This power unit can be used to work with radio stations R 105 - P109, RD - RD, RM - RM.
In the device used unified transformer TN-220/127-50 (you can use any with the allowable current of the secondary winding of at least 1 and a voltage of at least 4-5 In). Four existing filament winding are switched by two in parallel. The primary winding is included in its entirety, to reduce the voltage on the secondary winding.
Rectifiers are collected in a bridge circuit diodes CDV. You can use any of the diodes with the allowable current of at least 1 A. Capacity included after the rectifier, must be at least 4000,0 UF (C50-16). Actually the stabilizer is assembled according to the standard scheme ("Radio", 12/84, pp. 44-45) transistors CT and KT3102 and resistant to overloads and short circuits. Resistors R4, R7 set the output voltage of each shoulder without load 2.5 to 2.6 V. as Zener VD9 - 2 VD1 you can use any silicon diodes, for example, CDA.
The output of the stabilizer installed capacitor of not less than 2000,0 UF. Zener VD13, VD14 (triggering) are chosen so that:
Uвых.St-Thor - Uвх.St-Thor < Uстаб.St-throne < Uвх.St-Thor
Instead CT you can use a compound KT818 + CT, including between the base and the more powerful emitter of the transistor by a resistor 100 to 300 Ohms.
The power unit was installed in the battery compartment of the radio station: the transformer and the diode bridge and the lower compartment, and the electrolytic capacitors and stabilizers in the upper part. Regulating transistors mounted on a small heat sinks (6 × 10 cm) aluminum reclining rear wall of the station.
This power unit is used with the radio M, rebuilt to work 29FM (NBFM), and when the output voltage of ±2.5 V delivers a load current of 1 A at a voltage ripple <5 mV.
Author: A. Sheaves, Saratov, Russia; Publication: N. Bolshakov, rf.atnn.ru