Early versus Late 800B Tuning Switches

[Joseph W Strickland]

Today I finished printing out the entire set of Service Manual pages and began reading through them. I read the push-button tuning section with interest. I noted that the early models have a different set of momentary switches used than the late models. The ones in the late models have a double row of contacts that allow user choice of how many buttons may be used for AM and FM stations out of the total number of possible push-buttons.

I recently ordered a late model 800B radio/tuner/preamp chassis that includes the wooden front trim panel complete and will have the double row push-button switch contacts.

I am thinking it will be possible to move the newer push-button switch assemblies to the early model chassis which is in better condition overall. It will require some re-wiring to provide the FM common lead to both sides but I think it can be done. Have any of you ever done this?

Joe

[Norman S Braithwaite]

Swapping the push button assemblies would be a substantial endevour.  I do not know of anyone who has tried.  The late version actuated relays that operated the split commutator whereas the early version operated the commutator direct.  The move to used relays was because the tuning motor required more current than the push buttons could reliably handle over long periods of time.

Norman

[Joseph W Strickland]

Norman;

Yes and according to the service manual the contacts in the rear moveable contacts were somewhat stressed by the heavy current too. The FM IF/Audio Out/Power Supply chassis contains the transformer for the motor voltage and current and the later version uses a different voltage motor as well. I imagine the transformer for the late models is different due to the lower voltage of the late version motor.

The contacts of the push-button switch assembly look identical between the two types, but the later unit has an extra contact the early ones do not have.

It may still be possible to do. I have not dug into the details of construction yet.

Joe

[David C. Poland]

I recall when I did an 800B restoration for someone, the changes you describe are effective with serial number 2000.

[Joseph W Strickland]

David;

Thanks for that data point on the early versus late versions. My unit is S/N 1035, so 965 units later the changes were implemented. Do we know what 800B serial numbers are associated with each year of production?

I need to look for date codes on various components to see what the range of component production years is. I was able to date my Hallicrafters SX-25 by doing that plus noting the factory stamped date code on the audio output transformer in it.

I just looked at the radio/tuner/preamp chassis and the push button assemblies can be removed from the chassis be taking out 4 screws plus disconnecting wires to/from the switches. I imagine the late models mount in a similar manner.

Joe

[Norman S Braithwaite]

The full run of 10,000+/- 800B receiver chassis were made between February 1946 and July or August 1947 at which time Scott Radio Laboratories retooled for manufacture of the Metropolitan 16A.  The 800B chassis were stored and retrieved to fill orders.  As evidences by the type of television picture tubes employed in some of the very last 800B radio-tv combinations, it took until 1951 to sell all of the 800B chassis.  Serial Number 2000 would have been built near the end of May 1946.

There should be a final inspection date rubber stamped in the lower left corner of the split commutator shield when viewed from the front of the chassis.  A bright flashlight and rubber neck will help with viewing of this inspection date.  On some sets inspection dates have also been found on the back of the dial plate and on top of the tuning motor (requires removal of tuning motor to examine).

Norman

[Joseph W Strickland]

Norman;

Thanks for information about the inspection stamp. The manufacturing date versus the date placed in a cabinet and sold to a customer could then have considerable variance in a 5 year period.

My friend who owned an 800B years ago had one with the wired remote control. When I worked on it I did not take the wired remote control along for testing. It worked fine when he reconnected it at home. He was the second owner.

I have seen a picture of one 800B with the TV receiver and phonograph combination. It probably took a moving crew to put the set in place in a home.

Joe

[Norman S Braithwaite]

Joe:

With the introduction of the Model 800B, Scott Radio Laboratories sold their models through selected upscale music and furniture stores.  Through these venues, crews were available to deliver and set up the receivers.  Scott 800B receivers equipped with remote keyboards are very scarce.  A post-war remote keyboard (looked identical to pre-war but wired differently) could, of course, be hooked up to any 800B but unless the 800B was set up for the remote, volume control was not possible.  I have parted out one 800B receiver that had been factory modified to also operate the record changer as well as the radio.

Norman

[Joseph W Strickland]

Norman;

The unit that had remote control of the record changer must have been really rare. On the units with remote volume control, I remember dealing with RCA color televisions equipped with remote controls that were made in the 1950s and 1960s. Many of these had relays in the remote circuit that activated up or down windings in the motors that drove the rotation of the controls. RCA was using ultrasonic remote hand transmitter units and receiver units had a microphone element to receive the output signal from the hand unit. There were sets that had a very elaborate remote control system that provided for not only VHF channel change, color intensity and hue plus volume control, but also brightness, contrast and VHF channel fine tuning. Early remotes had tube type ultrasonic circuits in the receiver, but as soon as transistors became available the change to them was implemented.

Most customers were adverse to having long cables running to/from their listening or viewing chair and the receiver. I remember seeing very few custom installations with built-in receivers and remote wiring in the Dallas area where I worked.

Remote control of audio equipment and receivers seemed to disappear for years and eventually became popular again. Most of us now have audio/video equipment with remote controls that allow adjustment of many functions.

Joe

[Thomas Day]

I worked for Heathhkit from 1967 thru 1974 and still have my Heath 21" color TV with remote. It works the same way as the RCA, and in fact is a slightly modified version of RCA's set, complete with RCA picture tube. Sadly, the set started having problems around 1987, and has been in storage since then. Always intended to fix it, but now, not much use. Set is complete with new pix tube, 'table top' cabinet and remote. 

Thom

[Joseph W Strickland]

Today I received a different E H Scott 800B chassis (S/N above 2000) that came complete with the front wood trim panel. The top horizontal piece came loose in shipping, but it should be easy to re-glue it. The cover over the Tuning capacitor is in much better condition than the one that is on my early unit. I plan to move the better cover to my early unit. First it needs some cleaning and polishing. The rest of the 800B I received is not in very great condition. It will be a source of parts for the early unit if needed. This unit does not have the slide rails or the spring latches, so I will still be looking for those.

I am undecided whether to keep the wood trim panel and look for a mahogany cabinet to go with it or to duplicate it in a red oak finish and build a custom cabinet to go with the rest of the furniture in our den.

Joe

[Joseph W Strickland]

Norman;

You wrote, "The late version actuated relays that operated the split commutator whereas the early version operated the commutator direct." As to the relays you mentioned, are they in the late version FM IF/Audio Output/ Power Supply chassis? I looked at the two different radio/tuner/preamp chassis that I have, one being an Early version and the other being a Late one and did not see any extra relays in the radio/tuner/preamp chassis. In the early version radio/tuner/pramp chassis I see two relays, K1 AM-FM Relay and K2 AC Power On-Off Relay. In the Early version FM IF/Audio Output/Power Supply chassis I see K3 Muting Relay and T10 which is the transformer that provides secondary voltages of 24, 36 and 46 VAC @ 2.5A. There are no other relays in my unit. I do not have a Late model FM IF/Audio Output/Power Supply chassis to inspect for a/an extra relay(s).

Joe

[Joseph W Strickland]

I should have looked further. I found extra relays on the Late model schematic of the Pushbutton Tuning System used after SN 2000. The common AC voltage lead to the motor in the Early Pushbutton Tuning System schematic shows the supply voltage is 24VAC, while the Late Pushbutton Tuning System schematic does not state the voltage. I need to check the parts list to see if the two versions use the same motor or different motors. Perhaps the two extra relays are mounted on that rear part of the Radio/Tuner/Preamp chassis where the moveable station contacts are located. I will be taking a closer look tomorrow.

Joe