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Computer "Byte" is made on a similar principle as original ZX-Spectrum, so there are two lines of RAM. One line 16K at 8 chips 4116 (russian analogue KR565RU6) (Address #4000- #7FFF, slow memory), the second line - 64K at 4164 (russian analogue KR565RU5) (Address #8000- #FFFF, fast memory).
In "old" version of the computer RAM permormed at chips KR565RU5D1 or KR565RU5D2. This defective chips 4164, which is working only half of the chip. At the time, the production of memory chips in the USSR was very expensive, so even defective chips as possible allowed to use the equipment. In KR565RU5D1 (D2) chips was OK, only one half of the memory cell. Thus the capacity of the chip is only 32 kilobits.
Often, instead of line 4116 installed 4164 chips, which facilitate RAM uprade to 128K.
When repairing a computer when it is necessary to change the broken RAM chips, they can not be put on the sockets, because it increases the height of the chip and the computer unit can not be closed.