🇷🇺 Партнер 01.01 (Partner): Part 11 (Video Tweaks & Loading Games) [TCE #0486]
34A bit of a long one ... I dawdle around trying to improve the video output (I think I did, slightly). But I also figured out how to load software properly. Duh.
For the video changes I made:
[1] Inductor (choke) L1 (дроссель 1П5.752.040, labelled "ДПМ 0.1-040-А8") looked to have some damage so I replaced it from the spare motherboard I have ... no idea how to source an equivalent part in the West ... apparently it's a ДПМ-type, nominal inductance 40µH, maximum constant current 100mA (0.1A)
[2] There was an additional (and undocumented) 330Ω resistor connected to ground in parallel with R30 ... removed it as it was not on the 2nd motherboard I've got either
[3] Replaced R31 (apparently 1.2KΩ but actually only 51Ω) with a 75Ω resistor to impedance match the video input
For loading code, there's two ways on the Partner:
[1] if the file is in "MSX format" (I think) ... it has a header ... then you use the [R] command in the Monitor and, optionally, specify the filename (or just enter [/P]), or
[2] if the file is straight data (no header) then load the file like on the RK using the [I] command.
Interestingly the screen goes blank when loading via the Monitor [I] command ... like on the ZX81.
I managed to load something called RIKT, XONIX (a game like QIX) and PACMAN.
The XONIX version I loaded is apparently for the МЦПГ (MCPG) colour module.
@MrWaalkmansuggested trying the casutils program that comes with mame for converting RKP files to WAV - seems to do the job!
From the TPP2 keyboard test program I found that my left arrow key isn't working properly, so I'll need to look at that.
More details about the Partner can be found here:
https://github.com/alemorf/retro_computers/tree/master/Partner_01_01
... or here (with OCR'd text):
https://archive.org/details/partner-01-01-documentation
From the Part 1 video:
It's a machine built in 1990 and looks to be quite well made with a magnetic reed-switch keyboard (more about that in a future video). It's actually based on the Radio 86RK (Радио 86РК) homebrew/DIY computer.
Incredibly easy to get into, to pull apart, clean and to service - keyboard, motherboard and PSU all unplug from each other.
Nice.
The machine has three 27C64A EPROMs and four cloned Intel chips:
КР580ВМ80А (KR580VM80A) = Intel 8080 clone
КР580ВВ55А (KR580VV55A) = Intel 8255 clone (PPI)
КР508ВТ57 (KR508VT57) = Intel 8257 clone (DMA controller)
КР580ВГ75 (KR580VG75) = Intel 8275 clone (CRTC)
On the left side it has a cassette port (МАГ), a video output (ТВ) and I assume a +5VDC output (+5В).
On the right side it looks to have a home-made joystick port - a DIN socket (surprise!) that is connected to the cursor keys on the keyboard.