Sintez was a Soviet clone of ZX Spectrum manufactured in today’s Moldova.
This computer has original Sintez-M case and keyboard. Internals look like some DIY version of ZX Spectrum and are not from Sintez. Computer outputs correct RGB video signal, but with weird 70 Hz vertical and 23 kHz horizontal sync frequencies. CPU shows signs of life and ROM seems to be coming from ZX Spectrum. I could not connect it to any monitor that would accept these video signal parameters.
Composite Video Signal Board
This keyboard only looks like ZX Spectrum+ keyboard. It is of a completely different construction and is made from much worse quality plastic.