Hello from the past!

About some devices and programs which I developed for the HP-41 in the early eighties.

First of all: I am German and apologize for my bad English.

How it began.

Some years ago - it was in the summer of 1980 ;) - I bought my first HP41C and a little time later the HP 82143A thermal printer and a barcode-reader called "HP 82153 Wand".

At those days I recognized that that something is missing to the very useful system: It was possible to read programs into the calculator from barcode on a sheet of paper, but not to print out a program. After opening the printer and looking at the mechanism I realized that there was no way doing it by software, because there is always a gap between the lines. At last I found a mechanical solution and published it together with a little program in the journal of the German HP41 user group CCD.

I offered to do the change for others and got in contact with people all around the world (even without internet).

Some time later HP produced the thermal IL printer HP 82162A which was able to print out barcode.

All the time I looked for a better way to run my barcode programs and finally decided to build a MLDL based on an article in the PPC Journal. I didn't like the size of the original board and soldered all the components on some hole raster plates fitting into a housing of the size of the HP41 but twice as high. My first MLDL had 4K words RAM and 4K words ROM. Unfortunately it doesn't exist any more and there are no pictures of it.

It was a useful device, but a little bit too big. My next Device was an EPROM-Box which was only 15mm high. It was the first prototype of the MBK-16 EPROM-Box and the start of some commercial success. I met a mathematician who sold HP41 programs to the German building society LBS and had a need of devices for storing a little more than the some bytes fitting on a magnetic card. From now on I was employed at the MBK and got paid for my work.

Getting commercial I: MBK EPROM-Boxes


Equipped board of a MBK-16 EPROM-Box Equipped board of a MBK-16 EPROM-Box

The first series of EPROM-Boxes was the MBK-16. It was produced about 250 times; all devices were soldered by hand, most of them by me. I've got only one equipped board left which will not work. It is labeled "MBK-BOX-16 (c) 1983 W.Maschke" on the top and "MBK-BOX-16" on the soldering side. It could be used with a set of 1 2716 and one 2764 EPROM for 8K words or with 1 2716 plus 2 2764 for 16K. It is possible to switch it to Port 1(+2) or 3(+4) on the PCB.


Equipped board of a MBK-32 EPROM-Box Equipped board of a MBK-32 EPROM-Box Setup of a MBK-32 EPROM-Box Setup of a MBK-32 EPROM-Box

The final series of EPROM-Boxes was the MBK-32. It was produced about 300 times; most devices were soldered by machine, some of them by hand. Also from this series I've got only one equipped board left which will not work. It is labeled "MBK-04 (c) 1984 W.Maschke" on the top and "MBK-04" on the soldering side. It could be used with many different combinations of EPROMs from 2716 up to 27256 and from 4K to 32K words size and could even be switched to the system area.

Getting commercial II: MBK ProfiSET

MBK-ProfiSET Prototype

MBK ProfiSET Prototype: Bad Board without holes MBK ProfiSET Prototype: Bad Board without holes MBK ProfiSET Prototype: Inside 1 MBK ProfiSET Prototype: Inside 2 MBK ProfiSET Prototype: Inside 3 MBK ProfiSET Prototype: Inside 4 MBK ProfiSET Prototype: Front MBK ProfiSET Prototype: Rear

From the start on there was also a need for a development device. My first MLDL had a lack of memory and I started to build the later called ProfiSET. There were 4(?) prototypes with a handmade PCB. One of them you can see on the picture. Another difference between the prototype and the series is the front without holes and no little red switch on the backside. I tried to run it and besides the batteries it is still working. The ProfiSET OS on EPROM is the latest one which was programmed. It is labeled "-ProfiSET 2" in CAT2 and has also the CAT2-label "MBKTOOLS-LBS" at the end. All ProfiSETs have different serial numbers (the number you have to type in with the function "INIT") besides my two devices (they both have got the number 002).

MBK-ProfiSET I and II

MBK ProfiSET: Inside the developers device MBK ProfiSET: Inside the developers device MBK ProfiSET: Developers device MBK ProfiSET: Developers device, front MBK ProfiSET: Developers device, rear MBK ProfiSET: Manual MBK ProfiSET: Empty PCB MBK ProfiSET: Empty PCB MBK ProfiSET: Equipped board MBK ProfiSET: Equipped board, soldering side MBK ProfiSET: 16K RAM Extension MBK ProfiSET: 16K RAM Extension

The difference between a ProfiSET I and II is only the name and some software. There is the same PCB inside. A ProfiSET with 32K RAM is a standard ProfiSET with additional 16K RAM soldered with wires on top. The pictures are taken from my "developers"-ProfiSET with 32K RAM and 16K ROM and some extra switches on top. The other pictures show the manual, an empty PCB, an equipped board (will not work) and a 16K RAM extension. The ProfiSET is still fully functional. When I tested the device 18 years after the last battery was changed I was very surprised. The battery is still working; the whole content of RAM was still there. The battery still has 3.08 V.

I don't remember how many ProfiSETs were built but it was about 150 devices. I've still got many empty PCBs left, but only one prototype, one "developer's device", one equipped board and one RAM-Extension (which is untested). The ProfiSET is one of the first build in series devices and was used to develop the W&W RAMBox.

Very small series or prototypes only.

The EPrommer - A EPROM-Programmer for the ProfiSET

MBK EPrommer MBK EPrommer: Connected to the ProfiSET MBK EPrommer: Connected to the ProfiSET MBK EPrommer: Empty board MBK EPrommer: Empty board

The EPROM-Programmer was designed for series, but was only built four times. At those times, you earned more money by doing the programming than by selling devices. That was the reason.

The device on the pictures is the only one I still own and there is only one empty board left. The device is still fully functional and is able to program sets of EPROMs from the content of the ProfiSET controlled by the ProfiSET OS and an HP41. Supported are 2716 to 27256 and 27C256. It has to be connected to a 220V 50Hz power supply.

A Centronics port for the HP41

PrInterFace PrInterFace

This device has not really got a name, I just call it "PrInterFace". It connects the HP41 port to a line printer. Inside is an EPROM-Box with additional I/O. It is powered by the HP41 and the Printer. I don't know, whether it is still functional, because it works only with the old EPSON-compatible line printers. I tried it with my Canon i550 and could see the CAT2 entries as well as the control light at the printer flashing when trying to print, but it doesn't really work with a modern Printer. Only this one prototype exists. The built-in functions are quite like the functions of the infrared portable printer. Switching between MAN/NORM/TRACE-Mode is done by software, some additional barcode software is inside, but I don't remember how it's handled.

The last try.

Small EPROM-Box: Inside Small EPROM-Box: Inside Small EPROM-Box

This device was only developed but never built in series. It is an EPROM-Box for one 27C256 (16K), but it never worked really. It showed me sometimes a CAT2, but not every time. At that stage of development the first EPROM inside a standard-size Module was available.

Contact (only in English or German): info@maschke.de.