Thanks! That sure does look similar and you've done a nice job on it :thmbsp:
It's good to know some else out there is working on one too. Other than the little 7" 400 series, I don't see Sentinels too often. I have the Sams and Beitman's for the 422 if you need a copy.

I've just about got this set all squared away. First issue - the top being clipped and twisted was due to my 1077B being out of whack :stupid: I really need to properly overhaul that bugger.

Second issue - the brightness gradient was due to the CRT being mounted at a bit of an angle. See that gap at the top - the tube is tilted back a little in the yoke.
http://farm3.static.flickr.com/2719/...81847406_b.jpg

I fixed that up and the brightness is uniform now. I just need to tweak that yoke rotation and lower the picture a little to take care of those dark bottom corners. So close to being done :D
http://farm3.static.flickr.com/2784/...3617d76f_b.jpg

A few more tidbits about this set.

It has 14 channel positions - one blank before #2 and one blank after #13 ?!?

It also has a color converter. Would this have been for a color wheel ?
http://farm5.static.flickr.com/4022/...d3b47536_b.jpg

While looking through my parts stash, I came across a NOS Merit HOT for this chassis. Between that and the spare CRT, I should be able to keep this set running a long, long time.
http://farm3.static.flickr.com/2801/...db0176e18c.jpg

Is this a big drum tuner? It's likely those blanks could have strips installed for specifc UHF channels that were in your area... and they gave you provisions for two channels instead of just one.

I think it would be really cool to find an early set with a UHF channel strip installed. It's always possible to have one and not realize it. It would be easily overlooked. The tuner drum in my Zenith PH has a empty spot where one could easily be installed. The drum on my Bendix does not. Makes me wonder about the Sentinel 7" sets... there's an extra click in the tuner and it's not labeled on the bezel.

Greetings from FixitLand!

My '52 Zenith K1846R has a Channel 27 strip instead of Channel 3. When the set was new, KPTV Channel 27 was the only station in Portland, Oregon. We didn't get a VHF station until KOIN-TV 6 came on in 1953. Unfortunately for me, the folks from whom I got this set misplaced the Channel 3 strip long ago...

Take care,
--
J. E. Knox "The Victor Freak"

Nowadays, Ch 3 is the most important spot on the dial for us! Too bad they didn't stick that 27 strip somewhere else. It's a good thing most all VCR/DVD machines, modulators, and satellite boxes, etc. give you a choice of using Ch 3 or 4.

---

Ditto. As much as I like my old 10" B&W sets, I don't watch them often. Most of the fun to me is in bringing them back to life and cleaning them up real nice. Then I push them to the back and pull out another dead one to work on. I have a dozen sets waiting out on the back porch :D

I bet that statement can apply to many of us here! :yes:

Not here. 1950's vintage TV's are rare as $3 bills.

I'm calling this project officially done. I even stuck a TV lamp on top :D

http://farm5.static.flickr.com/4003/...41c33ca7_b.jpg

I think so, but it's under a metal RF shield and hard to get a good look at. Do you think a tuner designed for VHF could go up to UHF frequencies :scratch2:

Apparently the answer is yes based on my experience and I could kick myself now for not truly appreciating it: a 1951 Zenith porthole I once owned (a VK member has the same set as his avatar) picked up o.t.a. channel 35 in the channel 2 position. I bought it from an antiques merchant who claimed to have gotten it from a very elderly couple whose primary set it had been since new. That was in 1991. If true, the original owners sure had one ace TV technician at their disposal considering channel 35 didn't come on the air until the set was about 20 years old!

That is a neat TV lamp. Like to find one to put on top of my 1950 Zenith Porthole TV.

Is it an antique or is it something that can be easily found today?

Vintage TV lamps are so popular that they have a category all their own on eBay. I see 231 listed today.

http://collectibles.shop.ebay.com/TV...053%2C1404%2C1

Phil

Well I be darn. Did not know.
Never heard of a TV lamp.
Even not knowing, they are still visually appealing.
I guess this shows that some designs are timeless.

I have a Sentinel similar to yours... trying to remember... that shied isn't easily removed?

It would seem those UHF channel strips are specifically designed to work in the VHF tuner. The original tuner strips are usually numbered on the strip, so, follow the numbers as the drum turns. If you come across a number that doesn't fit in the sequence, then you've got one.


That's the truth!! They've got some crazy lamps out there, too!

Some sets, particularly Zeniths, had turret tuners with removable channel strips which could be replaced by UHF strips. The latter would be inserted in place of unused VHF channels in a given area. For example, if your area had channels 2, 4, and seven, and a new UHF channel went on the air on channel 52, you could get a UHF strip tuned to that channel, insert it in an unused position in your TV tuner, and presto, you would now have reception of the new station (provided, of course, that you had the proper UHF antenna; in the days of UHF channel strips, this usually meant a good outside antenna, although if you were very close to the transmitter you could get by with a loop or an indoor UHF antenna).

The maximum number of UHF channel strips that could be installed in any TV tuner is theoretically 12, although in most areas that number was somewhat smaller, especially in New York and Los Angeles which already have seven VHF channels. In these cities, a maximum of five UHF strips could be installed in the tuner, in place of unused channels 3, 6, 8, 10 and 12. In most metropolitan areas, however, there are far fewer VHF stations, so the number of UHF strips that could be installed in the tuner could be as great as nine or 10, although I doubt if any major US city (with the possible exception of Los Angeles) has anywhere near that many UHF stations. In my area near Cleveland, there are only three VHF stations on channels 3, 5 and 8, which leaves nine unused positions. However, there are (never have been) nearly that many UHF stations in this area; before digital, we had UHF channels 25, 43, 55, and 61. When UHF channel strips were popular, Cleveland only had one such station (PBS, then NET affiliate WVIZ) on channel 25, so only one strip would be required, and in fact the MATV (master antenna TV) distribution system at the local elementary school in my old neighborhood downconverted that station to channel 4, so no strips were required or used in those sets to receive the station; as a matter of fact, our TVs were all RCAs which I don't think could have been used with UHF strips.

I think the idea of using UHF channel strips to receive such stations on unused VHF channel positions was patented by Zenith early on, and could not have been used by RCA or any other TV manufacturer without risking a patent infringement suit--or worse. However, there is a way set owners could set up their turret VHF tuners to receive only the local VHF stations in their area--by removing all strips occupying unused channel positions, leaving only the strips for the active stations in the area. This would allow the viewer to switch from one local station to another without going through unused channels, and would also allow the use of UHF strips in the unused positions. Using my area as an example, grouping channels 3, 5 and eight together would leave nine unused channel positions, in which UHF strips for channels 25, 43 and 61 could be installed (further reducing the number of usused channels to six). This would afford the viewer the convenience (especially when tuning by remote control) of tuning to his or her desired station without having to flip through unused channels 2, 4, 6, 7, 9, 10, 11, 12 and 13, as is possible with today's electronic tuners which have an add/delete option for setting desired vs. undesired channels in a customizable scan list. The unused VHF strips could and should be saved in case the set owner moves to an area with different channels; of course, this would mean getting new UHF strips for the different UHF stations in the new area.

Needless to say, however, this is an outdated method of setting a TV tuner for receiving only the area's active channels in this day and age of electronic tuners. It cannot be used with older sets nowadays anyway, as older sets used with ATSC->NTSC converter boxes require that the VHF tuner be set to channel 3 or 4 and left there, all tuning (and presumably on-off power switching of the TV, not to mention volume control and muting) being done either at the box or via its remote.

I grew up in an area that only had UHF at first, and would say that they sorta worked. Strips were not recommended for fringe reception. Although the strip had tuned circuits for the UHF channel, gain must have been very low. I believe the oscillator was run at a sub-harmonic of the desired frequency and then multiplied by components contained on the strip. At the time, continuous UHF tuners seemed to work better than the Standard Coil tuner strips. Few had RF amp circuits, but some UHF band boosters were available. Poor converters and low power transmitters made for a fairly poor television debut, but what the heck...it was TELEVISION!!! :)

jr

Maybe, but I gotta pull the whole chassis first and my next project is already up on the workbench. I'll take a look one of these days and let you know what I find.

There's a whole website devoted to them: http://www.tvlamps.net/
What a collection!

TV lamps were used to provide a soft light on top of the set so that the room in which the set was located wasn't totally dark when the TV set was on, per recommendations by eye doctors of the time (1950s) discouraging watching television in pitch darkness. IIRC, my folks had one of these TV lamps on top of our first set; it was in the shape of a horse, with a little 7-watt Christmas tree bulb in the base.

Some of the fancier TV lamps even included a digital clock in the base. One manufacturer of these lamps (don't recall whom right now) had a TV lamp that was actually shaped like a miniature television, with the clock in the center of the "screen" and the lamp arranged so that it illuminated the area around that screen and the clock as well. The clock mechanisms were motor-driven digital clocks made by well-known companies such as Pennwood Numechron, the same folks who brought us the first motor-driven electric digital clocks.

I wouldn't be surprised if we eventually see a comeback of these TV lamp clocks, with updated designs, including LED clocks, of course. The diffuser could be in the shape of a current TV actor or prop from a popular show, and the lamp bulb would probably be an energy-saving LED or other low-power light source.

I have a few of those numechrons too.
http://farm5.static.flickr.com/4053/...20940a51_b.jpg

Thought I'd bump this thread to the top because Bob's done a couple recent reveiw videos on this set. I've been finding it very fascinating because I picked up this sets bigger brother earlier this fall. Basically it's the same chassis but with a 19AP4 CRT. Originally I picked up the model 425-CV because I was in need of a good 19AP4 for my DuMont RA-119. But the more time I spent researching the Sentinel, the more I wanted to keep it complete. Recently I finished restoring the chassis. The cabinet is in decent shape and only needs a little touching up. I currently have the chassis back in the cabinet and have been watching it over the holidays. Turns out it's a fine performing set.

http://i452.photobucket.com/albums/q...g?t=1388859445

http://s452.photobucket.com/user/Kue...Sentinel%20525

Beautiful set :thmbsp: I hope you had an easier time with service info that I have. I've never found a 430 specific schematic and the 423/425 info doesn't quite match mine.

So as Kevin mentioned, I have pulled the Sentinel out for some servicing. All this time I've been running it on the weak CRT it came with but it's nearly dead and needs replacing.

http://farm8.staticflickr.com/7367/1...479bdbdc_c.jpg http://farm9.staticflickr.com/8092/8...749ec93e_c.jpg

I guess the sales flyer claim of 17" was accurate after all.
http://farm3.staticflickr.com/2851/1...14ac0955_c.jpg

Here's a shot of how the set was playing. The CRT lacks focus and it gets worse as the brightness is increased.
http://farm6.staticflickr.com/5508/1...1ec683ce_c.jpg

Back when I got this set I had assumed it had an early 16" CRT in it, but it turns out I was wrong. If I had just peeled back the rubber trip on the CRT I would have found this label showing it's a rebuilt 17BP4!
http://farm8.staticflickr.com/7332/1...e200a5e1_c.jpg
So I can't really using the nice aluminized 16KP4 I found :( I do have a couple good 17BP4s although neither is aluminized. I chose the one with the best external coating and installed it.
That's too bad though because it means my 17T13 with dead CRT will have to wait. I then checked all the tubes, found six weak and/or shorted and replaced them.

Back when I restored this set the first time around, I had noticed a gradient in the brightness. Here's a shot of the same issue with the new CRT. I suspected it had to do with the vertical retrace blanking circuit. So I disconnected it and the brightness is now uniform but the retrace lines are back. I'll play around with different RC values and see if I can get it working correctly.

http://farm3.staticflickr.com/2834/1...e24822ec_c.jpg

Think I ended up with a .01uf and a 5.6k in series for retrace blanking. There's definitively a trade off between max blanking and brightness at the top of the screen, as well as overall condition of your CRT.

Here's the signal on the cathode. It's pretty obvious now why there's a brightness gradient.
I reduced the cap from 0.1 to 0.01 and increase the resistor from 1.5K to 5.1K and it helped a lot :)
http://farm3.staticflickr.com/2893/1...8abbe79f_c.jpg