Very early Motorola VT71 scored
 

I just picked up this set tonight. It's a Motorola VT71 with what I believe is the very first run of the chassis TS-4.
It has a 7F8 osc/mixer and two large metal 0.3 mfd @ 6000 volt caps mounted on the chassis. It also has channel #1 :banana:

Overall it's in quite good condition. The bottom cover is there with all the metal caps over the adjustment holes. It has the metal back, all the knobs, plastic faceplate is in very good shape. The only problems are a few veneer chips and the usual melted CRT mask. I actually had that large veneer chip in my hand when I picked up the set, but can't find it now :( Hopefully, it will turn up.
http://farm7.static.flickr.com/6029/...a8a7ec50_z.jpg http://farm7.static.flickr.com/6009/...c3fe4bd7_z.jpg http://farm7.static.flickr.com/6129/...6a4a6bd7_z.jpg http://farm7.static.flickr.com/6138/...fd12ded5_z.jpg http://farm7.static.flickr.com/6027/...56ac4393_z.jpg


Looks like it was at a garage sale and everyone passed on it.
The masking tape is really stuck on there good. Does anyone have any tricks for getting it off without damaging the finish ?
http://farm7.static.flickr.com/6005/...7a3a7344_z.jpg

Could this really be the 2,425th VT71 to roll of the line ?
http://farm7.static.flickr.com/6125/...e7d01c1a_z.jpg

The channel selector on these sets only has 8 positions.

You always get 1, 2 and 7.

The dealer would configure the other five (3/4, 5/6, 8/9, 10/11, 12/13) for your area.
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Here's a peek at the inside.

http://farm7.static.flickr.com/6130/...e6f98082_z.jpg

I really hope these are originals and not an ugly repair job.
http://farm7.static.flickr.com/6150/...995e4e8d_z.jpg

There's the 7F8 up towards the front. Later sets used a 12AT7.
http://farm7.static.flickr.com/6006/...868a6c59_z.jpg


Ah, those caps do appear on the tube chart so I bet they are original.
Weird. The earliest schematic I could dig up is the the TS-4B and it doesn't have these.
http://farm7.static.flickr.com/6145/...69176a04_z.jpg

That's all for now. I'll try to find time tomorrow to pop the chassis out and test the 7JP4.

Very nice. Both of my VT-71s are TS-4Ds, I think, and both have channel 1 and no fine-tuning control.

Cool. I didn't realize they had so many revisions with channel 1 and no fine tuning. The oldest I have is a TS-4H with fine tuning.

I just noticed the hum adjustment in the bottom cover. That's something else I don't see on the TS-4B schematic :scratch2:

Wow! I've never seen such a primative version of that chassis before.

Aw nuts, I checked in the Riders index and this chassis appears to be covered in volume 1 which I don't have :(

I found a scanned copy of Riders vol1 TS-4 chassis at the ETF. It appears that this is the TS-4 "late" version which uses a 6AL5 and 6SQ7 in the audio circuit. The TS-4 "early" uses a 6S8GT.
I was hoping it was the very first version, but it's still pretty darn early :yes:

Nice find, Early and unique and hope a good crt sweetens the deal.
Wow! the crt is connected using individual wires with sockets pushed on the pins of the crt base.

Nice little Motorola, shame we don't have early sets like these where I live.

I find turpentine useful for softening the adhesive on masking tape so that it can be removed. It doesn't harm most finishes but it would be wise to check first.

Seems like SOMEBODY was making "replacement" masks for these-I THINK I've seen 'em on The E Place.. Every one of these I've seen has had that problem...

My Motorola book has the 7F8 schematic but the 6KV caps are large tubulars under the chassis but not in the usual place. Those don't appear to be oil caps. That's the first time I noticed no fine tuning. That must have driven the owner a bit nuts as drift occured during warmup. My Sears B/W has a number of 7F8's also. LOVE the CRT connectors!
Can't wait to hear of the progress on this one!

If you don't want to risk turpentine, use Windex or glass cleaner with a bit of ammonia in it. That stuff will eat smoker's tar off of painted finishes, but be prepared with an old rag and a bit of elbow work to get the gummy bits off.

Masking tape is a PITA to remove unless it's been applied within the last day or so.

Nice find, Bob! I've also has some success using WD-40 to remove masking tape adhesive (particularly the petrified variety). I let it soak for an hour or two and then gently scrape with my thumb nail.

Good luck with the restoration!

-Clark

Re: Masking Tape, Naptha, a.k.a Lighter fluid should take it off without damaging the finish.
Squirt it on, let it soak a while and scrape it off with a credit card or some other non metal scraper.
I use this all the time to take old tape and stickers off of record labels.

Wow, I just noticed the 6kv caps mounted above the chassis!
Never seen that before either.

I have a channel one VT-71 with no fine tuning and I don't think it has those either, I'll have to take a look.

That has to be a very early one.
I wonder if they moved those caps because they found out having 6KV above the chassis was a bad idea? :yes:

re: Removing petrified masking tape.

First thing is to determine what finish your wood cabinet has.

By the 1940's all production lines were using lacquer, however a few small-run cabinet makers were still using shellac, so you gotta test the finish in a spot that won't show, which in your case looks like the cabinet bottom.

Shellac can be re-amalgamated (remelted) with alcohol, so flip the empty cabinet on its top and test a finish spot on the base with rubbing alcohol which is 70% alcohol and 30% water. Put an old can lid over the test spot to keep it from drying out during the 5 minute soak test. If the finish on the test spot does not turn soft after a 5 minute soak or turn white after it drys, then assume that your finish is lacquer.

If there is no change to the finish, to remove the tape, use either pure alcohol with a little Windex, or rubbing alcohol and add a trace of dishwashing soap and soak it until the tape can be rubbed off with a paper towel. Use plain Windex to remove the mess left behind. (Windex D or Windex with ammonia is the best product to use, but organic vapor rules are making this product almost impossible to find in some areas. If you have trouble, look for it at industrial suppliers.)

If the test spot was softened or whitened by the rubbing alcohol test, you have the more rare shellac finish. Get some dry cleaning fluid (it is a known carcinogen) and test that on another spot on the base. If it does not harm the finish, then use the dry cleaning fluid in the same way as before, but wear protective gloves this time, and do it outside and avoid breathing the vapor.

On a shellac finish, once the tape is removed, you can use pure alcohol to re-amalgamate the finish, and then top it off with a fresh coat of shellac. If there are bare areas of the cabinet, to even out the wood color, I'd suggest using alcohol as a shellac stripper, unless there are decals under the finish that you wish to preserve.

James

Thanks for the tips. I'll start with the least aggressive solvent and work my way up.

Funny thing is, the seller picked up the set in Ohio near as he could remember. I got it from him in the far western suburbs of Chicago. Now it's back to my place about two miles from from the old Motorola plant where it was made :)

Yes, renovatedrdios.com has them. He was lucky enough to find a mask in good enough condition to make a mold. He actually has reproduction VT71 knobs as well :)

Here's a link to the Early Television Foundation's scan of this set in Rider's vol 1.

Which Sears set do you have ? I picked up a Silvertone 8132 a while back and it's like nothing I've ever seen before inside - bunch of octals, dual push button tuner...

Careful when you reach in to change out a tube!

Then would you like to see my blond TS-4H It's original unobtainium mask is still good.:thmbsp::banana:

I'll have to visit renovated radios as some of my knobs are missing, not to mention the back.

Tom C.

Very nice find!

The mask in my blond set was in pretty good condition too. Not deformed at all, just a bit crunchy

Thanks!

I found the time today to pull the chassis. It looks like it's complete.
http://farm7.static.flickr.com/6016/...f70607c0_z.jpg http://farm7.static.flickr.com/6018/...9ca720a6_z.jpg

Here's the HV coil. I like the primitive spot welded cover. Later versions were a single piece of stamped aluminum.
http://farm7.static.flickr.com/6018/...1c684c91_z.jpg http://farm7.static.flickr.com/6150/...3df011fb_z.jpg

As for the underside, it's somewhat different from later revisions. Here's a TS-4J for comparison.
The two large metal HV caps are for the horizontal deflection plates.

One thing I find odd is that this set has all plastic insulated wire. Every other TS-4 and TS-18 chassis I've worked on used cloth insulated wires :scratch2:
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All the non HV caps are Solar "sealdtite" branded as Motorola. They don't look to be very "sealed tite" anymore ;)
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I noticed there aren't any "Do It Right" stickers on this one. You better be on the look out for factory mistakes!

Great set by the way!

That big orange doohickey is a selenium rectifier, ain't it ? They go out, too, usually makin' a very smelly mess when they do. Yeah, I'd say those caps have seen better days.

This just gets more interesting, have you found a date stamped on it anywhere?
Most of these do have one either on the back apron or on top somewhere.

The first one sold was the TS-4B. The first one with fine tuning was the TS-4H. The last chassis in that run was the TS-4J, with an "early" and "late" version.
This comes from my Wallace's Telaides book. My set is a TS-4D.

Roger that. The seller claimed it worked fine, but had lost the power cord so couldn't demonstrate it :rolleyes:

Yep, there are two of them forming a voltage doubler right of the AC line.
I learned the hard way how bad these suckers smell when they let go. It's something you never forget!

Nope, no dates anywhere. Yeah, I know what you mean though. All the other VT71s I've seen have a month and year.

I started putting together a little database form the sets I have seen.
Here's all I have so far.

It sure makes it seem likely that this set fits in nicely at the top of the list.

Can anyone else supply some serial #s and dates ?

TS-4 serial # 2425 (manufacture date: ??? )
TS-4D serial # 23149 (manufacture date: ???, 1948)
TS-4H serial # 45354 (manufacture date: July 26, 1948)
TS-4J serial # 52186 (manufacture date: Oct ??, ????)
TS-4J serial # 61454 (manufacture date: January, 5 1949)
TS-4J serial # 67607 (manufacture date: January 10, 1949)
TS-4J serial # 86923 (manufacture date: April 23, 1949)


Do you know the serial number and date of your set ?
Yeah, I have that Telaides too. I found the TS-4 in Riders volume 1. There's an early and a late version. The late matches my chassis.

Interesting, I have a TS18A serial number 338581 built on 11/29/49. I wonder if Motorola made 250,000 sets between the last one Bob listed and my set or if they started a new numbering system for every chassis type?

From a Timeline of Motorola History.
Their first set was made in 1947, more than 100,000 units were sold the first year.
If 2425 is the serial number it must be from the first week or two of production!

I just looked at my set with no fine tuning and channel 1 on the dial, it's chassis is Copper plated. It's serial# 23723 and it's a TS-4B or 4E can't quite make it out.

I have a bare chassis serial# 56000 something and it's a TS-4J, it has fine tuning.

I'm thinking yours is just a plain TS-4 with no suffix, just like it says on the label?

From your list above it looks like they were cranking out about 6000 of them a week in 1949!

OK, now I'm even more confused. I studied the Riders schematic more closely and my set is a combination of the TS-4 early and TS-4 late.

The TS-4 early has the big 0.03 mfd HV vertical caps and 6S8GT in the audio.
The TS-4 late has 0.005 mfd HV vertical caps and 6AL5 + 6SQ7 in the audio.

I have the big 0.03 mfd HV vertical caps and 6AL5 + 6SQ7 in the audio !

Also, thanks to your tips I was able to get the masking tape off :banana:
Window cleaner with alcohol and ammonia did a good job on most of it.
Then, alcohol on the residue. After that, Howard's RAF and Feed n' Wax.
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Not too shabby. Of course, all the dings, scratches and chips are still there, but it beats refinishing.
http://farm7.static.flickr.com/6027/...b961a166_z.jpg

Notice it doesn't have any side caps near the control panel ? That's another difference I just discovered.
All the other VT71s I've seen had those caps that covers screws which hold on the front near the bottom like this.
http://farm4.static.flickr.com/3383/...77515981c4.jpg

However, in the set, the control panel is held on from behind by screws.
I think the earlier design is much nicer looking.
http://farm7.static.flickr.com/6030/...9f32611910.jpg

That's the first 6 digit serial # I've come across. I bet by 1949 sales were pretty good.

I figured they sold many 100,000s of these sets overall. I wonder if the did restart the numbering with each revision as suggested. Maybe even every month ?

Nice looking set Bob :) Underneath reminds me so much of the oddball TV that I'm currently working on, same solar caps and mica caps etc.. All very interesting...Cheers!

My Sears with the 7F8's is a big (read: HEAVY!) set with a row of vertical pushbuttons for a tuner. I had help putting it on a shelf up high and now need help getting it down (soon). I started on it a bit ago and got side tracked by work.
I am curious.... That Motorola has .03 capacitors in the vertical. My Motorolas have .005 in them. My Motorola book shows the underneath couplings in the place that yours are but does not show the top ones. If the chassis mount ones are 6KV, they must be insulated better than just a cardboard sleeve (?). I had to use ceramic disc capacitors the first time to get the correct voltage rating. It amazes me how many of these little sets survived. When I first got into TV these were already considered "unfixable" due to horizontal frequency problems. The owner of the shop where I worked at the time laughed when I adopted one. He said "you'll never get it working"! It still works today!
Keep us well posted on this one!

Thanks. Yeah, they are strange little sets for sure. It's been a while since I work on one and my first impression when I saw this chassis was that there just aren't enough tubes :)

Ah, that does look just like my Silvertone 8132. Yes, very heavy! Also very weird and cool design. I picked mine up a few months ago and haven't touched it yet. I'm really itching too, but am determined to stay focused and finish off some projects first.

The 0.03 caps are metal cans with the can as one side of the caps and a single lead coming out of one end. So, yeah, the whole can is at a high potential. The cardboard sleeve is about 1/16" thick.

The horizontal caps also have a metal jacket, but one HV lead comes out of each end and the can floats.

I almost forgot the best part, the 7JP4 tests very good :D The life test is rock solid too.

http://farm7.static.flickr.com/6013/...ff0b9240c0.jpg http://farm7.static.flickr.com/6026/...55a02c2c72.jpg

looking forward to the restoration of it, and youtube videos.

It's uploading right now :D

Wonder if anyone at Motorola, Admiral, et al ever thought people would STILL be "Fussin'" over these things 65 years later ?!?

I doubt it, but then again, who knows, they may be part of the modern age and use computers now? and see this stuff?

It's too dang hot to do any soldering in my workshop so I'll do a little cabinet work. Although I did just use some Howard's products on it and it looks OK, I decided to go a step further, but not strip it.

Unlike the other VT71s I've worked on, this one doesn't have a control panel with metal tabs on the ends. Rather it's held on from behind.
http://farm7.static.flickr.com/6022/...cc234ff2_z.jpg

Nice and gooey :) It's still doing a decent job of supporting the CRT though so I'll leave it in place until I can get a reproduction from Renovated Radios.

I suppose I could unmount the CRT, but it's a pain to remount them. I'll just put some newspaper over the face to protect it.
http://farm7.static.flickr.com/6141/...2b99f2de_z.jpg

First, I very lightly sanded down the old finish to get rid of the worst of the alligatoring. Then applied 5 layers of sanding sealer with more sanding between each layer. My goal is to fill in all the defects while preserving the color.
http://farm7.static.flickr.com/6005/...caa95462_z.jpg

As for the control panel, I'll sand off what remains of the old decals and replace them. I have a nice set of repro. decals from Radiodaze, but the channel lineup isn't quite right.

On the left is a set I made a while back for a blonde set using an inkjet printer and special water slide decal paper. I figure I can carefully cutup the gold set to get the channels #s right.
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