I have questions about my 7-knob BOL Philly with Robot Control

[Bob Snively]

I am starting this discussion because I have questions about my Philharmonic as I embark on a quest to restore it to optimum performance.

I have included pics of the dial and knobs. 

Other than what I have found on this forum, is there any documented restoration of the robot control? Wiring diagrams or schematics?

Does anyone have any pictures of their push/pull scratch suppressor switch and it's related shaft/knob? Mine has a rotary on/off switch and the knob configuration makes it rather awkward for manual tuning due to its close proximity to the tuning knob.

[David C. Poland]

Other less obvious caps:

The soldered rectangular box below the expander tubes - Replace all 7 of the .5 caps inside with 400 volt or higher volt caps.

And the top left rear rectangular chrome plated tone reactor  (between the 6L7 pair and 6J5 driver pair) has 4 caps inside to replace - failure of these will destroy the bass dual control pot. IMG_1204.JPG  Unsolder the 4 wires - and the 2 chokes inside are a tight fit.

And there is a cap each of the diode modules - f or example:   IMG_1209.JPG   - dismount, also check the resistors and continuity of the coil inside. 

[Brad Winder]

David,

I'm taking notes from this thread; are these capacitor locations documented elsewhere on the site?

[Bob Snively]

David,

   What I found under the chassis is a few replaced caps and a really shiny, looking brand new, soldered capacitor block with what should be 7 of those .5 caps. The amount of work that went into making that box is unreal! 

  Then there's all the original wax capacitors. A strange mix, but I guess the previous owner(s) that worked on it, replaced all the power supply/amplifier caps and pretty much left the receiver alone.

  The picture you included of the diode is helpful, too. There sure is a big voltage divider ceramic adjustable resistor in the upper right corner of that picture!

   Thanks for the heads up on tone reactor
David C. Poland said:

Other less obvious caps:

The soldered rectangular box below the expander tubes - Replace all 7 of the .5 caps inside with 400 volt or higher volt caps.

And the top left rear rectangular chrome plated tone reactor  (between the 6L7 pair and 6J5 driver pair) has 4 caps inside to replace - failure of these will destroy the bass dual control pot. IMG_1204.JPG  Unsolder the 4 wires - and the 2 chokes inside are a tight fit.

And there is a cap each of the diode modules - f or example:   IMG_1209.JPG   - dismount, also check the resistors and continuity of the coil inside. 

[David C. Poland]

That big ceramic resistor with several taps is a replacement for the failed original Candohm, many of which fail over the years. Even if still ok, I replace with expectation of imminent failure. Indeed I had one that initially tested good but failed before I finished replacing caps. The B+ divider segments are 1200, 400, 400 and 2000 ohms to ground.

Cap locations are not so obvious from the circuit diagram. The soldered box of 7 caps is just C51 on the parts list. Some locations are disclosed by the faint dotted line rectangular shapes - shown for the IF transformer and the RF and IF diode assemblies. But not for the bass tone reactor assembly identified as the "Bass Chokes" between the expander 6L7 and 3rd AF tubes. As a teenager, I lucked into the Riders books in a local TV repair shop - and their Philly diagram had handwritten notation that improper expansion and poor performance traced to those 4 caps and I was suffering that and really scratchy bass control too. And then there is one inside the cover over the big tuning cap.

For the early Philly, the treble control was attached to the fidelity-selectivity band spread control. Beginning with the later 1939 upgrade, the treble control was relocated as a separate (7th control) and the scratch suppressor switch under the tuning knob relocated (8th control).

The earliest  Philharmonic used 83V rectifiers, but rather quickly, Scott changed to the 5Z3 like my mid production pointer Philly. Eventually by 1941, the octal 5U4. 

[Bob Snively]

You  are FULL of helpful information! You beat me to my next questions about the the B and C Voltage Dividers resistance measurements. There's a lot to know about these beautiful beasts!

As a note about the rectifiers, this unit has two 5U4's and it's a 7-knob set. 

David C. Poland said:

That big ceramic resistor with several taps is a replacement for the failed original Candohm, many of which fail over the years. Even if still ok, I replace with expectation of imminent failure. Indeed I had one that initially tested good but failed before I finished replacing caps. The B+ divider segments are 1200, 400, 400 and 2000 ohms to ground.

Cap locations are not so obvious from the circuit diagram. The soldered box of 7 caps is just C51 on the parts list. Some locations are disclosed by the faint dotted line rectangular shapes - shown for the IF transformer and the RF and IF diode assemblies. But not for the bass tone reactor assembly identified as the "Bass Chokes" between the expander 6L7 and 3rd AF tubes. As a teenager, I lucked into the Riders books in a local TV repair shop - and their Philly diagram had handwritten notation that improper expansion and poor performance traced to those 4 caps and I was suffering that and really scratchy bass control too. And then there is one inside the cover over the big tuning cap.

For the early Philly, the treble control was attached to the fidelity-selectivity band spread control. Beginning with the later 1939 upgrade, the treble control was relocated as a separate (7th control) and the scratch suppressor switch under the tuning knob relocated (8th control).

The earliest  Philharmonic used 83V rectifiers, but rather quickly, Scott changed to the 5Z3 like my mid production pointer Philly. Eventually by 1941, the octal 5U4. 

[Norman S Braithwaite]

Full Disclosure regarding Philharmonic B+ divider resistors...  There were two versions.  The early divider was 2200-430-420-1200 ohms for a total of 4250 ohms.  The late divider was 2200-430-420-1700 ohms for a total of 4750 ohms.

Norman

[David C. Poland]

Bob - the 5U4 rectifiers suggest you may have a later substituted amp for your 7 knob early BOL Philly.Philharmonic. 

The May 1939 diagram for the 9 knob Philly still shows the 5Z3 tube. The 5U4 is pretty much an octal based 5Z3 so is fine. The October 1939 FM Combo Philly does show use of the 5U4 so maybe switch to 5U4 may  be mid to late 1939.

The revised Phantom Deluxe diagram of Oct 1939 also shows the 5U4 too

[David C. Poland]

Bob - there is a chart of B and C divider information in Riders Volume 14, under Scott - page 14-55.

Also receiver resistance info starts page top of page 14-54. Note that your radio would probably be the "early" figures, in as a much as your radio is essentially a pointer dial model with the 1st iteration of the Stradivarius BOL dial.

I restored a later 9 knob 1940 remote control Philly, and still have a remote control Phantom Deluxe I restored.

Your  remote control radio pre-dates my examples, but I would expect your power switch is on the volume control (rather than on a separate outboard switch for cabinet mounting) and you have a 3rd set cable - being a 4 wire cable from the receiver to a 3rd amp chassis socket. Part of the 24 volt circuit is always "live" in order for the keyboard "volume/on" button to function. Accordingly, the volume control has a power switch that is double pole to both the power up the radio and power up the rest of the 24 volt circuits for the keyboard. And that your amp has a separate smaller 24 volt step down transformer to power the remote control motor circuitry - mounted inside the amp midway on the side apron. 

So, the amp you have probably closely resembles the FM Philly amp diagram on page 14-7 that shows the 24 volt transformer when the remote control option (aka Robot control) is ordered... and 5U4 rectifiers.

Also, you likely have on you amp a head phone jack. As usual, the Scott diagrams omit the head phone jack wiring on the amp diagrams. Expect it to have two positions; partly inserted plug the speaker still plays. Fully inserted, the speaker goes silent. 

[Bob Snively]

David,

  This could explain why nothing happened when I tried the remote. There was no light and no indication of 

of any of its functions were working. I have no 24volt transformer mounted midship under the amplifier chassis and no third set cable. Interesting.

David C. Poland said:

Bob - there is a chart of B and C divider information in Riders Volume 14, under Scott - page 14-55.

Also receiver resistance info starts page top of page 14-54. Note that your radio would probably be the "early" figures, in as a much as your radio is essentially a pointer dial model with the 1st iteration of the Stradivarius BOL dial.

I restored a later 9 knob 1940 remote control Philly, and still have a remote control Phantom Deluxe I restored.

Your  remote control radio pre-dates my examples, but I would expect your power switch is on the volume control (rather than on a separate outboard switch for cabinet mounting) and you have a 3rd set cable - being a 4 wire cable from the receiver to a 3rd amp chassis socket. Part of the 24 volt circuit is always "live" in order for the keyboard "volume/on" button to function. Accordingly, the volume control has a power switch that is double pole to both the power up the radio and power up the rest of the 24 volt circuits for the keyboard. And that your amp has a separate smaller 24 volt step down transformer to power the remote control motor circuitry - mounted inside the amp midway on the side apron. 

So, the amp you have probably closely resembles the FM Philly amp diagram on page 14-7 that shows the 24 volt transformer when the remote control option (aka Robot control) is ordered... and 5U4 rectifiers.

Also, you likely have on you amp a head phone jack. As usual, the Scott diagrams omit the head phone jack wiring on the amp diagrams. Expect it to have two positions; partly inserted plug the speaker still plays. Fully inserted, the speaker goes silent. 

[David C. Poland]

To clarify the amp configuration - one amp 7 pin socket is for the speaker. 2nd socket is also 7 pin  for the main receiver cable. (the pin diameters pin sizes vary to prevent a mix up.) And for a remote control model, a 3rd socket is 4 pin for the receiver's 2nd cable plug. You said your receiver appears complete with regard to the rear housing with presets, the motors and gears. You have the 21 pin Jones socket on the receiver rear apron that fits your keyboard plug.

But your receiver had no 2nd set cable to fit a 3rd amp socket?  IMG_1632.JPG

In truth, I have no experience with the earlier pointer dial era 7 knob remote control Philly. But do for the later 9 knob BOL era remote control Scotts. I assume yours is similar and so:

The proper amp for a remote Philly has a 3rd socket like this for a 4 pin socket:IMG_1042.JPG  This amp photo was during my rebuild. 

The receiver volume control is like this - with 4 lugs for two power switches.IMG_1402.JPG

Your receiver should also have the relay that operates a radio/phono switch wafer - a 3 pole switches-  middle of receiver inside, mounted on the mid chassis center rail that is behind the scratch suppressor switch.

You can add the 24 volt step down transformer - I found one on eBay years ago. The challenge is to mount a 4 bin socket for a matching 4 pin plug. Be difficult to locate period Scott parts. You might be better able to find a later Clinch Jones plug set ( IMG_0528.jpeg )and cable it separately and avoid trying to punch another hole in your amp.

Or - seek a proper Philly amp with the 3rd amp socket intact. Watch Ebay or maybe someone on this web site has one. I believe an old 4 pin tube base from a dud 80 to 5Z3 would suffice as a plug to fit that socket.

[Bob Snively]

David, I misunderstood the third socket/cable. I do have the configuration you are describing with two separate cables that run from the receiver and plug into the amp chassis via the plugs you are describing. My amp has the same holes as the one in your picture.

The receiver chassis has the volume control and the 4-lug on/off switch.

My apologies for the misunderstanding. 

David C. Poland said:

To clarify the amp configuration - one amp 7 pin socket is for the speaker. 2nd socket is also 7 pin  for the main receiver cable. (the pin diameters pin sizes vary to prevent a mix up.) And for a remote control model, a 3rd socket is 4 pin for the receiver's 2nd cable plug. You said your receiver appears complete with regard to the rear housing with presets, the motors and gears. You have the 21 pin Jones socket on the receiver rear apron that fits your keyboard plug.

But your receiver had no 2nd set cable to fit a 3rd amp socket?  IMG_1632.JPG

In truth, I have no experience with the earlier pointer dial era 7 knob remote control Philly. But do for the later 9 knob BOL era remote control Scotts. I assume yours is similar and so:

The proper amp for a remote Philly has a 3rd socket like this for a 4 pin socket:IMG_1042.JPG  This amp photo was during my rebuild. 

The receiver volume control is like this - with 4 lugs for two power switches.IMG_1402.JPG

Your receiver should also have the relay that operates a radio/phono switch wafer - a 3 pole switches-  middle of receiver inside, mounted on the mid chassis center rail that is behind the scratch suppressor switch.

You can add the 24 volt step down transformer - I found one on eBay years ago. The challenge is to mount a 4 bin socket for a matching 4 pin plug. Be difficult to locate period Scott parts. You might be better able to find a later Clinch Jones plug set ( IMG_0528.jpeg )and cable it separately and avoid trying to punch another hole in your amp.

Or - seek a proper Philly amp with the 3rd amp socket intact. Watch Ebay or maybe someone on this web site has one. I believe an old 4 pin tube base from a dud 80 to 5Z3 would suffice as a plug to fit that socket.

[Norman S Braithwaite]

Going from a foggy recollection you will just need to add the 24-volt control transformer inside the power amplifier and run the two 24-volt wires to the two unused lugs on the four pin socket.  The primary of the control transformer connects to the AC line (energized at all times).

Norman