Want to buy 800B power supply /amp

[Michael Lawton]

OK, I'll admit it, I've been bitten by the E. H. Scott bug. After refurbishing my SLRM and seeing how well it works, I saw an 800B on eBay which I could not resist for the "buy it now" price of $75 ! It is the tuner section. I now need to locate a power supply / audio amp for it, not to mention speakers, although I'm sure I can get creative about the speakers. If anyone has a power supply and / or speakers they would be willing to sell, let me know please. The serial number of this unit, according to the builder's plate is 1405.

[David C. Poland]

FYI - the power supply also has the multi stage IF amp for the FM circuits, pair of 6L6 output tubes and a VR.

Complicated system with plug interlocks preventing powering up unless proper amp and speaker are connected.

I finally color coded parts of the circuit diagram to understand the receiver I restored for someone.

FYI - House AC power travels through the set and speaker plugs in route to the receiver. A relay operates the power switch and another relay operates the AM/FM switch. Certain control positions are required for the AM/FM relay to actuate - takes carefully reading of instruction manual to understand. Some preset buttons are FM and most are AM from the factory and require a bit of rewiring to change an AM button to an FM button as those buttons also operate the AM/FM relay switch. They all have push button motorized tuning for the station presets (on the rear housing). All receivers have that big 21 pin Jones socket on the back. So a remote keyboard could be added, but only for station presets control. Some sets also had motorized volume control, and for those, the remote keyboard  also could turn the radio on and off and control the volume. The prewar and post war remote control keyboards look the same, but are wired differently so are not interchangeable, but can be re-wired.

Speakers are 15 inch ainitially with field coil and later production speakers are PM plus a power resistor inside the rear bell cover in lieu of the field coil for backwards compatablity. The tweeter operates for FM, not AM. The most common 15 inch speaker seem to be the dark teal color Jensens with center mounted tweeter, but documentation also mentions a Stephens speaker. 

The 10 tube power supply and the speaker do appear on eBay from time to time.

[Michael Lawton]

Thanks for the information, David. I reckon this will be a long, slow project, if I do end up refurbishing it... or... it will end up being a parts chassis for someone else someday. I had to snag it though for that price. That information about the speakers is useful because it means that I don't have to be ridiculously fussy about the speakers, but can substitute a resistor for the field coil with little degradation of sound. There IS a power supply on eBay right now, but it is godawful expensive, and has been "worked on" by someone before me, so I am not sure what to expect. I MUCH prefer virgin gear, even if I have to go through it completely. At least I know what I am replacing is hooked up as it was originally intended to be.

[Michael Lawton]

Well, folks, I guess I am just meant to get this 800B working. I just snagged a power supply / amplifier / IF on eBay. There was another one appeared, less expensive, and UNMOLESTED from the look of the chassis underside. The top of the chassis is somewhat rusty, but the underside is clean as a whistle. Since I don't intend to hunt down an original cabinet, but will be making my own, perfect appearance doesn't matter to me, but function does. This will be fine. I am also sure I can rig up a modern speaker with a power resistor to substitute for the field coil type speaker, just as Scott did themselves for some of these sets.

[David C. Poland]

Lots of 800B info is in this Scott Enthusiasts site, in Archives, in set folders. Much is also in Riders Vol 15.

[David C. Poland]

The most common 800B speaker.  15 inch with coax mounter tweeter.

[Michael Lawton]

Thanks, David ! I found these videos, a series of 20 of them, on YouTube. The guy is a serious antique radio restorer, and has an interesting channel with MANY different radios covered. In these he is restoring the electronics of an 800B. I don't know if he is a member of this site or not, but he surely should be. This is the first video in the series...

https://www.youtube.com/watch?v=UZ9Je97SFUc&t=350s

[Lance Hughes]

David,

     You stated, "The prewar and post war remote control keyboards look the same, but are wired differently so are not interchangeable, but can be re-wired."  I have a remote, (not placed into service yet), so how can I electrically tell the difference or what should I look for? I have Qty. 6 800B & 80B6 units, Going by the serial numbers or what Rider states, the B6 has better filtering capabilities. Is the difference in the pre and post war the serial numbers? Michael, not hi-jacking this thread but this may be great information for both of us.

David C. Poland said:

FYI - the power supply also has the multi stage IF amp for the FM circuits, pair of 6L6 output tubes and a VR.

Complicated system with plug interlocks preventing powering up unless proper amp and speaker are connected.

I finally color coded parts of the circuit diagram to understand the receiver I restored for someone.

FYI - House AC power travels through the set and speaker plugs in route to the receiver. A relay operates the power switch and another relay operates the AM/FM switch. Certain control positions are required for the AM/FM relay to actuate - takes carefully reading of instruction manual to understand. Some preset buttons are FM and most are AM from the factory and require a bit of rewiring to change an AM button to an FM button as those buttons also operate the AM/FM relay switch. They all have push button motorized tuning for the station presets (on the rear housing). All receivers have that big 21 pin Jones socket on the back. So a remote keyboard could be added, but only for station presets control. Some sets also had motorized volume control, and for those, the remote keyboard  also could turn the radio on and off and control the volume. The prewar and post war remote control keyboards look the same, but are wired differently so are not interchangeable, but can be re-wired.

Speakers are 15 inch ainitially with field coil and later production speakers are PM plus a power resistor inside the rear bell cover in lieu of the field coil for backwards compatablity. The tweeter operates for FM, not AM. The most common 15 inch speaker seem to be the dark teal color Jensens with center mounted tweeter, but documentation also mentions a Stephens speaker. 

The 10 tube power supply and the speaker do appear on eBay from time to time.

[Michael Lawton]

No problem, Lance, the more knowledge we can share and gain the better. I'm not going to be adding a remote control to mine, just the tuner and power / amp / IF chassis, and the speaker; and maybe a turntable, probably a modern one, with a small pre-amp if needed to match the input.

[Norman S Braithwaite]

The 800B remote has two ground returns, one for AM and the other for FM.  Current through the ground return is used for switching between AM and FM.  If the remote cable has plastic insulated wire, it is post war.  If rubber insulated, pre war.  It is easy to make a post war remote keyboard work for a pre war set by connecting both ground returns to the correct ground wire for pre war.  The converse is not so easy.

[Norman S Braithwaite]

Also, the remote keyboard can be used to turn a non-remote set on and off by adding two wires and the indicator light on the remote keyboard can be made functional by adding a 47-ohm resistor.

Norman 

[Lance Hughes]

Oh WOW!! Thanks Norman. Information sent to a word document for reference.