Restoration Of the Standardyne 1928 AC Model Receiver

Standardyne AC-29 radio repair

Author: Edgardo Castro Bruse
Author: YS1ECB
Calle Loma Linda
Residencial Loma Linda casa No. 4
Col. San Benito.
San Salvador. El Salvador.

San Salvador January 15 2016

Standardyne, Model AC-29


It seems to me that my model is an earlier version of the Model AC-29. My model comes with a complete diagram, but it does not show the values for the resistors and condensers of its power supply. There is also a difference in the volume control circuit. Otherwise it is almost identical to the Standardyne AC-29 model.

The outstanding feature of this radio is its wiring that resembles a primitive printed circuit! It uses flat strips of cupper interconnecting the circuit elements. These are held in place by means of rivets with special concave washers that add extra pressure.
the circuit elements

The circuit

This is a regular TRF receiver. Its diagram is self explanatory. I am posting the original diagram that came with the receiver and the diagram for the Standardyne AC-29. You will also find the original diagram with a few modifications and the actual values for voltages and parts. Please click on images to enlarge.
The original diagram that came with the receiver diagram with a few modifications Standardyne original diagram

Power Supply Before Restoration

To renovate the power supply, it was necessary to remove the two filter choques and the condenser block from the metal box filled with Tar! I made a small fire by using a compacted piece of cloth impregnated with thinner, and then I wrapped the box with stiff wire making a kind of a handle. I moved the metal box about the flame keeping it slanted until the tar melted. All of the sudden the contents fell out by gravity!
Power Supply Before Restoration Power supply wiring condenser block Elements removed from a metal box Filter and condensers

Restoration of Power Supply DC Filter

Plastic lace to hold the Choques Filter choques The two choques are connected in series Power Supply DC Filter

Restoration of Power Supply-Voltage Divider

Detector's elements Detector's voltage Restoration of Power Supply-Voltage Divider

Under Chassis Repairs and Data

The wiring is made by using flat copper strips held in place by means of rivets with a special concave washer. This wiring resembles a primitive printed circuit board. Should the need of changing tube sockets, coils and transformers as well as any of the resistors arise. The task to do this job would be very difficult. Luckily I did not have to do any of this.
Filament bypass condenser Jumpers to restore continuity to the filament of a 226 tube RF by pass Capacitor
Chassis elements Chassis

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