38-116 Restoration - Printable Version
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RE: 38-116 Restoration - rfeenstra - 01-17-2020
I printed the station tabs in the previous photo on ordinary photo paper. I need to find some printable, translucent material to print the tabs. The photo paper is very readable in normal light but not very translucent. When the "magnetic tuning" is ON, the tabs are supposed to be backlit by 2 lamps reflecting off from a reflector ring, the light passing through the shadow mask and the tuning dial before lighting the back of the tabs - not very effective, especially with the tabs printed on paper. So, a new, easily removable backlight system has been incorporated. I had a circuit board made that incorporates 16 LED's that is powered by the 6.3 volts from the magnetic tuning lighting system.
The second photo indicates that half the LED's are dead. Not really! The LED's are powered from the AC voltage from the filament supply. 2 are in series that will light on the positive half of the AC, while the next 2 are series to light on the negative half of the AC . The LED's actually alternately flash on and off at 30 cycles per second. My shutter was set at 1/125 so it caught only half of the LED's lit. I do the alternating routine to reduce the apparent 30 cycle flicker. Next is a photo at 1/30. I thought that was interesting, but maybe it's only me!
Here's the system installed in the autotune system. It is in the space between the band selector shadow mask and the tuning dial.
RE: 38-116 Restoration - rfeenstra - 01-17-2020
And now, the final results (in the dark).
RE: 38-116 Restoration - Jake Blake - 01-17-2020
Mmmmmmmmmmmmmmmmm....LOVE those dial lights and warm-colored dials!!! Thanks for sharing.
RE: 38-116 Restoration - rfeenstra - 01-21-2020
I had mentioned in a previous post that hardware rubber washers I used in the tuning capacitor coupler were just a bit too flexible and allowed for a bit of hysteresis when zeroing in on a station. That has now been solved. I was able to find 1/8" rubber that is reinforced with 2 layers of fabric as the originals were.Works great.
RE: 38-116 Restoration - mikethedruid - 01-21-2020
Where did you find that rubber? It might be useful for others who encounter a similar situation?
RE: 38-116 Restoration - rfeenstra - 01-21-2020
I purchased a sheet of it on line from Home Depot.
https://www.homedepot.com/p/Rubber-Cal-Cloth-Inserted-SBR-1-8-in-x-24-in-x-12-in-70A-Rubber-Sheet-Black-20-107-0125-24-012/303197202
Very flexible but not as stretchy as just rubber.
RE: 38-116 Restoration - Nicko - 02-02-2020
Very nice job! I to will be restoring my 38-116 soon. The station tabs look amazing with the led light ring behind them. Did you have any extra circuit boards printed for making that light ring? What a slick idea.
RE: 38-116 Restoration - klondike98 - 02-02-2020
Great job!
RE: 38-116 Restoration - rfeenstra - 02-16-2020
Been out of town for a couple of weeks - trying to enjoy sun and heat. But, happy to be back to the cold!
Nicko, I had several made as there was a minimum. Soldering the surface mount LED's is a bit of a trick but doable. I made a couple more as I will use one for the 37-116 a finished a year or so ago, and one for the 37-116 that is waiting to be restored.
By the way, welcome to the phorum!! I missed it the last couple of weeks. One gets addicted.
Rob
RE: 38-116 Restoration - quick573 - 01-10-2021
Its internally grounded..Ohm it out.
RE: 38-116 Restoration - rfeenstra - 01-10-2021
Thanks, Quick573. If I ever take this radio out of the cabinet, I will ohm it out. I have just never seen that in a control like this. But then, I'm not all that experienced with these.
RE: 38-116 Restoration - Tim Tress - 01-22-2021
Nice work on the restoration! Yes, the ground connection is carried to the frame of the control, so it is grounded through the bushing; that saved one wire on the assembly.
I have my own 38-116 restoration to get back on; I either need to find another speaker for it, or have it reconed.