Multitech: Micro-Professor III

complete_box

I got this interesting Apple //e (64k) clone from a friend in Norway recently. When he got this at first time it was unopened and not used, all new. So it’s almost in new condition, used maybe 2-3 hours max. It came with seemingly as the day it came from the factory in Taiwan.

Multitech had released several models for it’s “MicroProfessor” line already before MPF-III.

-MPF-1 that was very simple programming learning “oneboard”-machine
-MPF-II almost Apple II compatible, with it’s own software but also hobbyists modified Apple II software for it.
-MPF-III that had two different models released, 310/311/312 and 327 that used MMU and ASIC chips as Apple //e did. According to info found on wed it had 128k RAM onboard making it real Apple //e compatible.

All these models were sold in Finland but MPF-II seems to be most “common” out of these.

Multitech became more known company called ACER in 1987.

box

The box. Seems they had modified the 310 model to 312 model. Wonder what’s the difference? 

serials_in_box

Box serial numbers are matching to hardware inside.

 

box_opened

Everything as it was new.

front

Out of the box then… front of the unit. It’s very slim as there’s no traditional vertical slots in this model. There is one expansion slot in side of the unit like vTech Laser 128 or CEC-E.

back

In back, there’s two floppy (20pin) connectors, microphone, earphones, switches for setting up the printers, printer connector, volume, ext. speaker, monitor, TV and power. Luckily the power supply installed had 115/230v switch on it.

right_side

In right side there’s keyboard and joystick connectors as well the regular Apple II slot expansion for additional Apple II bus card.

 

main_logic_board_edit_s

The main logic board is quite interesting… 

1) Floppy disk controller card
2) Z-80 CP/M Processor card
3) Video circuit board
4) Connector for optional Chinese Character Generator card 

video_rom_and_ram

The video ROM and the main RAM are under the video circuits card.

rom

The ROM’s.

 

ad_for_mpf3

Original advertisement for the MPF-III

 

mpf_iii_dual_floppy_drive

They also sold neat double froppy drive enclosure for the MPF-III. I’d like to get one of these!

 

slot_extender_s

There were also similar to Laser 128, external slot extender box to give more slots.

 

mpf-iii-board-layout_s

The manual have the main logic board layout pictured with chips info.

Technical specifications of MPF-III/312

Made by : Multitech / Taïwan
Released : 1983
Keyboard: 90 key, full stroke, internal conductive rubber membrane, 12+ function keys, numeric keypad
Processor : 6502P
Speed : 1MHz
RAM : 64KB DRAM + 2KB SRAM 
ROM : 24 KB
Text modes : 40 x 24 / 80 x 24
Graphics models : 40 x 40-48 (16 col), 280 x 160-192 (6 col), 560 x 160-192 (2 col)
Colors : 16 
Sound :1 bit Apple II compatible + AY-3-8912 Programmable Sound Generator.
I/O : TV RF out, Monitor Out, External Speaker Out, Cassette In/Out, Printer (16 pin), Keyboard, Joystick, External (Slot 2, Apple II compatible).
Power supply : Internal switch-mode, PS-007, AC INPUT 87 – 135V or 185-265V 47-67Hz, with switch between 110/230V.

The internal slots are configured as follows:

1 (virtual) Built-in Parallel Printer port – support for Epson, C-Itoh and CP-80 printers
2 (external) Accepts standard Apple II cards (on right side of the machine)
3 (virtual) Built-in 80 Column Card – Apple IIe compatible
4 (internal) Reserved for optional Chinese Character Generator card (EMPTY)
5 (non-existent)
6 (internal) Reserved for optional Floppy Disk Interface (INSTALLED)
7 (internal) Reserved for optional Z-80 CP/M card (INSTALLED)

I tried few cards with the expansion slot (2), but could not get Fastchip //e or Booti card work. Also the ProDOS 2.4.2 or 2.5.x did not load up. I think it might have crashed when ProDOS tries to create .RAM drive as the machine completely halted. I found some comments about this from the web:

ProDOS did not work (unpatched) on the MPF-III/312 for two reasons:
1) Apple put a test in the ProDOS initialization code that looks for the string APPLE in the monitor ROM. The MPF-III ROMs did not have this string. A one byte patch to the PRODOS file fixed this.

2) The Apple IIe came in 3 memory configurations – 64KB, 65KB (with 80 column text card) and 128KB  (with 64KB 80 column card). ProDOS checks for more than 1KB of Aux RAM and if it finds it, sets up a 64KB RAMdisk. The MPF-III/312 has 66KB which ProDOS takes to be 128KB and attempts to create the /RAM drive. Again, a simple patch to ProDOS fixes this.

I thought this was handled by ProDOS 2.4.2 already – but i informed John Brooks that heads the development of the ProDOS 2.5 about this.

apple_ii_mode

wDrive worked nicely. The keyboard is… well, kind of strange. It have quite light weight touch when typing, kind of similar as with Laser 128. I have one of these keyboard for my BOSS-1 clone, but it’s Finnish/Swedish layout localized. It also reads “Multitech”.

 

cpm_mode

CP/M loaded up as well.

ram_errors_s

But… then my fun playing and testing with the MPF-III ended with odd problems the unit started to have. It would crash occationally, freeze or then just would not load up anything enymore. There’s built-in hardware test that tests the RAM, ROM, Soundchip and Colors and it started to give odd errors for the RAM… I assume it’s the power supply. It would really need a repair as it havent been used for … 36 years so or. I dont seem to have similar power supply that i could swap in. The clones often had different connectors and order of pins/voltages.. I really need to open up that power supply and see what’s going on and if i am able to do anything to fix it.

To be continued….

FinApple 2020 (c)
Apple II Forever.