WR1/T RESTORATION WORK
 

We're currently in the process of restoring the WR1-T entertainment radio. The task is made difficult by the general lack of accessibility of most internal components. We are trying to avoid completely dismantling this receiver. The top section of the radio is the power supply, which allows the use of batteries or various levels of utility power. 4 capacitors in this section were bad and had to be replaced. The original capacitors were carefully opened, and new capacitors were inserted inside, soldered to the connectors, and carefully sealed to preserve original appearance. When I received this radio, two of the seven tubes in it were bad. I have ordered these tubes and will have to wait until they are delivered to test the actual radio portion of this receiver.

We were not able to replace all of the failed tubes with originals. So, based on Vladimir Dvorkin's expert advice, we reconfigured Raytheon 1AD4 sub-miniature vacuum tubes into their German Wehrmacht equivalents. The general procedure is shown below in photographs. The WR1/T worked beautifully with the new "ersatz" vacuum tubes. Now all we needed was portable power.

The WR1/T was designed to receive power from various sources of electricity. The switch on the right center of the console (shown below) allowed the receiver to be switched from utility to battery power. The utility-power system of the WR1/T was "transformer-less", which means that it just uses a huge selenium rectifier and large capacitors to turn AC into internal DC. This is an outdated and dangerous design which subjects the user to potential high voltage shock. In light of this, we decided to supply the WR1/T with simulated battery power. In other words, we would create two power supplies; one for the Anode voltage, one for the Heater voltage, and we would place them in the battery compartments. Carefully hidden power cables will provide AC power to both power supplies, and DC power from the power supplies to the WR1/T.

The power source setting switch.

The Anode power supply (90 V) would come from an existing commercial Accopian 120 V power supply, fitted with additional resistance on the output which would bring the voltage down to 90 V. This Accopian power unit fitted perfectly into the top Anode battery compartment.

The Heater (filament) power supply was more of a complex matter. It had to be built from scratch. Again, Vlad Dvorkin assisted us with a schematic, and a voltage regulator chip that stabilizes the output voltage of this power supply no matter how the input voltage changes. This power supply generated two 1.25 Volt DC outputs, simulating two Heater batteries, as the original configuration required two Heater batteries.

The WR1/T as seen before any restoration or repair. This is how I've received it.
 
Here we're testing the original rectifier of this radio. It is bad and produces only 70% of the necessary DC current.
 
Here we attach a modern rectifier diode to the power leads of the radio. The result is close to perfect.
 
Here is a picture of a period capacitor.
 
Here you can see two period capacitors in the background, and a comparable modern one in the bottom left part of the picture. Nice size difference.
 
In the dungeon: my father reading over the instruction manual.
 
This is a photo from the underside of the WR1/T. This shows the radio receiver mechanics and some of the radio circuitry.
 
The PCB being drawn based on design plans.
 
Here we are making a PCB for the Heater Voltage power supply. The board is currently being immersed in PCB etching solution. Very toxic!!!
The PCB after the etching process. The hand-finishing work.
 
The drill press used to create the PCB component holes.
The finished PCB
The finished heater power supply. It has two 1.25 Volt outputs for a total of 2.5 Volts. Several vacuum tubes in this radio use 1.25 Volts on the + Heater and some use 2.5 volts. This power supply acts like two heater-voltage batteries. Totally custom-made for this radio, and it even has fuse protection.
This here is a Raytheon 1AD4 sub-miniature vacuum tube - a pentode. This is a very common American tube made in very large numbers and are very easy to find, unlike the WR1-T vacuum tubes which are a very rare set. We will configure these 1AD4 tubes into a Wehrmacht DF11 body. The setup will be called "a pentode configured into a triode pinout".
First, we open a bad DF11 tube and clean out the insides - quite a labor-intensive effort.
View of the DF11 from above.
Then we insulate the pins and connect them according to the pinout configuration of both the 1AD4 and the DF11 tube.
Then we drill ventilation holes in the DF11 cap, re-crimp the cap back into place, solder the connectors, and voila........a DF11 tube comes back to life with American tubes.
Here is the WR1/T with half of the Wehrmacht tubes re-done with American 1AD4 tubes.
 
Here is the modified Accopian power supply providing 90V to the original Anode battery + and - termini.
Here is the filament voltage power supply with a piece cardboard separating the connector plate from the chassis of the power supply.
These wires lead to the two power supplies inside the battery cases and to the power switch inside the lower box. All of this has been added without ANY modification to the wooden radio box or the actual WR1/T receiver. All of this can be removed easily. This WR1/T easily plugs into a wall outlet with a standard computer cable that can be taken out of the internal socket inside the lower cable compartment.
Here is a home-brewed main power switch and plug that I attached inside the power cable compartment. This is a regular computer cable that can be removed from the plug at any time. The on/off switch is the main switch between the utility power and the receiver.
The WR1/T after the repair. The original power cord has also been repaired, and would supply power to the receiver.

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