RetroFuture Vacuum Tube Multimedia Player - Bluetooth Tube Radio Project #7

This is the latest work of my Bluetooth tube radio projects, but it is not only a "Bluetooth radio" or "Bluetooth Speaker".

This set has color display, stereophonic tube amplifier and speakers, and DVD drive. Furthermore it can play thousands of network contents.

Step 1:

Originally this is a tube MW radio set. It was made in Japan in 1950s .
TV Broadcasting in Japan had just began in late 1950s , and stereophonic audio systems placed on the Japanese market around the same time, but ordinary people of defeated nation could not afford such luxury products. So in 1950s, MW radio sets still was a star of entertainment. Japanese living room of those days needed massive and gorgeous radio sets. This set would accommodate such demands. As you can see, this set has HUGE center window and symmetrically placed speaker grills. These must have been designed in tribute to Television sets and stereos. But sadly enough, center window only shows tuning status, and one of two speaker grills is dummy.

Step 2: Build a Stereo From a Stereo-like-looking 1 - Cut Out the Other Hole

First ,disassemble the old set.
There is only one speaker in the left side of cabinet. In spite of such symmetrical looking, there are not any speakers behind the right side speaker grill.There is only a wooden board without any holes So for the first step we will cut out another speaker hole

Remove the old grill cloth and cut out the same shape of the hole for speaker on the other side.

Step 3: Build a Tube Stereo Amplifier on the 5 Tubes Superhet's Chassis

Now we will make 2-channel tube amplifier and place control knobs on the original chassis.
First replace all sockets and power transformer.

Step 4: Place Parts and Wire

Adding a new speaker unit on the right side of cabinet, there is no room for output transformers on the chassis, so place them beneath the chassis.

Step 5: Wire Patiently

wiring is done

Step 6: Open the Front Window

Cut out the center window carefully with a thin-blade saw.

Make a trim and set it for old TV looking.

The offcut window will be used as a cover for screen.

Step 7: Place LCD and Test It

Place the LCD panel.

This time I selected the 7inch LCD panel with driver board

Connect Raspberry PI and DVD drive with self-powered USB hub.

Then test it.

Step 8: Control Panel

Originally there are three control knobs on the front panel.
The left knob is the selector for radio and phono, The center and right knobs are for volume and tuning .

As a controller for multimedia player, it needs functions like mouse or joystick . So I assigned one of three to cursor control and the other two to push buttons.

At first, I intended to substitute rotary encoders built in switches for push button, but its feeling is not good, so I tore them and assembled with micro switches.

Step 9: Connect Controller Module

Take out the control module from junk membrane keyboard
As its name suggests, there are two sheets of silicon membrane placed beneath the keyboard. Under the every key there are pair of electrodes on the membranes placed face-to-face. Each electrodes connect one of 28(14+14) electrodes of control module. Each key is identified by permutation of 14*2 electrodes. If you need to emulate particular key with mechanical switches, trace the electrodes on membranes to discover the permutation of 14 and 14 electrodes and check again with a tester.