Original colors were found as the damaged finish was stripped off. 

Stain colors were custom blended to match what was found under the original lacquer

Multiple coats of high gloss lacquer applied.  About 7 coats. 

A PM speaker replaced the open field coil electrodynamic speaker. 

Flat rubber washers were used to better set the chassis height.

This cabinet will be stripped and refinished.

All the parts are included except one knob.  I think one control shaft was cut off to remove the chassis. 

All coils and IF transformers ohmed out good. 

I need the schematic to confirm what this is.  It may be a bias cell. I can measure about 168 mv on it. Tracing the circuit will tell for sure what it is. 

This disk is driven from the tuning shaft.  It needs replaced. 

Audio output transformer tested good. 

The black donut surrounded by the brown "U" bracket is the field coil. 

I will follow the lead wires into the coil.  Maybe there is an accessible break in the wire. 

Unless an electrodynamics speaker economically  becomes available, I think we will go with a permanent magnet speaker and a 1500 high wattage ceramic resistor for the old field coil. Permanent magnets were hard and expensive to come by in the 1930s.  I will mount the audio output transformer on an open space on the chassis. 

Chassis component locations. Green tested good. This should help me determine the model number. 

Cost estimates are coming in for rewinding the field coil.  There is no easy way to separate the coil from the frame.  It needs to be cut and welded back together.  All that labor on top of shipping, and rewinding costs make repair of the original speaker a poor economic choice.  Replacement is more cost effective.  If this was a classis stand a lone speaker like this one, then the cost may be well worth it.  But this is a common speaker concealed in the cabinet. The search goes on. 

0.49 or 1/2 inch thick

0.80 inches wide.

20.32 mm

12.5 mm thick

High voltage lug missing and a bit of carbon on the chassis.

Epoxy and a new lug. 

A before shot showing the new HV solder lug. 

This is a dead dry cell.  It provided negative grid voltage for the #75 tube.

  It is made of Unobtainium. 

A quick trip to RadioShack to find a 1.5 volt lithium cell that fits inside the battery holder.

Wrap it in heat shrink and trim it neat.

The positive outer shell will not short to the old battery holder. 

That's slick baby!  This should last a long time.  But it will eventually need replacement.  

The grid circuit draws about 134ma. (as calculated from the voltage drop on the series resistor).  

When the battery runs down the audio will get distorted.  Measure the voltage across the battery clip with a volt meter.  If it is less than 1.0 volts it is time for a new battery.  It is best to use a battery tester that applies a proper load. 

All components have been replaced.  All but the parts on order, Tone control and Volume on/off control.  The bias battery is easily accessible in the middle of the chassis. 

This tone control is jammed, will not rotate and is burned. 

What is the minimum wattage needed for the 50k ohm tone control?  I think is is a wire wound.  The rated output of the 6B5 is 4 watts.  Only a part of that will go through the tone rheostat due to the series capacitor.  So logically something less than 4 watts is needed.

The research came back at a 1/2 watt.  Quite available.  the Xc of the capacitor with the tone control near full bass is about 650 ohm with the 0.05 capacitor from plate to ground.  Good. I have a half watt long shaft on order.   Xc= 1/(2*3.141*R*C) C farads R ohms

Determine the radius.

Razor on 3/4 plywood. 

Just high enough to score the plastic.  Use multiple rotations. 

Move the disk for the inner hole. Remember Measure twice & cut once.

This is the second try. The first disk's inner hold was too big and the brass mounting ring was too small. I could not successfully heat expand the ring.  

The brass retaining ring was opened up a bit with a Dremel tool and epoxy in place. 

The retainer still needed press fitting. 

Tuning knob shaft edge drive. 

This clear plastic disk, driven by the tuning knob, moves the air capacitor veins (tuning capacitor) and the dial pointer. 

Align and paint the indicator.  See the "Dial Scales" page for a high res scan of this dial scale. 

Before.

        After with flash.  Three colors of tint was  used to match the original colors.  The colors were carefully chosen to both match the original hue and allow the grain to show through.  The black highlight was one of the colors.  About 7 coats of lacquer have been applied. The wood was stripped and sanded.  

Nice new reproduction grill cloth. 

I just need to get the proper size knob in.  The upper right is just a tad too big.  Good for tuning bad for the match. 

No flash. 

See the PM speaker.  A 1500 ohm 10 watt wire wound resistor has been installed to replace the voice coil.