Trio AD-5 3-Tube FM Multiplex Adapter

Description

I purchased this off eBay and found a few things wrong with it: it was missing the tubes (12AX7, 6AU6, 12DW7), the power indicator bulb had opened up, and it looked like someone had taken a pair of pliers to the four OA79 diodes. (!) I added the three tubes, replaced the diodes, and converted the power indicator to an LED. As you can see from the photos, the 19KC oscillator works well. And that's as far as I can take it, as I do not have a 19KC FM multiplex signal to feed it to see if it works. I also could not find a schematic for it; however, the power supply looks to be a very nice and ripple-free 180 volts DC on my 'scope, so the power supply components are in good shape. The original power indicator incandescent lamp was connected to the AC line through the power switch; after removing the defective bulb, I added a diode, dropping resistor and LED to the same circuit, which works well but may be a tad dangerous - you may want to tap off the filament supply with your own LED circuit for "Power On" indication. In any case, this unit looks like it was well designed and rugged; the components (resistors & capacitors) all checked ok. I replaced the input RCA with a gold-plated unit on the back. There is an extra set of jacks on the back marked "Inputs A & B" which probably correspond to the selector switch position called "Stereo Monitor". Not sure what the noise filter or the "Dimension" pot does. What you see in the pictures is what you get - there is no case, nor are there feet.
Selling as “For parts or not working” because I cannot check its operation.