it playing.

Next up, tweaking and restoring the cabinet.

Thanks Mark :wave:
There's a limit of 18 or so images (and smileys count!) in each post so I broke this one into sections. You caught me mid post :D

Thanks, Phil
I dunno about fast. It was about 4 weeks start to finish and I had all the parts on hand.

I have 17 more sets to restore, so your jobs will have to wait :D

P.S. I'm using lacquer on this cabinet. I think I've finally gotten the hang of it.
Kinda makes me want to strip and refinish the mahogany Motorola I use polyurethane on a while back :scratch2:

Thanks!
I've done about 1/4 of my TS-18 chassis from that smashed bakelite set. It's a real mess compared to this set so I used the parts I had ordered for it on this one instead.

Still, I expect to get them all running one day.

I'd really love to get all my sets running at the same time, on the same program and take a photo, but I think that'd take more juice than my place is wired for :)

Yeah, I was quite surprised too - hard as a rock and fragile though.

I've begun work on restoring the rest of the set.

Here's the original cabinet with the faceplate and control area removed.
http://www.bobandersen.com/images/VT...onde/04-01.jpg

I stripped it with CitriStrip and Mineral Spirits. Lightly sanded it, masked off the center portion and stained the rest with "Golden Pecan". I think it's a pretty good match to the original. Once it's dry, I'll used a few coats of gloss lacquer.

http://www.bobandersen.com/images/VT...onde/04-02.jpg

The original CRT mask is just too crusty and crunchy to use. So I grabbed one of the last reproduction masks from renovatedradios.com
Apparently the mold broke, but he still has a master molded in hard plastic. You can email a request and when he's received enough, he'll do another run.

http://www.bobandersen.com/images/VT...onde/04-03.jpg

I repaired a small tear in the speaker cone using this simple technique

http://www.bobandersen.com/images/VT...onde/04-04.jpg

Knobs, knobs knobs! I have 3 Motorola 7" sets that need complete sets of knobs. Mahogany, Blonde, Bakelite. Here's the knobs I have.

http://www.bobandersen.com/images/VT...onde/04-05.jpg

Here's my guestimation

Far-left is from a Motorola 9VT1 like this one

The center group of brownish knobs is for the mahogany and blonde. Not sure about the darker/lighter brown or the circular inset color.

Swirled, tan smaller knobs - no idea!

Finally, my lone golden knob for the bakelite set courtesy of Zenithfan1 (thanks Mark!)

If anyone can verify which knobs go with which set, I'd be very grateful. I'm also open to trading. All I need is 3 complete sets.

Here's what various combinations look like on this set. That's my restored photo finish on the control area. Took for freakin' ever to get it right. It's still not perfect, but I've spent way more time than I ever expected on it.
I wonder why Motorola use a photo finish for the front on the blonde sets? Maybe a rare wood was used? The Mahogany set is veneer all round.

http://www.bobandersen.com/images/VT...onde/04-06.jpg http://www.bobandersen.com/images/VT...onde/04-07.jpg http://www.bobandersen.com/images/VT...onde/04-08.jpg

Finally, I'm going to try making some custom decals for this set. It's similar to the repro decals sets that are out there in gold lettering, but this set needs brown lettering. Also channels 1,2,3-4,5-6,7,8-9,10,11,12-13.

The idea is that you print onto this special pape and, spray a few coast of clear, gloss enamel over it. Once it's dry, you can float the paper in water to release the decal like normal.
I hope it works out well, I have a few other sets that could use new decals.

http://www.bobandersen.com/images/VT...onde/04-09.jpg

I've also tuned up the set a bit and it's playing better. Here it is playing the opening to "Danger UXB" one of my favorite series :D

and another of "The Prisoner" opening

It's playing from a DVD player fed into a Blonder Tongue modulator set to channel 3 located about 30 ft away for a signal source.

My DVD froze for a moment in that 2nd video which caused the set to lose horizontal hold for a moment. After it locked again, the whole picture had shifted over an inch or so to the right.
Gotta love analog :thmbsp:

I forgot to mention that I put on a new set of rubber feet from Antique Electronic Supply. They are a perfect match for the originals.

http://www.bobandersen.com/images/VT...onde/04-11.jpg http://www.bobandersen.com/images/VT...onde/04-10.jpg

Interesting...
I found a bunch of knobs in this style at a radio show recently. I figured they couldn't all be from Motorola TVs. They do fit well though.

I'm glad you like my style.
Here's another exciting installment!

I managed to salvage the vertical center HV pot extender with a little epoxy cement and it's usable again.
http://www.bobandersen.com/images/VT...onde/05-01.jpg

The cardboard sleeve from the cap I roasted in the oven didn't survive the experience. So, I fabricated a replica using a toilet paper roll and glue.
I then spray them all with a little flat black paint - they look a lot darker in person.
I considered masking off that corner of the chassis and touching up the black paint, but decided it wasn't worth it.
http://www.bobandersen.com/images/VT...onde/05-02.jpg http://www.bobandersen.com/images/VT...onde/05-03.jpg

Next, I cleaned up that copper plating a bit.
http://www.bobandersen.com/images/VT...onde/05-04.jpg

I also replaced all 10 missing HV cage screws. Every set I have seems to be missing at least half it's screws!
http://www.bobandersen.com/images/VT...onde/05-05.jpg

Here she is all cleaned up :)
http://www.bobandersen.com/images/VT...onde/05-06.jpg

Next, I tackled the plastic faceplate with some Novus #2
http://www.bobandersen.com/images/VT...onde/05-08.jpg

Good as new!
http://www.bobandersen.com/images/VT...onde/05-09.jpg

This set is missing the bottom pan and the rear cover. Here's they are from another set. The bottom tray should be easy to fabricate with some sheet aluminum. I'm not sure about the steel rear cover other than using a piece of sheet steel and giving my drill press a real workout.
Any ideas?
http://www.bobandersen.com/images/VT...onde/05-10.jpg http://www.bobandersen.com/images/VT...onde/05-11.jpg

Finally, I tried to make some decals. I've attached the image file I created.
I printed that out onto some special decal paper and sprayed it with several coats of clear gloss acrylic as indicated. Looking good so far.
http://www.bobandersen.com/images/VT...onde/05-13.jpg

Ugh, I accidentally ordered the wrong decal paper :tears: Opaque white backing instead of clear.

On the bright side, it seems to work fine on my scrap sample.
http://www.bobandersen.com/images/VT...onde/05-14.jpg

Here's a preview of the set while I wait for the proper decal paper to arrive. I still have a little work to do on the cabinet. Touch up the top front finish, apply the decals and give it a couple coats of lacquer. Also the CRT isn't firmly seated yet.
http://www.bobandersen.com/images/VT...onde/05-15.JPG

I got the proper clear decal paper and it works great! I think being able to create my own decals is going to come in real handy.
I can't print the common "metallic gold" color, but a lot of reproductions for those are already available.
http://www.bobandersen.com/images/VT...onde/06-02.jpg


Finally, it's lacquer time !
http://www.bobandersen.com/images/VT...onde/06-01.jpg

I have some upcoming projects that will require a real fine, high quality lacquer finish so I'm going to try out this hand rubbing process.
Basically, you use sandpaper, steel wool, pumice and rottenstone to buff the heck out of that lacquer.
Has anyone tried this technique before?

I used this place
Inkjet clear

Well, I did it again... I misplaced the schematic of my TS-4J and I want to finish the vertical circuit before I put it back in it's case (been freaking customers out with it naked in the shop). If anyone can scan the vertical I would really appreciate the help.
Oh, it is OK to ridicule me for losing the schematic... again!

TS-4J early or late ?

October 2, 1948. If there is more info please let me know and I will post it.
Thanks!

An easy way to tell is from the Contrast control. The early version just has one end grounded. The late version has a few capacitors and resistors attached to all 3 legs of that control.

Contrast control only has two wires.
Thanks!

Here you go.

TS-4J Early page part 1
TS-4J Early page part 2

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.

Bob

Many thanks!!

My 2cents worth (or less)

I have a bakelite and a wood 9" with the type of knob shown in picture 1. Perhaps these sets are not correct? :scratch2:

I have seen the tan swirled knobs on the leatherette-covered "portable" (VT-73) version... picture 2

I have also seen the tan knobs on a blonde set. (looked good IMHO)

I have a Black bakelite 7" with the gold knobs... picture 3

jr

The knobs on my 9VT1 are exactly like the ones in your photo 1. The clear outer channel indicator part of the knob somehow seems newer than the rest of the knobs. Maybe it was just better plastic.

John

Thanks for the info. I've never seen those stylized "M" knobs before- very cool.

Those gold knobs look awesome on the bakelite set. I'm restoring one of those as well and only have the Volume knob so far.

I've got a VT-73 too with a complete set of knobs.

I think the tan knobs look great on the blonde and I'm leaning towards those even though my set came with a couple of the darker brown knobs.

Finishing supplies
 

My hand-rubbed lacquer supplies arrived today :)
I ordered these just before I read John's post about micro-mesh. That product seems promising (and less messy) so I think I'll give it a try on the next project.

http://www.bobandersen.com/images/VT...onde/07-01.jpg

My stupid printer ran out of color ink and I spent a few weeks finding a reasonable priced "refilled" cartridge. Here are the dark brown decals applied to the control area. This system works quite well.

Now I'm working on burying the decals in a few layers of lacquer. Then, I can finally start working on the hand rubbed finish!

http://www.bobandersen.com/images/VT...onde/08-01.jpg

Looking good! John

Here's a long overdue conclusion to this project!

The set was suffering from visible retrace lines so I tried out this modification I had to tinker with the resistor value to maintain vertical stability. 47K worked out well.
http://farm5.static.flickr.com/4143/...d94fcaee_b.jpg

That eliminated the retrace lines, but now I have random bright streaks in the picture. This was due to positive spikes in the retrace suppression signal.
http://farm5.static.flickr.com/4120/...13e4c230_b.jpg

http://farm5.static.flickr.com/4076/...2362c302_b.jpg

I added a clamping 1N4007 diode across the 47K resistor and the signal is a lot cleaner now.
http://farm5.static.flickr.com/4101/...e2db9926_b.jpg

So is the picture :)
http://farm5.static.flickr.com/4138/...c83f319a_b.jpg

Here's the circuit I used.
http://farm5.static.flickr.com/4076/...8bcfa855_b.jpg

I'm finally calling this project done :banana:

I made some reproduction high voltage warning decals for this and another set using white backed water slide decals.
http://farm5.static.flickr.com/4136/...f3511d2e_b.jpg

Time to put it all together.
http://farm5.static.flickr.com/4139/...fdef2f04_b.jpg

Here's the original back. I'd love to get a couple more of these for my other sets :yes:
http://farm5.static.flickr.com/4142/...814dfe6b_b.jpg

Here's the front. My restored / veneered photo finish is too orangy, but I can live with it. Someday I may give it another try. I've heard bamboo veneer is a good match.
http://farm5.static.flickr.com/4099/...5bf514c9_b.jpg

I had a heck of a time getting the reproduction mask to line up properly. The upper-right is still off a bit.
http://farm5.static.flickr.com/4093/...42085c16_b.jpg

There are a couple flecks on the screen and a burn hole near the bottom. Not too bad considering the base had been ripped off this CRT!
http://farm5.static.flickr.com/4139/...74e15176_b.jpg

very very nice work. great finish.

:thmbsp:

Orange smorange! That finish looks great as it is! Great picture too! Looks great with the retrace mod, no annoying lines!:D
Now here's another exclamation point just because. !

Very, very nice. I have the more common mahogany version and I hope to start on it soon. I have most of the parts and like you wish I had another back. I should have one soon...

I just touched up the original finish on my VT-71 (because it wasn't really too bad to begin with) but it doesn't look nearly as nice. And I don't have a have back for either of my VT71s. I've come to the conclusion that they must have made loads of these sets, they're so common compared to other 1940s sets, but somehow the fine tuning knobs and backs still seem to be quite rare.

And I have yet to get my 7JP4 all the way into my reproduction mask, every time I get it jammed all the way in there the picture winds up being a little crooked, then I go to turn it and it comes out slightly again. Anyway, the picture on that set looks great.

Thanks for all the kind words guys!

If I had it to do over again, I'd try to touch up the photo finish. The rest of the cabinet is worth refinishing I think though. The veneer is incredible looking - it really shimmers in the light. I asked around some veneer suppliers and the consensus was that it's blonde mahogany of some sort.

I bet most of the fine tuning knobs fell off. There's not much holding them on and they see a lot of action.

Maybe backs were removed for better ventilation ? The cabinet gets really hot above that ballast tube. I left the old asbestos in place to protect the wood. It should be easy to reproduce a back given some perforated sheet metal and a brake to make the 3/4" lip. Not that the lip is really necessary.


I had exactly the same experience with the mask in two sets !

Awesome man, that's a cool little TV :)

Thanks!

That's a great finish and a cool little TV. I'd love to find one like that to restore.

Question: I see the decal material you used was listed as "wood decals." Wonder how that material differs from the stuff that I use to make the gold ones?

It definitely looks like mahogany. I was reading that mahogany was originally finished like that, with it's natural colors. Over time it takes on the reddish brown color. People liked that color but didn't want to wait forever for it to develop so furniture makers started using stains to produce the aged look that everyone liked.

How quickly it turns color might depend on the type of finish. I used linseed oil on some mulberry wood and it develops almost overnight. But with shellac, it seems to retain a lighter color longer.

It'll be interesting to see how yours ages. It looks really great and must really have beautiful depth considering that it shows up well in the photos!

John

Wonderful job, as usual. I like the photo with everything laid out for reassembly. At that point, you can imagine yourself back in the factory, ready to put together a brand new 1948 TV.

Phil Nelson