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Tekmate 2402 rebuild and programming

A Rhodes
 

I recently got a Tekmate 2402 mainly because I thought it is cool and I like that it can piggyback to the 2440 scope I have. When I got it, it did not work. No hard disk, as expected. Both floppy drives non-functional. The battery in the NVRAM on the 286 MOBO was dead. I re-powered the NVRAM and replaced the FDDs. It worked well. It had no video, so I got a PC-104 VGA card.

The 286 mobo was designed as before there was a full standard for PC-104, nor for the mobo that also became a standard size.

I decided to replace the mother board with something faster. The Versalogic VSBC2 (using a "586" CPU) fits. It appears that it was designed to be a mostly drop-in replacement for the AMPRO LB/286 in the 2402. One issue is that it DOES have standard layout for the PC104 header which is a mirror image of the LB/286 connector.

Before I got the 2402, I was intrigued as to how the ISA bus header was connected. Was it a standard part, or was it a custom one for the 2402? Well, it is custom.... And it had a connector suitable for the mirror image PC-104 connector of the original LB/286 mobo. So, I had to make a PCB to convert the connector from standard to mirror image. Not a big problem. Also, the LB/286 is powered BY the ISA bus header through the PC-104 connector (not the other way around as would be expected). I maintained the power connections, and it CAN power the VSBC2 board. But I doubt the VSBC2 is designed to be powered properly this way. and I am sure the VSBC2 draws more power than the LB/286. So I modified the power cable to one of the floppies (also coming off the ISA header) to also power the mobo.

It works quite well.

Then I undertook the project for which I originally GOT the 2402 in the first place. I wanted to be able to store graphics images of the captures shown on the scope. I had hopes that the DSP-APP software for the 2402 would do that for me. But it does not. Also, I had hoped that the source code for the DSO-APP would be available. But I never found it. So I looked at some examples of C programming for the scope and wrote a very nicely functional program that interfaces to the scope in a similar manner to the DSO-APP software and will write SVG graphics files to the hard disk (yes, I added a flash-based hard disk), or to one of the floppies (selectable from the scope screen).

It writes SVG type files. This file type is rather generic, so lots of software can read and display/print it. For instance Internet Explorer can do so. I had hoped to write the program to save it in PDF format so it would be even easier to print using the easily available Acrobat Reader. But that has not been achieved yet.

It was quick for me to write the SVG part of the code because I had already written it for use on a microcontroller (e.g. arduino) for interfacting to the scope and saving to an SD card.

If anyone is interested in my project feel free to contact me here on this group.

-Tony

John Mullens
 

Tony,
Count me in as "very interested". I recently acquired a 2402A with FDD/HDD and it looks like I'm going to have to replace/reload the hard drive. Thoughts were to use this as a scope controller, general purpose GPIB master and as a driver for the two parallel-port-interfaced PROM programmers here in the lab...but I'm open to suggestions on additional functionality.
73 - Fred, N8YX

A Rhodes
 

What more would you like to know?

The limitation with the 2402 is simply its age. The hardware is well made so, that aspect of the age is not a big issue. But DOS is a problem. MANY modern interfaces assume that you have some version of Windows later than W98.

It was very difficult to find the national instruments GPIB driver and C programming library for DOS. Even national instruments itself doesn't know what drivers to use for the GPIB board that was distributed with the 2402. I eventually got it. Another difficulty then was a C compiler suitable for DOS. I ended up using Turbo-C 3.0. I had used that program (version 2) back in the day, but I forgot/didn't realize how much C (not even C++) has changed with the C99 and later standardizations. It was a little difficult to rearrange my brain to suit the early C language!

This entire project was very interesting BECAUSE this hardware was used as the foundation for several different standards (PC-104 for the video and EBX for the mobo). But they do not follow the exact standard that was devised subsequently!

I think that it is very worthwhile to upgrade the motherboard to the Versalogic VSBC2. It is a drop-in replacement physically. and I only needed to modify the connectors on the serial ports (two 2x10, to one 2x20), and the PCB to mirror the PC-104 connections for the ISA bus header, and a power supply for the mobo.

But after that inconvenience you get a lot more RAM, and more speed, and 486 instruction set with math coprocessor. This HW is completely capable of running windows 98, which will still allow 16-bit DOS programs to run fine (usually). I am using DOS 6.33 and not windows.

If you wanted to keep the 286 motherboard, then you pretty much need to stay with DOS, which is not a big problem at all. 1M of total memory is quite sufficient for most purposes in the usage of the 2402A. I simply liked the challenge of making what I call a 2402 "B". Or maybe it should be called the "C" version. The "B" version could have been a 386 CPU. and a 486/586 might have been the "C" version!

Let me know what more info you would like and I will help out any way I can

-Tony

A Rhodes
 

I have uploaded to Github a few different repositories under the user name "Tek-User".

You can use google for "github two-user".

There are 4 project repositories. One on writing new software for the 2402.

Another on repairing an old 2402 and getting it working. And then upgrading the 2402 to a 133MHz 586 EBX motherboard and the complexities that are encountered.

Another project ports the new programming from the first project listed here and placing it on an arduino. A tiny arduino can largely replace the entire 2402 as an embedded system with the user interface through the scope.

I have found and placed in these repositories various software packages relating to the 2402.

One software package I have NOT found is the Tektronix "Program Development Software". This apparently has the source code used for the "dso-sh" and "dos-app" software packages provided by Tektronix. I have searched for the development software by thoroughly googling all variations and themes of this topic and found nothing.

Does anyone here have any leads for the Program Development Software?

-Tony

A Rhodes
 

Oops. The search term I mention should be:
"Github Tek-user"

Sorry!

Tony Fleming
 

On Tue, Aug 6, 2019 at 11:22 AM A Rhodes <@ARHODES> wrote:

I have uploaded to Github a few different repositories under the user name
"Tek-User".

You can use google for "github two-user".

There are 4 project repositories. One on writing new software for the
2402.

Another on repairing an old 2402 and getting it working. And then
upgrading the 2402 to a 133MHz 586 EBX motherboard and the complexities
that are encountered.

Another project ports the new programming from the first project listed
here and placing it on an arduino. A tiny arduino can largely replace the
entire 2402 as an embedded system with the user interface through the
scope.

I have found and placed in these repositories various software packages
relating to the 2402.

One software package I have NOT found is the Tektronix "Program
Development Software". This apparently has the source code used for the
"dso-sh" and "dos-app" software packages provided by Tektronix. I have
searched for the development software by thoroughly googling all variations
and themes of this topic and found nothing.

Does anyone here have any leads for the Program Development Software?

-Tony