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

[jebem]

As I mentioned above, I couldn't find schematics with power supply waveforms; however, I have published my own scope reading from my working calculator.

Attached is the schematic diagram in good readable condition.

Also, as long as one can read/learn a little of Russian language (or just use Google translator for that matter), there is a excellent public domain book in djvu format, describing these Russian calculators in detail.
For example, the MK-52 power supply operation is described at pages 83 an 84.

ПРОГРАММИРУЕМЫЕ МИКРОКАЛЬКУЛЯТОРЫ Устройство и пользование, Под редакцией Я. К. ТРОХИМЕНКО, МОСКВА «РАДИО И СВЯЗЬ», 1990.
(Programmable micro-calculator - Design and operation, published by J. K. Trohimenko, MOSCOW RADIO AND COMMUNICATIONS 1990)

The above book url points to the well known site of Eugene Troitskiy at www.emulator3000.org.