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]

Good that you do have the properly configured amp. Agree with Norman. 

As per the amp diagram for the FM combination Philly Riders 14-7 -  The wiring for the "Robot control" for your receiver:   the 2 smaller socket holes #1 & #4 carry one side of the  115 house voltage to the receiver's power switch and back to the amp to primary of the power transformer. The 2 large holes #2 & #3  are available to connect the both sides of the 24 volt line to the receiver. Trace your 4 wire cable wiring to be sure your 1938 radio wiring conforms to this 1940 diagram.

You sure you do not have the separate small size 24 volt step down transformer in your amp?  Look for 4 small unused holes on the amp side apron, opposite the 4 pin socket. On my amps, these holes were for mounting the 24 volt step down transformer. If you do have that transformer, then trace wiring lest your power switch on the volume control is faulty to explain a failure to power up. With the set plugged into to house and the radio is "off",  the 24 volt line should be "live" at the receiver power switch ...  and be present at the 21 pin set socket for the 3 wires to the volume up and volume down buttons only. 

Suggest you Post a bottom view of your amp.

Note that a 5 amp fuse is proper for your Philharmonic.

[David C. Poland]

I note the 3 topside filter caps are replacements. They appear post war and maybe new enough to still be decent.

The originals were taller and different construction.

example:  24 volt step down transformer:  $24  eBay item number:236618369445

[Bob Snively]

Thank you. 

Norman S Braithwaite said:

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

[Scott Seickel]

The later amps all had the 4 pin socket.  You can tell the later amps by the 3 filter capacitors in a row, whereas the early amps had 4 that are in a diamond pattern. What Norman said, 2 of those pins are for the ON/OFF switch, and the other pair are for 24 VAC for the remote.  They only installed the transformer if the set was a remote, otherwise the extra 2 pins were not used.  

I saw mention of the B+ divider.  It is common to replace these with an Ohmite 50 watt resistor with adjustable taps.  If you need the part numbers for the replacement, let me know.  

So far, I have not run into a C divider that was bad.  The B dividers are nearly always bad, at least one section is open. 

Here is your transformer wiring.  Pretty straightforward.  

[Bob Snively]

Scott, your schematic is beautiful! Do you have the entire power supply/amplifier unit schematic available? Any parts list for same?  Thank you.

[Scott Seickel]

I sent you a friend request. 

Bob Snively said:

Scott, your schematic is beautiful! Do you have the entire power supply/amplifier unit schematic available? Any parts list for same?  Thank you.

[Bob Snively]

Thanks, Scott. I accepted your friend request.

[Bob Snively]

As I am going through the controls on the front of the receiver chassis, I notice my wave range switch (band selector) front bearing plate has been jacked with probably due to it's stiff nature. After a thorough cleaning, minor straightening of the outer front portion of the plate, I am still having an irregular feel for the detents. Is there anything I can do for this other than find a good working replacement from another Philly? If so, how difficult would it be to locate one? 

[David C. Poland]

Band switch should not be stiff. pretty simple if all the parts are there. Lubrication issue? 

[Scott Seickel]

I might have a detent plate available if you can't get that one to work properly.  I would have to go thru my boxes of parts.  I have many dial pointer parts available.