Электроника МС 0511 (Elektronika MS 0511): Part 4
25Progress ... it boots! Maybe a video RAM issue now ... ?
As @jasonbirch6450 commented in the last video, 7W has to be going somewhere.
So I left it running a bit longer today - still, couldn't find anything above ambient (so, nothing was running) on the main board.
I then planned to remove the network interface card and accidentally felt a warm patch on it ... it was only slightly warmer because the power had been off for a little while, but it stood out.
Turns out there is a K155ЛА18 (K155LA18, equiv. to a Texas Instruments SN75452 dual-channel driver) that was hitting about 50ºC. Removed the network interface card and the machine booted!
To garbage.
I connected up the keyboard and started pressing some keys ... pressing [УСТ], [ПОМ] and [ИСП] got some text!
As per @Mercury13kiev's earlier comments:
[УСТ] = Set
[ПОМ] = Help (?)
[ИСП] = Exec (?)
Pressing the number keys changed the highlighted text so the machine is working! Just maybe an issue with the Video RAM?
The machine uses the usual КР565РУ5 (KR565RU5, equiv. to 4164) 64Kbit DRAM ... 24 of them, making 192KB in total.
As per the Wikipedia article:
https://ru.wikipedia.org/wiki/Электроника_МС_0511
The 192KB of RAM is split as below - guess I'll need to check the schematic to determine which 12 chips are relevant (on the board there's two rows of 12 so maybe just one row then?):
CPU memory: 64 KB
Software memory: 32 KB
Video memory: 96 KB (3 blocks of 32 KB)
УКНЦ