Tech-Master NIB TV Kit #5516
 

Guys,

I won this 1955 TV kit NIB at an auction today. It does not come with a CRT.

The parts haven't even been removed from the carton! I talked to the seller and he said that he removed the instruction sheet to see what CRT it uses, but he didn't have that type. Otherwise completely unmolested. Because he already looked at the instruction sheet, I pulled them from the envelope.

What a find!

Of course the real question is should I keep it this way or build it?

Photobucket isn't cooperating so no pictures right now. I did post some pictures over on ARF.

I wouldn't have any reservations building that. Looks like any 70 degree electrostatic focus CRT could work, but I'm guessing that chassis is set up for a 17" tube, like a 17HP4.

http://i452.photobucket.com/albums/q...pskffw6mag.jpg

Some pictures.

http://i1060.photobucket.com/albums/...psjs5iwtmv.jpg

http://i1060.photobucket.com/albums/...psprlmg0df.jpg

http://i1060.photobucket.com/albums/...psd4alkswo.jpg

http://i1060.photobucket.com/albums/...pscv31txbv.jpg

http://i1060.photobucket.com/albums/...psmlptpeus.jpg

http://i1060.photobucket.com/albums/...psctpnlkyw.jpg

http://i1060.photobucket.com/albums/...psydywvpbm.jpg

Kevin,
Thanks for the reply. I needed that info for a CRT! Where did you get it? Was it a page from an Allied Catalog or such?

I also think it uses a magnetic focused CRT. There is a fly-back transformer and the schematic shows a HV lead going to a 2nd anode on the CRT.

I think the ad has a typo.

The listing is from my 1956 Burstein Applebee Co. Radio Master catalog.

Magnetically deflected, but electrostatic focus, unless your kit came with a electromagnetic focus coil? Your build manual must share some information on compatible picture tubes?

OK, I'm confused. There doesn't appear to be a focus coil used in this TV.

Here is the schematic:

http://i1060.photobucket.com/albums/...ps7jictfwd.jpg

The manual suggests "A low-voltage electrostatic or self-focus picture tube is recommended for use with this receiver."

That's because it's intended to use an electrostatic focused CRT. Which is nothing more than a DC voltage that connects to the CRT's focus pin. I think on a 17HP4 it's G4, but I can't make it out on your schematic.

https://frank.pocnet.net/sheets/127/1/17HP4.pdf

On the schematic, pin 6 is grounded.

That makes sense. Notice the -56-310v range for pin 6 on the17HP4 spec sheet. My experience has been that those electrostatic focused types are not very sensitive to what voltage that pin gets tied to. So they basically are self focusing. Don't think I've ever seen a electrostatic focused set with an adjustable control?

OK.

I've looked up some CRT's that would work:

17HP4
17TP4
17CGP4
17CP4B
19QP4
20HP4
20HP4E
20LP4
20MP4
21FP4D
21AFP4
21YFP4

Get new caps instead of using the wax caps that came with it, also use new electrolytics too.

Be careful, it looks like a hot chassis set.

And be sure that the CRT you use has the same heater current as that of the heater string.

It's a low B+ hot chassis design, similar to the AC-DC Emerson set I just restored.
The CRT used would be a 17HP4, 20HP4 or a 21YP4. I would stick with the 17HP4 type, as the design is a slightly lower high voltage supply, intended for smaller screen sets.
I see it uses the tried and true synchro-guide horizontal circuit. :thmbsp:
All the CRT's at the time were 600 ma, 6.3volt heaters.

Will do on all counts. Thanks