Process

 

After receiving the radio for restoration I use the following process for restoration:

• Examine radio to determine what needs to be ordered:
• Speaker re-cone? Send out if needed
• New tubes? If changing from 6 volt to 12 volt, replace with 12 volt versions
• Electrolytic capacitors
• Paper capacitors
• Resistors?
• Disassemble radio
• Repair selector mechanism
• Ultrasonically clean
• Selector mechanism
• Chassis components
• Faceplate
• knobs
• Refurbish dial
• Clean
• Repaint?
• Electrolytic capacitors re-stuff
• Replace paper capacitors
• Re-stuff vibrator with Aurora Design solid state vibrator
• Replace other components
• If changing from 6 volt to 12 volt, rewind power transformer
• Assemble radio
• Adjust/align/lubricate selector mechanism
• Align radio
• IF transformers
• Oscillator capacitor
• RF capacitor
• Tuning slugs
• Apply reproduced labels as needed/available
• Pack/ship

Sams Photofact SET 229 FOLDER 14

 I scored a Sams Photofact off ebay

Speaker Switch?

 The schematic shows a speaker switch to switch on/off an external rear speaker. I don't see where this is, could it be optional?

Converting From 6 Volt To 12 Volt

 The process I have used in the past is to replace all the tubes with the 12 volt equivalent and rewire the power transformer primary winding for 12 volt. The rewinding is replacing the wire with wire that has 1/2 the cross sectional area and wind twice as many turns to maintain the correct turns ratio. So, if the original wire is 17 AWG and 70 turns, the new winding would be 20 AWG and 140 turns.

One gotcha I have encountered is that the 6C4 tube has no 12 volt equivalent. There are few solutions to this and some research is in order:

1. Pin for pin 12 volt version (most desirable) - Unobtainium
2. Not pin for pin, rewire socket (12BF6)
3. Make an adapter 7 pin to 9 pin and use 1/2 of 12AU7 (µ=17)
4. Replace 7 pin socket with a 9 pin and use 1/2 of a 12AU7
5. Leave two 6 volt tubes and connect their filaments in series (filament currents must be close)

I'll post on antiquesradios.com forum to get more ideas.

Potential equivalents:

EC90
6135
M8080
6100
6AB4
6DR4

Tubes in the radio:

Actual Tube     12 Volt Equiv.

6BA6 (2)          12BA6

6BE6 (1)          12BE6

6AV6 (1)          12AV6

6C4  (1)          ???? <<<<<<<<

6AQ5 (2)          12AQ5

6X4  (1)          12X4

Rewire socket and use a 12BF6 with diode plates grounded????

Filament Currents

6BA6   0.3 A

6BE6   0.3 A

6AV6   0.3 A

6C4    0.15 A

6AQ5   0.45 A    

6X4    0.6 A

https://www.ebay.com/itm/274881427597?hash=item400035b88d:g:BpwAAOSwdYVg~1Sq

https://www.ebay.com/itm/324796545434?hash=item4b9f61f99a:g:ceEAAOSwOQthO3JT

https://www.ebay.com/itm/133882704536?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20140131123730%26meid%3D01aed53859244b11802570b578349254%26pid%3D100167%26rk%3D1%26rkt%3D15%26sd%3D324796545434%26itm%3D133882704536%26pmt%3D0%26noa%3D1%26pg%3D5411%26algv%3DDefaultOrganic%26brand%3DStudebaker&_trksid=p5411.c100167.m2940

It's new home...