Scott philharmonic fm with remote: Power supply

[Timothy Murphy]

I joined because my question and I were referred by the Antique Radio Forum Moderator! So, here goes...

The question is:

       "Is there an expert here who can explain the differences between the power supply for a Philharmonic FM with remote, and without? As far as I can see, there is an extra plug on the side (3 instead of 2), and an extra transformer and electrolytic underneath. Does anyone have a schematic showing the differences from the non-remote power supply? An explanation why they are there? 

        "In a follow-up, I've discovered that the "third hole" is for a four prong plug connecting the power switch cable from the tuner. This was a change in the later models - presumably including those with FM. Earlier models had a separate cabinet-mounted on-off switch wired through the cable feed-in to the ps. So two holes, not three. Now, what about that transformer and electrolytic and diagram? Anyone? 

       "Last try. Here are a couple photos to let you see what I'm talking about: One with the transformer (and remote), one without. Any thoughts?"

So, proudly I turn my confusion over to the pros from Dover! Thanks.

Attachments:

[Timothy Murphy]

Norman:

Thank you for that kind offer. Unfortunately I think that the site limits prevent a full detail picture. But not to worry: My speculation is that the former owner of my set hooked up a substitute power supply with the new wires. At least I will be able to test that theory with my available equipment.

As to the transformer, I speculate further that the post-war 800b series used the identical unit. I'll check that also since I'm lucky? enough to have several of those sets around. 

But pardon one more really last thought ... I suspect that our discussion may have pushed the conventional wisdom timeline for the 800b style remote set-up, back from 1946 to at least 1937. The Model 16 transformer and control head connector at the tuner (I did not upload a photo of that), look very similar to the 800b. If that final speculation is true, then it has been a good day's work indeed.

Tim Murphy

Norman S Braithwaite said:

Tim:

The Scott part number is stamped on the cover near the top edge.  It is a number in the 5000 range.  This transformer was most likely made by the EH Scott Radio Laboratories (formerly Scott Transformer Company) and, unfortunately, we do not have the exact specifications.  Transformers from other companies providing control voltages, fortunately, are not uncommon.  When I have time I should energize one of the control transformers and determine the voltage.

I was unable to speculate on the purpose of the added three twisted pairs due to the small size of the photo.  If you can post a large close-up photo showing where these wires are hooked into the circuit, I can speculate as to their purpose.

The control transformers in your chassis are where they are normally found for the particular models.

Norman

[Kent King]

Tim -

A couple things...first, on a Philharmonic with the crossover network, it is fairly complicated. There are two cables from the tuner to the PS, one is the primary set cable, the other is the on/off (and optionally the control voltage if it is a RC set). There is also a small 3 wire cable coming out of the tuner to the crossover, which cuts out the tweeters on all bands except FM. Finally, the main speaker cable from the crossover unit plugs into the power supply, since the supply contains both the power and the final amp stage.

Based on the photos, I'm sure these cables are not original....not sure what they were trying to do however.

Lastly...the remote control unit on the 800B is the same as that used on the pre-war sets. In fact, the control heads can be interchanged. I documented and published a wiring diagram for these back in the 90s...I'd have to dig it up. Scott used the same wiring....things like the ribbon cable changed in design/appearance pre-war to post-war, but electrically they are interchangeable.

Kent

[Timothy Murphy]

Kent:

  The information about the 800b interchange is helpful and reassuring. I began to believe that was the case as we concentrated on the ps transformer mountings over the series of several models. A copy of your wiring diagram for a "standard" Scott remote control ps voltage setup would be enlightening.

  Although the tweeter connection options are a practical bridge that I'll eventually need to cross, my hobby interest obtains to the wired remotes. I recently in fact purchased economically a very nice 1933 Stromberg-Carlson Tel-lec-Tor control head on E-Bay, where it had been misidentified as a radio.

  So in place of the tweeter issues, I wonder if you'd care to comment why the Scott control heads have not been reproduced? They are rare; go for $800-$1500 when offered; are common as we've shown to at least 4 models over more than a 15 year manufacturing cycle; and are constructed from common mechanical parts. One would think that in this age of 3-D printers, a few clones could be sold for a small profit?

Tim Murphy 

 

[Norman S Braithwaite]

Tim:

First, the remote scheme employed by Scott is the same that was used by a number of other companies in one form or another after first appearing around 1929 in a Colonial receiver.  It is fairly clear that the scheme was not patented.

Second, in my humble opinion, the pre-war and post-war remotes are not directly interchangeable but with some effort can be modified for use with each other.  The post war remotes had separate commons for AM and FM thus allowing the receiver to switch between AM and FM for appropriate stations.  It was a requirement that the tuner chassis have the distribution of AM and FM push buttons matched to the remote.  Otherwise, a substantial effort would be required to modify the mechanical internals of the remote to match the distribution of AM and FM push buttons on the tuner.

Finally, Jim Schwalbe had reproduced the case, push buttons, and bottom plate for the remote and had collected a large number of 21-pin Jones plugs.  I have the unsold and unclaimed remainder of the reproduction stock.  The internals and wire ribbon have not been reproduced.  I am willing to trade up to three reproduction "kits" for three faithfully reproduced internals, two pre-war and one post-war.

Norman

[Timothy Murphy]

Norman:

It seems that the trading floor is open! Although I do not have any internals to trade, I'll be happy to host the negotiations. I have a couple nice 1930s Capehart remotes but their home is permanent here.

A nice CAD file of the Scott internal parts would be an asset to collectors and a start towards production. Meanwhile photos would be welcome, but I have not seen one shown of the Scott head disassembled.

I have investigated the cable and have isolated several potential sources. The last one I heard from has been:

Offray Specialty Narrow Fabrics, Inc.

360 Rt. 24

Chester, NJ  07930

Ph: 908-879-3626

  We were discussing a 4" wide 16 conductor woven fabric.

I do recall some discussion in the 800b manual of changing the location of FM and AM selector buttons on the tuner. My recollection is that physically relocating terminal wires (or was it the common ground?) on the push button riser was part of the process.

Norman S Braithwaite said:

Tim:

First, the remote scheme employed by Scott is the same that was used by a number of other companies in one form or another after first appearing around 1929 in a Colonial receiver.  It is fairly clear that the scheme was not patented.

Second, in my humble opinion, the pre-war and post-war remotes are not directly interchangeable but with some effort can be modified for use with each other.  The post war remotes had separate commons for AM and FM thus allowing the receiver to switch between AM and FM for appropriate stations.  It was a requirement that the tuner chassis have the distribution of AM and FM push buttons matched to the remote.  Otherwise, a substantial effort would be required to modify the mechanical internals of the remote to match the distribution of AM and FM push buttons on the tuner.

Finally, Jim Schwalbe had reproduced the case, push buttons, and bottom plate for the remote and had collected a large number of 21-pin Jones plugs.  I have the unsold and unclaimed remainder of the reproduction stock.  The internals and wire ribbon have not been reproduced.  I am willing to trade up to three reproduction "kits" for three faithfully reproduced internals, two pre-war and one post-war.

Norman

[Norman S Braithwaite]

Tim:

I will take and post some photos of the remote internals but it will have to wait until I catch up at work.  Most of the Scott remotes used a 2-inch wide, 20-wire folded cloth cable (two layers thick).

Norman

[Timothy Murphy]

Norman:

  That is a characteristically generous offer. Too bad that work might interfere! The idea of cloning a few control boxes might have legs. The cable can certainly be obtained. As to the internals, if they are stamped sheet metal instead of castings, one way to duplicate them is to non-destructively dismantle an example and scan it (3-D laser) piece-by-piece to CAD files. It then becomes fiscally reasonable to computer cut as many parts as desired, even one set at a time. It is a thought, anyway.

Tim Murphy 

[Norman S Braithwaite]

Tim:

I have posted photos of the switching mechanisms within the Scott remote keyboards.  If you have not already spotted them upon opening the site, the photos can be found here...http://ehscott.ning.com/photo/prewar-1.

Norman

[Timothy Murphy]

Norman:

  Thank you so much. My jaw is still lost on the ground. The prices that I have seen paid for a component made out of a molded case and a phenolic board as simple as dirt! I do not know what to say. Was it maybe a platinum pilot light?

Tim Murphy  

[Norman S Braithwaite]

Tim:

The pilot light is a standard telephone PBX type.  If it appears that you will be able to have the guts reproduced, I can provide more details.  There are two or three other collectors who have the reproduction cases and whom may be interested in reproduction guts.  Also, I have indicator lamp lenses that are not exact but are very suitable for the remote keyboard.

Norman

[Kent King]

Tim -

The prices do not reflect the technology but only the rarity. Most folks cannot make a good reproduction, and the original units are just very hard to find. That is why making a good reproduction could be lucrative...based on what I've seen over the years, I'd say the ratio of remote sets to control heads is probably at least 20:1.

Timothy Murphy said:

Norman:

  Thank you so much. My jaw is still lost on the ground. The prices that I have seen paid for a component made out of a molded case and a phenolic board as simple as dirt! I do not know what to say. Was it maybe a platinum pilot light?

Tim Murphy  

[Timothy Murphy]

Gentlemen:

   Well, I have arranged with my dentist for a jaw repair, so I'm able to continue the discussion. I'll confess to owning a tidy collection of fairly obscure cable operated control heads, dating from the early 1930's to the 1970s. But as an indication of its rarity, I do not have a Scott.

    I wonder if the market would be better served with a replacement control head rather than a clone, and a little receiver box for the set attached to a plug-in Cinch-Jones connector, using off-the-shelf infrared technology such as Alps?

Tim Murphy