![🇹🇼 Multitech Micro Professor MPF-III: Part 4 (Keyboard Protocol) [#TCE0699] @Brfff](https://i.ytimg.com/vi/rif3yqV77Lc/maxresdefault.jpg)
Uploaded June 2026 | Updated September 2026, 3 weeks ago
Ad-free version on my Patreon ... patreon.com/TheCluelessEngineer
Finally, some progress on reverse engineering the keyboard and its serial bus protocol!
The MPF-III is Multitech's Apple IIe clone, a further development of their MPF-II Apple ][ clone. It has a separate keyboard, which my machine is missing ...
The first issue was getting past the cyclic self-test. This was caused by the missing keyboard, more specifically the PB1 signal (similar to the Apple ]['s "Closed Apple"?) not being pulled low on boot. Once this was held low the machine booted into BASIC.
After a few tests of different combinations of AKD (any key down), DATA, CLOCK and STROBE we finally figured out how to get the letter "A" (code 0xC1) to print on the screen!
Essentially:
[1] AKD goes high when the keyboard sends the scan code byte;
[2] DATA sends one bit at a time, LSB first;
[3] CLOCK pulses eight times, one for each bit; and
[4] STROBE pulses when the byte has been sent.
All the details are on my Github:
github.com/BrettHallen/MicroProfessor
00:00 ... Intro
03:00 ... Recap on the behaviour with no keyboard
06:15 ... Getting into BASIC finally
08:30 ... Testing various combinations
09:20 ... SUCCESS ... printing "A"
10:05 ... The protocol
12:25 ... Channel thanks & outro
--------------------------------
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you don't think it's worth it, then cancel ... no hard feelings ... I appreciate any support, even if it's just subscribing to my YouTube channel!
patreon.com/TheCluelessEngineer
--------------------------------
Outro music: "Diamond Eye" (White Bat XXX) by Karl Casey @ White Bat Audio
karlcasey.bandcamp.com
youtube.com/@WhiteBatAudio
Ad-free version on my Patreon ... patreon.com/TheCluelessEngineer
Finally, some progress on reverse engineering the keyboard and its serial bus protocol!
The MPF-III is Multitech's Apple IIe clone, a further development of their MPF-II Apple ][ clone. It has a separate keyboard, which my machine is missing ...
The first issue was getting past the cyclic self-test. This was caused by the missing keyboard, more specifically the PB1 signal (similar to the Apple ]['s "Closed Apple"?) not being pulled low on boot. Once this was held low the machine booted into BASIC.
After a few tests of different combinations of AKD (any key down), DATA, CLOCK and STROBE we finally figured out how to get the letter "A" (code 0xC1) to print on the screen!
Essentially:
[1] AKD goes high when the keyboard sends the scan code byte;
[2] DATA sends one bit at a time, LSB first;
[3] CLOCK pulses eight times, one for each bit; and
[4] STROBE pulses when the byte has been sent.
All the details are on my Github:
github.com/BrettHallen/MicroProfessor
00:00 ... Intro
03:00 ... Recap on the behaviour with no keyboard
06:15 ... Getting into BASIC finally
08:30 ... Testing various combinations
09:20 ... SUCCESS ... printing "A"
10:05 ... The protocol
12:25 ... Channel thanks & outro
--------------------------------
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you don't think it's worth it, then cancel ... no hard feelings ... I appreciate any support, even if it's just subscribing to my YouTube channel!
patreon.com/TheCluelessEngineer
--------------------------------
Outro music: "Diamond Eye" (White Bat XXX) by Karl Casey @ White Bat Audio
karlcasey.bandcamp.com
youtube.com/@WhiteBatAudio
![🇹🇼 Multitech Micro Professor MPF-III: Part 4 (Keyboard Protocol) [#TCE0699]](https://i.ytimg.com/vi/rif3yqV77Lc/mqdefault.jpg "🇹🇼 Multitech Micro Professor MPF-III: Part 4 (Keyboard Protocol) [#TCE0699]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Finally, some progress on reverse engineering the keyboard and its serial bus protocol!
The MPF-III is Multitechs Apple IIe clone, a further development of their MPF-II Apple ][ clone. It has a separate keyboard, which my machine is missing ...
The first issue was getting past the cyclic self-test. This was caused by the missing keyboard, more specifically the PB1 signal (similar to the Apple ][s Closed Apple?) not being pulled low on boot. Once this was held low the machine booted into BASIC.
After a few tests of different combinations of AKD (any key down), DATA, CLOCK and STROBE we finally figured out how to get the letter A (code 0xC1) to print on the screen!
Essentially:
[1] AKD goes high when the keyboard sends the scan code byte;
[2] DATA sends one bit at a time, LSB first;
[3] CLOCK pulses eight times, one for each bit; and
[4] STROBE pulses when the byte has been sent.
All the details are on my Github:
https://github.com/BrettHallen/MicroProfessor
00:00 ... Intro
03:00 ... Recap on the behaviour with no keyboard
06:15 ... Getting into BASIC finally
08:30 ... Testing various combinations
09:20 ... SUCCESS ... printing A
10:05 ... The protocol
12:25 ... Channel thanks & outro
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Outro music: Diamond Eye (White Bat XXX) by Karl Casey @ White Bat Audio
https://karlcasey.bandcamp.com
https://www.youtube.com/@WhiteBatAudio")
![🏴 ESP32 Rainbow (ZX Spectrum Emulator): Part 1 (First Look) [#TCE0713]](https://i.ytimg.com/vi/rukjT8Spwzc/mqdefault.jpg "🏴 ESP32 Rainbow (ZX Spectrum Emulator): Part 1 (First Look) [#TCE0713]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Im not really interested in software emulation but I thought this looked really neat ... a Speccy 48/128 emulator running on an ESP32-S3 incorporated into a single board computer (SBC) layout from Chris Greening aka @atomic14.
It includes the screen, speaker and separate headphone jack, USB-C power and Micro SD card slot. It also has three additional expansion interfaces (a 2x9 pin header and two QWIIC ports). Its fully open source (see links below) and can also be purchased fully assembled.
The assembled computer cost US$99 (plus US$18 shipping to Australia and US$11.70 GST) which came out to about AU$185. I was pretty impressed by how fast it got to me - ordered on Sat 8/8, shipped Thur 13/8 (by Mouser via UPS) and delivered Fri 14/8.
Assembled board ordered from: (🇺🇸)
https://www.crowdsupply.com/atomic14/esp32-rainbow
Website: (🇬🇧)
https://www.esp32rainbow.com
But does it run Doom?
https://youtu.be/xxxroEjTqFQ
Open Source Emulator for ESP32:
https://github.com/atomic14/esp32-zxspectrum
Based on the OpenVegaPlus emulator:
https://github.com/alvaroalea/OpenVegaPlus
Open Source Hardware:
https://github.com/atomic14/esp32-zxspectrum-hardware
Marsmare: Alienation download: (🇷🇺)
https://rgb.yandex.ru/2020
Drunk Fly website: (🇬🇧🇷🇺)
https://www.drunkfly.eu/en/marsmare-alienation
Nunchuck as Kempston joystick:
https://github.com/atomic14/esp32-zxspectrum/issues/5#issuecomment-3071196051
3D printable case designs:
https://github.com/atomic14/esp32-zxspectrum/discussions/17
00:00 ... Intro
05:30 ... Power on
09:00 ... Loading TZX file from SD card
10:00 ... Trying Marsmare: Alienation
15:30 ... Channel thanks & outro
Check out my Patreon for ad-free and in-progress videos and coming soon updates between videos - there is a free membership tier for the coming soon updates and various paid tiers (from US$2). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer")
![🇯🇵 National ナショナル CF-3000 MSX Computer: Part 3 (HDMI Upgrade 2/2) [#TCE0703]](https://i.ytimg.com/vi/tPIYgKeyNGs/mqdefault.jpg "🇯🇵 National ナショナル CF-3000 MSX Computer: Part 3 (HDMI Upgrade 2/2) [#TCE0703]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets finish off the HDMI upgrade by properly installing the HDMI output board ... with audio this time.
There was a suitable location on the motherboard that was perfect for the board. I also found a suitable location on the motherboard for a hole to thread the audio cable from the AV board underneath.
Did a test by running ARKANOID and using my Clueless Joypad for MSX.
00:00 ... Intro
01:45 ... Audio cable routing
05:20 ... Holes drilled
08:00 ... HDMI board mounted
09:15 ... Testing ARKANOID
11:30 ... Further plans
12:20 ... Channel thanks & outro
From Part 2:
Lets upgrade the video output to HDMI by replacing the TMS9928 with a Pico9918. There is definitely a marked improvement over the composite video output - we load Boulder Dash and play a level to compare.
Pico9918 on Github:
https://github.com/visrealm/pico9918
Regarding the CN4 2x17 connector, the consensus (from Part 1) is that its for the floppy disk controller PCB that is installed in the CF-3300 ... somewhere.
Future plans are to replace the 100VAC power supply with a 12VDC universal power supply and pull the keyboard apart to discern its matrix so I can design a replacement for machines that are sans keyboard.
If I wasnt going to install the Pico9918 then I would also design some sort of RGB21-to-VGA converter.
There is a service manual/schematic available for the related CF-2700 (export CF-2000?) but its not exactly the same - more relevant to the CF-2000 model.
From Part 1:
Lets have a look at the interesting component system style MSX1 computer from National or ナショナル. Its the big brother to the CF-2000 (traditional all-in-one) and fraternal twin to the CF-3300 that includes a 3½ floppy drive & 2nd drive interface.
Its a pretty standard MSX1 computer:
- Z80 CPU with 64KB of RAM
- TMS9928 VDP with 16KB of VRAM
- two cartridge slots
- two DE9 MSX joystick ports
- 8-pin DIN cassette port
- composite video & audio output
- RGB21 video output (SCART-like connector but not SCART pinout)
- Printer port (Centronics)
- Superimpose (スーパーインポーズ) port for the CF-2601 Superimposition Unit
- 100VAC passthrough for CF-2601
The Superimposition Unit would connect via the dedicated Centronics connector and allow you to overlay ... superimpose ... computer graphics on to NTSC video. A pretty rare unit these days I imagine.
The keyboard connects via a 2x10 pin header so a reproduction could be designed and connected relatively easily ... much easier than if it had some sort of exotic 14-pin DIN port, for example.
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Outro music: Somewhere In Time (White Bat 49) by Karl Casey @ White Bat Audio
https://karlcasey.bandcamp.com
https://www.youtube.com/@WhiteBatAudio")
![🇨🇳 TP-Link Tapo P110 Smart Plug: Part 2 (Serial Debug Interface) [#TCE0683]](https://i.ytimg.com/vi/ueGAsRGw82Y/mqdefault.jpg "🇨🇳 TP-Link Tapo P110 Smart Plug: Part 2 (Serial Debug Interface) [#TCE0683]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets have a look at the serial debug logs from the Realtek RTL8710CF microcontroller - Im using an Arduino Mega 2560 as it has several hardware serial ports ... one port from MCU and one port to my computer. You could also use a 3.3V TTL to USB dongle as well.
Part 1 video here:
https://youtu.be/b5snm9TfyWc
As the Realtek is a 3.3V device I am powering it via the Arduinos 3.3V output. There is no issue to receive serial from 3.3V-to-5V, but to send commands to the Tapo MCU I used a simple voltage divider to drop the 5V level: a 1KΩ resistor between Arduino TX and Tapo MCU RX and a 2.2KΩ pulldown resistor to ground.
I could get the boot up logs which showed it connecting to my WiFi network that it remembered from when it worked. I could get the help command to list out some WLAN commands, such as ATWS to scan WiFi networks, but it wouldnt accept it, so some further investigation is needed there.
WLAN AT COMMAND SET:
1. Wlan Scan for Network Access Point
# ATWS
2. Connect to an AES AP
# ATW0=SSID
# ATW1=PASSPHRASE
# ATWC
3. Create an AES AP
# ATW3=SSID
# ATW4=PASSPHRASE
# ATW5=CHANNEL
# ATWA
4. Ping
# ATWI=xxx.xxx.xxx.xxx
[MEM] After do cmd, available heap 29688
I could also trigger an image download mode by pulling test point TP2 high (3.3V) when booting:
Rtl8710c IoT Platform
Chip VID: 5, Ver: 3
ROM Version: v3.0
Test Mode: boot_cfg1=0x20
Download Image over UART2[tx=16,rx=15] baud=115200
All the info is on my Github here:
https://github.com/BrettHallen/TP-Link_Tapo_P110
00:00 ... Intro
01:55 ... Arduino setup
04:09 ... Serial port interaction
09:35 ... Channel thanks & outro
From Part 1:
One of my TP-Link Tapo P110 smart switches failed (see below) so I pulled it apart some time ago. I wasnt really planning a full teardown ... I decided today that I wanted to design my own simple, local-network-only replacement and was curious how they managed the AC-to-DC conversion as Im accustomed to vintage computers with massive transformers, diodes, capacitors and a hot-running linear regulator.
We use these devices to control lights (turn on/off automatically in the evening & randomly when were away) and for the pool pump when the solar panels are generating power (save me walking outside to do it manually) ... neither of these tasks really require phoning home to China.
Im happy to just configure via a local web interface and then forget, hence why I want to work on my own. Im pretty happy with how my Router Rebooter [#TCE0678] is working so want to invent more.
Sure, its no doubt already been done far better than I could, but I learn more designing it myself, including all the mistakes.
It looks like the main chips are:
- Shanghai Belling BL0937 energy meter that measures RMS current & voltage, etc.
- Realtek RTL8710CF microcontroller on a daughterboard labelled KB-6160 and ZSL-1
- Silergy SY22841 buck regulator (labelled ZRxyz) to convert AC to DC (?)
Its also got a pair of Churod A1-S-105IA2F relays with 5V coil to switch the active/neutral lines.
The microcontroller daughterboard has 12 connections, labelled P1 to P12, to the main board as well as six Test Points:
- TP1 = ?
- TP2 = pull high to trigger image download
- TP3 = 3.3V (P2)
- TP4 = GND (P12)
- TP5 = serial receive
- TP6 = serial transmit (115200 bps, 8 data/no parity/1 stop bit 8N1)
Regarding the failure ... it looks like a 470µF capacitor failed. It had a slight bulge in the lid and measured at less than 1nF (i.e. nothing). A shame that the device is NOT repairable ... well, by me at least ... I made a right mess trying to get it open.
My Router Rebooter Github:
https://github.com/BrettHallen/Router-Rebooter
https://youtu.be/Fz1aSylL9KQ
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Background music:
Nocturne No. 2 in E Flat Major Op.9 no.2 by 🇵🇱 Frédéric Chopin
https://www.classicals.de
Publisher: Musopen Kickstarter Recording Project - Set Chopin Free
Copyright: Creative Commons - Public Domain Mark 1.0 Universal")
![🇯🇵 National ナショナル CF-3000 MSX Computer: Part 2 (HDMI Upgrade 1/2) [#TCE0701]](https://i.ytimg.com/vi/vbAl0F2aXNE/mqdefault.jpg "🇯🇵 National ナショナル CF-3000 MSX Computer: Part 2 (HDMI Upgrade 1/2) [#TCE0701]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets upgrade the video output to HDMI by replacing the TMS9928 with a Pico9918. There is definitely a marked improvement over the composite video output - we load Boulder Dash and play a level to compare.
Pico9918 on Github:
https://github.com/visrealm/pico9918
Regarding the CN4 2x17 connector, the consensus (from Part 1) is that its for the floppy disk controller PCB that is installed in the CF-3300 ... somewhere.
Future plans are to replace the 100VAC power supply with a 12VDC universal power supply and pull the keyboard apart to discern its matrix so I can design a replacement for machines that are sans keyboard.
If I wasnt going to install the Pico9918 then I would also design some sort of RGB21-to-VGA converter.
There is a service manual/schematic available for the related CF-2700 (export CF-2000?) but its not exactly the same - more relevant to the CF-2000 model.
00:00 ... Intro
01:45 ... Motherboard removal
02:15 ... Japanese power supply
04:55 ... TMS9928 removed
06:10 ... Boulder Dash via composite (TMS9928)
09:30 ... Pico9918 output options
12:00 ... Boulder Dash via HDMI (Pico9918)
16:20 ... HDMI mounting options
17:55 ... Channel thanks & outro
From Part 1:
Lets have a look at the interesting component system style MSX1 computer from National or ナショナル. Its the big brother to the CF-2000 (traditional all-in-one) and fraternal twin to the CF-3300 that includes a 3½ floppy drive & 2nd drive interface.
Its a pretty standard MSX1 computer:
- Z80 CPU with 64KB of RAM
- TMS9928 VDP with 16KB of VRAM
- two cartridge slots
- two DE9 MSX joystick ports
- 8-pin DIN cassette port
- composite video & audio output
- RGB21 video output (SCART-like connector but not SCART pinout)
- Printer port (Centronics)
- Superimpose (スーパーインポーズ) port for the CF-2601 Superimposition Unit
- 100VAC passthrough for CF-2601
The Superimposition Unit would connect via the dedicated Centronics connector and allow you to overlay ... superimpose ... computer graphics on to NTSC video. A pretty rare unit these days I imagine.
The keyboard connects via a 2x10 pin header so a reproduction could be designed and connected relatively easily ... much easier than if it had some sort of exotic 14-pin DIN port, for example.
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Outro music: Delta City (White Bat 42) by Karl Casey @ White Bat Audio
https://karlcasey.bandcamp.com
https://www.youtube.com/@WhiteBatAudio")
![🇯🇵 Sanyo PHC-30N MSX Computer: Part 2 (Pico9918 Installation & Keyboard Clean) [#TCE0686]](https://i.ytimg.com/vi/wInAnoi41x8/mqdefault.jpg "🇯🇵 Sanyo PHC-30N MSX Computer: Part 2 (Pico9918 Installation & Keyboard Clean) [#TCE0686]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets give the keyboard of this 1984 MSX1 computer from 三洋 Sanyo a good clean/refurbish and replace the composite video output of the TMS9118 VDP with crisp RGB/VGA output from a Pico9918.
My Github:
https://github.com/BrettHallen/Sanyo_PHC-30_MSX_Computer
Pico9918 details:
https://www.tindie.com/products/visrealm/pico9918-pro/
https://github.com/visrealm/pico9918
{Regarding issue with the Pico9918 & warm reset via RESET button: it might be an issue with the Sanyo itself, rather than the Pico9918 ... need to test further}
00:00 ... Intro
02:45 ... Keyboard plate resprayed
03:25 ... Keyboard Rebuild Tunes
05:55 ... Rebuild completed
06:45 ... Key switch orientation
08:35 ... New power supply plans
09:35 ... Pico9918 vs TMS9118
11:35 ... TMS9118 removed
12:55 ... Ready to test
14:35 ... TMS9118 vs. Pico9918
16:40 ... ひらがな and カタカナ (thanks to @JonCo)
18:00 ... Channel thanks & outro
From Part 1:
https://youtu.be/X6lxfxol4aE
Lets have a look at 三洋 Sanyos 1984 MSX computer, in a rather striking red colour, the PHC-30N. This machine has 64KB of RAM compared with the earlier PHC-30 (1983) with only 16KB of RAM.
This is my first MSX computer so all quite new to me. As these machines were fairly standardised it has a Z80 CPU, 64KB of RAM, 32KB ROM, and a TMS9118 VDP and 16KB of dedicated video RAM (in a pair of TMS4416 , 16K x 1-bit).
The Japanese 100VAC power supply generates ±12VDC and +5VDC. It looks like +12VDC is used by the data recorder in some fashion, and I guess the ±12VDC is made available for cartridge use (RS232 interface?).
It might be possible to power the machine with +5VDC only, i.e. via a USB charger, if I wanted to forgo anything that needs ±12VDC. Lets see.
My plans are:
[1] Scrub the case & keyboard;
[2] Try the Pico9918 in place of the TMS9118;
[3] Figure out how to replace the Japanese 100VAC power supply;
[4] See if I can add an audio input to the data recorder so I can load digitised tapes;
[5] Check out what home brew cartridge designs there are;
[6] Test my Clueless Joypad in MSX mode.
Main parts list:
- Sharp LH0080A Z80 CPU
- Fujitsu MB64H120 gate array
- Mitsubishi M5L8255AP-5 peripheral interface (PPI)
- Hitachi HN613256P 32Kbit ROM (mask code Y00)
- General Instruments AY-3-8910 Programmable Sound Generator (PSG)
- 8 x Fujitsu MB8264A-15 64K x 1-bit main DRAM
- TI TMS9118NL Video Display Processor (VDP)
- 2 x TI TMS4416-20NL 16K x 4-bit video DRAM
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Background music:
Nocturne No. 2 in E Flat Major Op.9 no.2 by 🇵🇱 Frédéric Chopin
https://www.classicals.de
Publisher: Musopen Kickstarter Recording Project - Set Chopin Free
Copyright: Creative Commons - Public Domain Mark 1.0 Universal")
![🇯🇵 National ナショナル JR-200: Part 1 (First Look) [#TCE0695]](https://i.ytimg.com/vi/wLMDZcOQIaI/mqdefault.jpg "🇯🇵 National ナショナル JR-200: Part 1 (First Look) [#TCE0695]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets have a look at this MC6802-based computer, released in 1982, from Matsushita in Japan. Unfortunately it seems to be faulty so well work on that in Part 2 after giving it a bit of a clean.
It was also sold as the Panasonic JR-200U (North America) and the JR-200UP (PAL) in Europe. It succeeded the JR-100 and preceded the JR-300.
This machine is from Japan so requires 100VAC (were 240VAC here in Australia) so will need a step-down transformer. But it might be possible to convert by swapping the transformer (100-to-21V).
Its main chips are:
- MN1800A CPU (an MC6802 minus the clock generator & with the internal RAM disabled ... so, like an MC6800?)
- HD61K201F CRT (plus other things) controller
- MN1271 I/O interface (equivalent to two 6522 VIAs?)
- MN1544CJR 4-bit microprocessor for the keyboard & joystick I/O
Ignoring the CPU, its a bit of an odd machine ... it has 32KBytes of RAM implemented as four 4864 64Kbit DRAMs ... 4-bit RAM? There is 4KByte of video RAM (two 6116 SRAM) which would be faster as its 8-bit ... ?
It has a screen resolution of 256x192 pixels and a text screen size of 32x24 in eight colours.
It has a good array of ports:
- two MSX-compatible joystick ports
- RCA jack for 8Ω speaker (there is also an internal speaker)
- 8-pin DIN for cassette (seems a little excessive)
- 8-pin DIN for RGB and composite video
- Printer port
- System bus expansion port
- Space for an RS232 port
The composite video output can be switched between colour (カラー) and monochrome/B&W (モノクロ) and the cassette can be switched between 600 & 2400 Baud.
Some good information here:
http://www.kameli.net/marq/?page_id=1270
https://github.com/ypsitau/jr200
https://github.com/0cjs/sedoc/tree/main/8bit/jr-200
00:00 ... Intro
01:45 ... External ports
04:50 ... Testing composite video output (NOK)
06:50 ... Opening the case
09:00 ... Keyboard
10:35 ... Motherboard
13:15 ... Closer look
15:30 ... Channel thanks & outro
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Outro music: Lexicon (White Bat 40) by Karl Casey @ White Bat Audio
https://karlcasey.bandcamp.com
https://www.youtube.com/@WhiteBatAudio")
![🇷🇺 Sura PC8000 (Сура ПК8000): Part 1 (First Look) [#TCE0690]](https://i.ytimg.com/vi/wWDCWSeaxUg/mqdefault.jpg "🇷🇺 Sura PC8000 (Сура ПК8000): Part 1 (First Look) [#TCE0690]
Ad-free version on my Patreon ... https://www.patreon.com/TheCluelessEngineer
Lets have a look at this ... inspired by MSX ... computer from the Soviet Union, specifically the Russian SFSR. Unfortunately this one isnt working ... the 220VAC power supply is making a horrible whining sound ... more info below ... likely all of those beautiful electrolytic capacitors have probably failed.
The MSX was apparently imported in the late 80s and used in education. An attempt was made to reproduce a domestic version but it simply wasnt possible with the available Soviet technology at the time.
One major difference is the use of the КР580ВМ80А, the Soviets clone of the Intel 8080, and not the Z80. I believe it was kind-of compatible in BASIC but that was about it. It also uses the Soviet-era JCUKEN keyboard layout, not QWERTY.
This particular model was built in 1989 and sold for 1035 Soviet Rubles (maybe just over four months salary at the time).
There were other versions produced by other factories called:
- Веста (Vesta)
- Хобби (Hobby)
- Карат (Carat)
The PSU is supposed to generate +5VDC and ±12VDC but doesnt appear to be doing do ... it also needs -5VDC for the КР580ВМ80А (Intel 8080A clone) which it generates from the -12V and +5V rails. Im thinking that I will repurpose the replacement PSU I designed for the Sanyo PHC-30N so I can run it on just +12VDC (will add to my Github).
It doesnt have dual cartridge ports but has dual DD50-like ports ... X1 and X2 ... theyre not truly DD50 as theyre using Soviet 2.5mm pin pitch.
More information can be found here:
https://pk8000.narod.ru/
https://ru.wikipedia.org/wiki/ПК8000
And I will put information on my Github here:
https://github.com/BrettHallen/Sura_PC8000
00:00 ... Intro
03:30 ... Information plate
04:30 ... Ports
06:20 ... Opening the case
11:40 ... Removing the daughterboard
13:55 ... Heat sinks?
14:35 ... Video pinout
17:00 ... Power on attempt (NOK)
18:35 ... Wheres the -5VDC for the 8080?
22:00 ... Channel thanks & outro
Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you dont think its worth it, then cancel ... no hard feelings ... I appreciate any support, even if its just subscribing to my YouTube channel!
https://www.patreon.com/TheCluelessEngineer
Outro music:
Sunshine Drive
https://youtu.be/HBQbFCq-G2E
Lavaros @LavarosMusic
https://lavaros.bandcamp.com")
![🇬🇧 Psion Organiser: Part 2 (Comparing the Organiser I & Organiser II) [#TCE0527]](https://i.ytimg.com/vi/wuXOnCx6u9I/mqdefault.jpg "🇬🇧 Psion Organiser: Part 2 (Comparing the Organiser I & Organiser II) [#TCE0527]
🇬🇧 Psion Organiser: Part 2 (Comparing the Organiser I & Organiser II) [#TCE0527]")
![🇦🇺 Breville BSK500 Kitchen Scale Teardown [#TCE0500]](https://i.ytimg.com/vi/yDk3B_En0bc/mqdefault.jpg "🇦🇺 Breville BSK500 Kitchen Scale Teardown [#TCE0500]
🇦🇺 Breville BSK500 Kitchen Scale Teardown [#TCE0500]")
