Elektronika MK-52: The MK-61 big brother?

[jebem]

1) Information on the DC-DC converter internal power supply:
The MK-52 takes the battery supply to generate a number of Negative output supply voltages for the electronics.
The battery Positive terminal is used as Ground as well.

Common:
+BATT/GND (pin9) -> Gnd/+5V to IC's like EEPROM KP1601PP1 Ucc2 pin 24.

Input:
-V1 -BATT (pin7)

Output:
-V2 -15V (pin6) -> IC logic circuits
-V3 -27V (pin5) -> to the VFD display
-V4 -17V (pin8) -> to the -12V regulator for Ucc1 pin 12 and Gnd pin 4 of EEPROM KP1601PP1
-V5 -40V (pin4) -> to the -33V regulator for programming voltage Upr pin 15 of EEPROM KP1601PP1
~V6: 2.4VAC (pin 1 and 3) -> to the VFD display filament [Edit]

Transistors:
VT1: кт361г (KT361G) - PNP Si 250MHz, hfe>50, 35V, 0.05A, 0.15W
VT2: кт315г (KT315G) - NPN Si 250MHz, hfe>50, 35V, 0.1A, 0.15W
VT3: кт626A* (KT626A) - PNP Si, 75MHz, hfe>40, 45V, 1.5A, 6.5W
VT4: кт315г (KT315G) - NPN Si 250MHz, hfe>50, 35V, 0.1A, 0.15W
* Or кт814б (KT814B) - PNP Si, 3MHz, hfe>60, 50V, 3A, 10W

DC-DC Converter diagram:



2) Systemboard main components:

IC's:
D1: К745ИК1302-2 (K745IK1302-2) - Control Unit for Processor, Display and Keyboard;
D2: К745ИК1303-2 (K745IK1303-2) - Arithmetic Processor;
D3: К745ИР2-2 (K745IR2-2) - Memory Registers;
D4: К745ИР2-2 (K745IR2-2) - Memory Registers;
D5: К745ГФ3-2 (K745GF3-2) - Clock Generator.
D6: К745ИК1306-2 (K745IK1306-2) - Additional MK-61 Processor features not present on the B3-34
D7: К745ИК1801-2 (K745IK1801-1) - RAM memory System bus I/O.
D8: КР1601РР1 (KR1601RR1) - EEPROM 1024 x 4 (Eq. to ER2401)
D9: К561ЛА7 (K561LA7) - 4x2 input NAND (like CD4011AE)

Updated: Additional notes on the IC's, by Sergei Frolov:
K745IK130x are same CPU with different firmware.
K745 is a package-less version of K145 ICs.
K745IK1302 is a main CPU (control processor). It organized initialization of serial data ring, keyboard and display controller and perform some operations.
K745ИК1801 is a external I/O controller (Internal EEPROM and External ROM module in MK-52)
K745ИР2 both serial RAM registers.


VFD display:
VL1: ИЛЦ2-12/8Л (ILC2-12/8L or ILZ2-12/8) - Vacuum Fluorescent Display. Filament voltage: 2.15 -2.9 V. Filament current: 20 - 24mA.
Brightness: 700 cd/m^2. Number of digits: 12 (8+2 digit sign).
Size of the digits: 2.4 x 4.3 mm. Color: Green.
Lifetime: more than 10000 hours.

Transistors:
VT1: кт315г (KT315G) - NPN Si 250MHz, hfe>50, 35V, 0.1A, 0.15W
VT2: кт361г (KT361G) - PNP Si 250MHz, hfe>50, 35V, 0.05A, 0.15W
VT3: кт361б (KT361B) - PNP Si 250MHz, hfe>50, 20V, 0.05A, 0.15W
VT4: кт315г (KT315G) - NPN Si 250MHz, hfe>50, 35V, 0.1A, 0.15W



Second set of pictures: