Москва-128

[Shockwav3]

6116 always worked fine.
The schematic itself is very strange around KB5-KB9. What device is it? Is there a description?

For testing purposes I'm connecting i.e. KB5 to VCC via a jumperwire.

[Advertiser]

[Serg6845]

For testing purposes I'm connecting i.e. KB5 to VCC via a jumperwire.

looks like databus conflict between D44 and D53 - during keyboard polling they both output something to data bus, but D44 seems to have stronger outputs. maybe you will have to connect D44 outputs to data bus via diodes, like D53, D57 and D58 (or is it D38? scanned schematic is hardly readable)