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Interesting read! I am trained as a software engineer in the 80's and started programming with Pascal. I had a Model 4 by then and used Pascal80 for the programming I did at home (the university had an DEC VAX). Good to read the humble beginnings of Tiny Pascal, I wish I had access to Byte in...

Python was developed in the late 80's at the CWI in The Netherlands, its first release was Python 0.9.0 in 1991. This was well after the heights of the Z80 so no contemporary Python implementation for the TRS-80 has ever existed. There are a few lightweight implementations as PyMite and...

Thanks! I cleaned the inside and the PC-1500 is still working. The PC-2 needs the same treatment but it doesn't work at the moment. Hope this helps!

I recently dug up my small collection of Pocket Computers and checked my 2 PC-2's and the Sharp PC-1500A. I have a rather complete selection with the Printer/Plotter, Cassette interface, RS-232 interface and a 4K, 8K and 16K ram module. After opening up the PC-1500 and one of the PC-2's I found...

Ok, that was quick. I found a picture of the same power supply in good order. So C2 is 0.22 µF and C1 (next to the fuse) is 0.1 µF. Both > 250v. See picture! I bought some for my Model 4 which seem usable for my Model II as well, these are Wima MKP-X2 275 V/AC, both 0.22 µF and 0.1 µF Bart

I got a Model II with the Astec AA11081 power supply, which I recently disassembled since the capacitors did blow up. It has a C1 and C2 of different size, see picture. Do you know the value of these as well? The Tech Manual has a schematic of the AA11080 but no values. Regards, Bart

For those interested in this board, maybe even for reproducing it, I've uploaded the pictures of front and back. The chips are readable this time😊

Being a Tandy collector I recently ran into an IBM PC XT with 640Kb, full height 5 1/4" floppy and a full height 5 1/4" Miniscribe hard disk. The machine did start up but wouldn't boot from the HDD. I was able to enter ROM Basic. I don't have any PC-DOS or MS-DOS diskette lying around anymore so...

A small celebration today, on this day in 1977 Radio Shack introduced the TRS-80 to the public in the Warwick Hotel in NY. The first introduction was overseen by the press, largely by a bomb alarm in a nearby premise, but after a few days the word spread and Tandy was flooded with questions and...

I'm interested in several Model I ROM versions for a small article that will appear in a few weeks time. Doing my research I stumbled on the Level I ROM for the Model III that has been retrieved somewhere in 2009 by David Cooper (Marmotking). Does anyone know about this ROM and where I could...

I'm trying to debug a bootloader for a Model 4 OS that works fine in an emulator but not on the real hardware. That is to say, it does do what it is supposed to do but I can't get the display right. The message "Loader version 0.3" is displayed in the middle of the screen, approximately on row...

Thanks for the pointers, especially the article in 80-Micro was helpful. I found a small modification and a trace cut underneath Z34, which is the (empty) ROM socket. There are two wires, the same type as used for the lower case modification, so I'm pretty sure that reversing the mod is easy...

A few months ago I received a slightly battered Model 1 with a lot of satellite boards and modifications (lowercase, Level II board, new character generator, connector for external keyboard) and also an satellite board with four chips and two switches from "Mumford Micro" (a company still in...

Ok, I got some progress! The character generator rom appears to be a 2716 and its contents have been dumped. The board is marked Nenijwa which is/was a Dutch company selling supplies and parts for the TRS-80 in the eighties. So the character ROM was a commercially available product, although the...

I think Tom is right and the text is MEMORY SIZE, thus an older Rom. It's an older M1 with the two roms and Level II on a satellite board. The character generator is from unknown origin as I just recently bought the M1. It's on the other satellite board with the blue ribbon. It's probably not...

All, I got this modified M1 and I tried to bring it back to life and remove some of the odd modifications such as an connector for an external keyboard. One modification is still in place which is a new character rom. The M1 boots but then shows two errors: - many characters are replaced by a...

I have a M4P and a M4, both are 64k machines. For a special project I need one of them to be 128k, preferably the M4. As far as I know both of them are Non-GA's but I'm not quite sure if this differs, and how to be 100% sure. What is needed to do the upgrade, apart from the 4164 chips? Bart

(English) Dutch TRS-80 User Group - archive online and new website. The Dutch TRS-80 User Group has been established on 1 October 1978 to support the new Home Computer from Tandy, the TRS-80. The User Group made a quick start and grew to over 4000 members. It published a bi-monthly newsletter...

I created a small bootable kernel for my M4P with SDCC which I managed to squeeze in an empty JV3-file. It works fine on an emulator (SDLTRS on my Mac) and now I want to move it over to my 'real' M4P. I have a FreHD but since my JV3 obviously has no file system I can't use DSK/DCT. Also I don't...

The Personal Computer That Beat Apple (For a While) Bart