DuMont "Hanover"

[bigolds98]

I just picked this up today and I am not to familar with DUMonts I know they were exspensive at the time can anyone tell me any info about this TV. I did not want to try it because the cord is cracked. Over all it is in ok shape there are sratches and some nicks but it looks really cool. Any Info would be Great. Thanks.

[jeyurkon]

Originally Posted by bigolds98

I just picked this up today and I am not to familar with DUMonts I know they were exspensive at the time can anyone tell me any info about this TV. I did not want to try it because the cord is cracked. Over all it is in ok shape there are sratches and some nicks but it looks really cool. Any Info would be Great. Thanks.

Nice save! I'm sure you know there's more to worry about than a cracked power cord before trying it out.

I don't know much about them but the Antique Trader Radio and Television guide shows it as being a 1950 model worth about $100 depending on condition.

John

[Sam Cogley]

Very cool! My grandparents had that set, it was the first TV in their neighborhood. All of the neighbors would come over on Saturday night to watch TV. My dad found the cabinet, sans guts, in storage in the late 60s. He cut the depth down and turned it into a stereo/record cabinet, which still resides in their basement. It's nice to see pics of a complete example! I'll have to remember to show him these pics when I'm home in a few days.

[M3-SRT8]

Yup. RA-109 Hanover. Uses a 19" CRT, frequently gone to air. I would check that first before rebuilding.

DuMonts are great Telesets. I have four of them, two are working. One, an RA-105B "Sussex" with a 15" CRT, is my most reliable Set.

Recap 'em totally, and check the usual suspects, i.e. ww and hi value resistors, etc. Clean the Pots. Should be good to go.

LJB

[Tubejunke]

Amoung the most interesting, well built, and HEAVIEST sets I've ever seen. Mine has been gone for years, but I miss it. Seems like I remember about 35 or more tubes. Wow! It had the A.M. radio. I don't think this one has the optional A.M. radio.

[Tony V]

I see a booster hanging off the back of the crt so it may be toast.

[Charlie]

Wow... look at the power tranny in that thing!! And I thought the tranny in my 29JC20 was big... the transformer in that Dumont is huge!!

That's a really nice set, however, that booster is not a good sign. Perhaps it will still make a picture, but don't get your hopes up.

[Tubejunke]

Those are the largest television power transformers I have ever seen. I remember pulling a Dumont chassis like that, and always having to remember to position myself just the right way to be ready for all of that weight all on one corner of the chassis. Seems like the chassis was pretty easy to remove, but awkward and heavy. I hate it that so many of those great sets had lousy 19AP4 CRT's. Mine was weak, even with a booster, over 20 years ago.

[bandersen]

I kinda admire a company that went all out with their design. Huge transformers, high tube count, innovative circuits, etc. Maybe someday I'll be lucky enough to own one

[jshorva65]

Originally Posted by Charlie

Wow... look at the power tranny in that thing!! And I thought the tranny in my 29JC20 was big... the transformer in that Dumont is huge!!

That's not JUST a transformer, it's part of a pretty sophisticated VOLTAGE REGULATOR and power-line conditioning arrangement. There's a 1.75 uF "bathtub" capacitor connected across the secondary, and the construction of its core and windings are such that the output waveform is a virtual squarewave (flattened sinewave, actually) whose peak voltage is 1.3 times the RMS (as opposed to conventional transformer specifications where peak is 1.4 times RMS). The normal operating condition is very near the point of magnetic saturation (with accompanying high core losses), and it's NORMAL for this transformer to run significantly warmer than a conventional transformer due to the lower efficiency. Despite the high value of iron losses, however, the voltage regulation of this transformer will be far superior to that of conventional transformers for a large range of line voltage or load current variation. You will note that the end bell will be marked "Sola Electric Co." as Dumont custom-ordered these Constant-Voltage Transformers from Sola for use in several of their largest-screen models (mainly RA-108's, RA-109's, and the RA-119 "Royal Sovereign" if memory serves correctly) from the 1950-1952 model years. Zenith also purchased Constant Voltage power transformers from Sola Electric for some of their early solid state modular color chassis designs (Chromacolor and/or Chromacolor II) during the 1970s. I distinctly remember the large transformer and "bathtub" capacitor combo on the earlier "horizontal-chassis" Zenith modular sets (Chromacolor) and vaguely remember a similar arrangement in the vertical-chassis (Chromacolor II) line. Other manufacturers may have also used Sola Constant Voltage power transformers in their higher-end models.

When first powered up, these transformers produce a distinctive "fluttering" sound for a few seconds, which changes to the normal faint hum emitted by a conventional transformer. The startup sound resembles the sound of a tiny refrigeration compressor starting up.

These transformers are also rumored to withstand heavy overloads for longer durations than a conventional transformer, although I've never deliberately run one of them into a dead short to "find out" if the rumor was true. Some 20 years ago, however, I did perform some pretty extensive testing on one of these transformer / capacitor sets that I had bought as surplus and eventually used that power transformer and its accompanying capacitor in the power supply of a custom tube stereo power amp I had designed. I may still have the output voltage-versus-current tables and graphs from those tests among my notes, but they are almost-certainly stored in a large box of notebooks buried somewhere in the attic.