01-09-2021, 04:51 PM
Here's an update on this one. This is how it finally ended up looking. The color is a little off it's under fluorescent light. Oh and those knobs cost me $50 I just happened to find them on ebay.
And here's the circuit mods. (This is one messy looking schematic even before I scribbled all over it.)
First of all it's a farm radio 6 volts DC. I am thinking how to power up this beast. The vibrator is no good. First I tried cleaning the contacts but to no avail.
Next I am thinking to build a switching unit to replace the vibrator. But this still needs a power supply.
Then it occurred to me why do I need a switcher when I want to run the radio on 120vac. What if I put 6vac to the primary of the step up transformer and see what comes out. And this worked, in fact it worked too well. (And this is with a small 1.5 amp filament transformer). So I added a dropping resistor to keep the B+ voltage down. It went on the 120vac side of things. I also added two diodes to the secondary side to take the place of the switching of the vibrator.
Next I added a bridge rectifier for the filaments and a dc to dc boost to run a string of LEDs for the dial. It had no dial light.
And lastly tried a string of Zenners for a high voltage clamp while the tubes warm up. It worked like a charm. I hope they don't ever burn out. I know this is living dangerous. Now it's works pretty well. It's amazing how little power it needs.
And here's the circuit mods. (This is one messy looking schematic even before I scribbled all over it.)
First of all it's a farm radio 6 volts DC. I am thinking how to power up this beast. The vibrator is no good. First I tried cleaning the contacts but to no avail.
Next I am thinking to build a switching unit to replace the vibrator. But this still needs a power supply.
Then it occurred to me why do I need a switcher when I want to run the radio on 120vac. What if I put 6vac to the primary of the step up transformer and see what comes out. And this worked, in fact it worked too well. (And this is with a small 1.5 amp filament transformer). So I added a dropping resistor to keep the B+ voltage down. It went on the 120vac side of things. I also added two diodes to the secondary side to take the place of the switching of the vibrator.
Next I added a bridge rectifier for the filaments and a dc to dc boost to run a string of LEDs for the dial. It had no dial light.
And lastly tried a string of Zenners for a high voltage clamp while the tubes warm up. It worked like a charm. I hope they don't ever burn out. I know this is living dangerous. Now it's works pretty well. It's amazing how little power it needs.
!!!!!!!!!!!!!!!!!!!RESISTANCE IS FUTILE!!!!!!!!!!!!!!!!!!!!!!
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[Image: http://philcoradio.com/phorum/images/smi...on_eek.gif] Chris
