The two mods that I've seen in prewar sets are 1) a 12 channel tuner, and 2) a FM audio detector.

I've never seen a 1-F-5 with a 12 channel tuner, though it would have been possible to do.

Also, I've never seen a FM detector in one either.

Most likely your set has the original circuits.

Since the Andrea, and in fact most electrically deflected sets, don't use the horizontal signal for HV, this set would have been relatively easy to convert.

I have no experience converting 441/60i to 525/60i, but a little over 50 years ago I did convert a 405/72i to 525/60i and it was much harder to do than I had expected. The worst part was, at the time, I was unable to determine the exact specifications of the set. Not having an accurate frequency standard, nor a scope, I used an actual TV signal and a little red-neck engineering. I was so far off on horizontal that I had no idea how far I was off -- all that I knew was it was way too high, but I could see the wide vertical signal rolling, so I first converted the vertical to 60i and then was able to see the horizontal well enough to bring it in, but when I did, the drop in B Boost was enough that it messed up the vertical again, and so I had to redo the vertical.

When I got it on speed the V & H size and linearity controls were out-of-range. If memory serves me correctly, I had to change some capacitors by over 50% and adjust resistance.

Jas.

James,
All pre-war televisions, electrostatic and electromagnetic, except the German E1 used brute force HV developed right from the mains. Only the E1 used a flyback. There is no issue with changing the horizontal frequency on any of these pre-war sets. I have run my 12" electromagnetic RR359 from 240 through 819 lines with no changes to the circuitry, just adjusting the coarse horizontal control.

Darryl

Thought comes to mind if that set could handle 1080i or 720p. B&W HDTV, use the luma jack. Though 720p would be nearly the same as 1440i, which seems too much a stretch beyond 819i. :scratch2:

In Nov 1941 Andrea put out an upgrade kit and 3 page instruction sheet to convert the 1F5 to the new standards. It included new antenna & oscillator coils and a new sound IF transformer in addition to a few new resistors. Reading through the instructions the tuner coils were changed to allow the tuner to receive the "old" new channel 2 at 51.25MHz & new Channel 3 at 61.25MHz.
The conversion did not add an FM detector to the audio circuits, the new sound IF transformer allowed the set to be tuned easily for slope detection for the new audio standard FM.
The instructions describe tuning the audio first to 8.25MHz and final adjustment is peaking the audio at 8.15MHz

Also included was an extension shaft and knob to make the sound sensitivity (fine tuning) control accessible from the outside.

So if a set has the FT control knob on the right side of the cabinet there's a good chance it has the mods.



Chuck

Well, the set's still living in the car :o but I did manage
to take some more pictures before it got dark today.

It DOES have the factory label showing serial #10444.
(I wonder if that makes this the 444th one made?)

http://farm8.staticflickr.com/7423/1...1e064eea7a.jpg


There is a control knob on the right side of the cabinet.
Chuck: this means it has the modded tuner? I wonder where
shaft and knob on the front left disappeared to?

http://farm6.staticflickr.com/5500/1...39d8edfd08.jpg


Nothing on the left side:

http://farm8.staticflickr.com/7448/1...02502534b5.jpg


Here's a shot of the tuner area of the chassis.

http://farm4.staticflickr.com/3737/1...aee36e44c6.jpg


I removed the CRT.

http://farm3.staticflickr.com/2872/1...101259b4fc.jpg


Sharper eyes than mine had already verified that it had to be a 5AP4.
It's hard to see in the photo but there's a faintly visible label that says
1805P4 on the neck. The key is broken off the base, but it still has a
nice, shiny getter!!! Date code is 2-43 indicating that it's a replacement.

http://farm8.staticflickr.com/7417/1...e9928c9b4a.jpg

Stay tuned...

David,

A Feb 1943 CRT replacement. That would make it a wartime replacement. Some one had some pull. Surprised RCA was making these tubes during the war. Anyone know if they used 5AP4's in military applications? Radar perhaps?

-Steve D.

Suppose it wasn't a wartime replacement? I think that tube was likely acquired when postwar surplus became available.

That seems more likely.

Dave, the knob on the side is for fine tuning. Most sets only have a hole there for screwdriver adjustment.

Your tuner is there, just the shaft is missing, probably broken off inside. It should be easy to repair. Yours is a 3 channel version.

We have serial numbers from 10028 to 10991 in the database. I don't think they made 991 of these, so I doubt if yours is the 444th one made.

Only saying that the Feb. 1943 build date suggest that the tube was manufactured during the war, even tho it may be post war surplus.
And why was RCA building these tubes, unless they were a priority for war time use?

-Steve D.

The military did use television equipment during WWII: http://www.qsl.net/w2vtm/mil_television_history.html

Maurice demonstrated a working setup at the Early Television Convention in 2007. If I recall correctly, the images on the CRT were in green. The Block 3 monitors shown are clearly green. Does anyone know if the Block 1 monitor might be a P4?

Is it odd that the set has the prewar tuner yet a crt that was likely war surplus? hmm Was that set used after the war?

Might get a better idea once you pull the chassis. Be sure to post a shot of the underside when you do.

Late to the thread. INCREDIBLE find! I've enjoyed reading the story and seeing the photos.

Rider 1 included a number of prewar TV schematics. I'm sure they wouldn't have bothered to do so if there wasn't at least a perception of practical need.

I don't believe the number "2-43" is a date code. My 1F5 has the same metal based CRT with the number "8 43" no dash, stamped on the base. The set has never been tampered with, no tubes changed (they all have correct RCA date code XE3, May-June 1940), 2 channel tuner, and not upgraded to the new standards.

I believe Dave's CRT is original to his set. Any thoughts or comments?

Chuck

We tested the CRT at the Early Television Museum. It's bad. :tears: I'll have to source another 5AP4 or replace with a 5BP4. And add this one to the "round tuit" pile outside the CRT rebuilding room!

Not affiliated but this has been on eBay for about 3 weeks now. Kenrad 5BP4. Originally he had three, but is now down to two

http://pages.ebay.com/link/?nav=item...333178&alt=web

....and that is 15 minutes from my house. I can always pick it up for you if needed.

Thanks Tim! I'm currently shaking the bushes locally. (New Jersey-area collectors seem to have at least two of everything squirreled away!) But I may very well end up wanting to take you up on your offer. In any case, thanks a bunch for thinking of me!

-- Dave

Thanks to the help of fellow collectors (gotta love this collecting community!) I've been successful in my efforts to locate and purchase a good 5AP4 CRT for this set. Looking forward to receiving it at the next Early Television Convention.

Dave

You have the patience of Job.

Doubt I'd be able to wait that long.


Chuck