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There appear to be at least three versions of the MT-80Z; a board next to a modified MFP-I MicroProfessor board, an integrated board with most MPF-I components still in place, and an integrated board with the MPF-I components re-arranged. The latter is destined 'MT-80AZ The Fox II'. All appear...

Hi, Anyone aware of a TMS7000 assembler that uses the syntax of the original Texas Instruments Assembler? The syntax is well described in the 1989_TI_TMS7000_Family_Data_Manual (original at bitsavers, and a version with bookmarks or proper page numbers at...

Recently I could borrow documentation on the TMS7000 microprocessors and MCU's and related development systems. I intend to scan most of it, as I so far could not find much on the internet. If someone found anything, I could try to avoid duplicate work. Most of the titles: TMS7000 TMS7000...

A long time ago I made a copy of the http://cerealport.homeip.net/cereal/px8/ directory, either from the original or from http://oldcomputers.dyndns.org. Just recently I wanted to unpack all files to see what they contain. The file 'crtforpx.lbr' looked interesting, but it failed unpacking with...

Is there some documentation on PAL/GAL assemblers online? I found a palasm disk set, with promising .PDF files, but these appear to be something else. One can learn a lot from examples and trying, but having some description would be helpful for the current state of the wetware. The attachment...

Hi All, Recently I managed to get the PFBDK sketch from William Cooke working AND have it in a cool case. Currently I am working on extending the code to make it somewhat more flexible and maybe even more convenient. The code is at https://github.com/electrickery/pxdisk_mega, more images are...

After a very long time trying, I finally managed to get my PDP-11/23+ (M8189 plus RAM) working. With working I mean entering programs with ODT and having them work as expected. Usually they just stopped somewhere. The cause appears to be configuring J11 to be grounded and always applying 50Hz to...

After implementing a replacement keyboard for my 80's clone of the Model 1, I also tried it on my Model 4p. It works, so I present it here. Apart from the Arduino Nano, only the MT8816 is somewhat special. It is however cheap and easy to get at the moment. I have no plan to create and sell...

For some time now boards exist to adapt an SMD EEPROM 28C256 part to the cradle found in some Tandy portables. Those cradles are the same as in the PX-4/PX8. With a minor modification, the EEPROM can be programmed with a programmer expecting a DIP-style chip package. Some preliminary information...

The Model 4P has an option to boot from the serial port. The feature appears to be implemented to help testing boards at the factory. It is described in both the Technical Manual and the Service Manual. It it somewhat terse, but with some experimenting it is doable to create a program to make it...

Hi all, If you have problems displaying video from the Model 1 on a (small & cheap) TFT-LCD monitor, here is a description to get the Model 1 very close to the 50Hz PAL standard: https://electrickery.nl/comp/trs80/remarks/TRS-80_Model-1_TFT-monitor_2018-04-06.html . Next to the article are two...

This subject isn't very vintage itself, but it could be useful in repairing vintage hardware. Last week I created a simple TTL-I.C.-logic tester based on an Arduino and a Python script. Currently it only tests 18 different I.C.s from the 7400 series, having 14 and 16 pins. The chip-definition...

I have a TRS-80 Model 2000 with color monitor, two keyboards and lots of docs that is free for shipping costs. The main component missing is the monitor cable. The whole set will fit in two (extended) banana boxes. Beware shipping is not cheap; recently I shipped some boxes with similar weight...

Based om some publications, I tried to recreate 3D-printable mechanical components as they could have been implemented in the Zuse Z1, Z2 and Z4 mechanical programmable calculators (computers according to some). The logic gates were only used in the Z1, but the memory cell was also employed in...

Hi, Recently I aquired a DEC Minc-11, in good shape. Alas not the trolly, but a Minc-11 chassis and a RX-02 cabinet. I cleaned and tested the Minc-11 chassis. The power supply is ok. But when starting it with the cards inserted, it remains in the all LEDs on mode; CPU hung. On inspection the...

Hi, Often people attempt to fix vintage computers with limited knowledge and equipment. Here a relative cheap tool that can help in the process of making a proper diagnostic. If you expect to repair more than one computer, this could be a useful tool. It is based on an Arduino Mega which is...

I spend some time converting a large part of the TRS-80 HACKER'S HANDBOOK FOR NEWDOS/80 by Kevin O'Hare to text format. One goal apart of making a readable version was to get up to date with the NEWDOS/80 internals before trying to disassemble and comment the SYS0/SYS module. The handbook is...

Hi, While scanning the TRS-XENIX System Software Development manual I found that page 9-18 is missing from my copy. If someone might have this page and a scanner nearby, I am very interested on a monochrome 400dpi scan :-) The current result is available in three parts at...

For my AS/400 9402 F02 I am looking for the installation tape with OS/400 V2R2 or similar. The current installation asks for an unknown username/password. I am not interested in any data currently on the system, but just wat a working AS/400. The tapedrive is a QIC-1000, so any tape of that...

For my page on the Epson HX-20 I am looking for information on the origin of this computer. Somewhere on the net I read it was designed in America as were most other computers of that age. Anyone more info on this? http://www.xs4all.nl/~fjkraan/comp/hx20/index.html