Hmmm, that looks familiar :)

Congratulations, I'm glad you got it running. What are we up to now, three running Kenbak-1 Series-2 machines? Four, including Grant. That makes us a more exclusive group than owners of original Kenbak's :D

I bet you felt like yelling, laughing, and crying all at the same time when you found that. :) Were you studying the trace layout of the board to debug the circuit and see the lack of a solder joint by accident?

So, have you run any of the examples from the manual yet?

Grant

Finding the error
 

I suspected the IC52 and I replaced it with the one in IC77. Then the problem of all the LEDs being lit constantly was gone, and I wrongly concluded I found the answer. But it just accidentally worked because I took out IC77. When I put in a new 7420 at IC77 it was back.

Since I swapped IC25 and IC41 before (with the 7400 from IC99 remember), the only thing I could think of is that IC25 was upside down which can easily be detected by checking the voltage at 7 and 14. Only then I saw 1.5 V at pin 14 of IC25 and started disassembling the machine.

Warned by Geoff, I carefully checked the board after soldering and back then I found two similar incidents. But apparently overlooking a third.

Finding the error
 

I suspected the IC52 and I replaced it with the one in IC77. Then the problem of all the LEDs being lit constantly was gone, and I wrongly concluded I found the answer. But it just accidentally worked because I took out IC77. When I put in a new 7420 at IC77 it was back.

Since I swapped IC25 and IC41 before (with the 7400 from IC99 remember), the only thing I could think of is that IC25 was upside down which can easily be detected by checking the voltage at 7 and 14. Only then I saw 1.5 V at pin 14 of IC25 and started disassembling the machine.

Warned by Geoff, I carefully checked the board after soldering and back then I found two similar incidents. But apparently overlooking a third.

Assembler
 

So exactly how do I go about using AS? I want to write a program to calculate E (Euler's constant). The series converges rapidly and you only need to maintain the sum and the term.

I'm a little confused, is it working yet or are you still having problems? :confused:

What operating system are you using? Linux/Windows/OSX?

The version of AS on the internet does not support the Kenbak. I downloaded his source and added the Kenbak myself. If you want to compile the C source code yourself I can e-mail you that. Otherwise I can compile a binary for you.

Everything is OK
 

Everything works properly and I tested some loops to initialize the term and the series. Tonight I wrote the part that will do divisions on arbitrary numbers, but I didn't put it in yet. It is 62 bytes. I need to do the one that does the adding, but that is pretty trivial I guess. So I must be able to calculate E with a precision of 64 bytes which is 154 digits.

And I prefer Linux since I know that best. So if you can send me the sources, I would appreciate it.

I e-mailed you the source code and a fixed include file. Please let me know if you didn't get it. Its a tar.gz file so I doubt a virus scanner would reject it. ;)

Also, let me know how it compiles for you. Its going to be exciting to create a library of KENBAK-1 programs!

A project on the back burner is a RS-232 device which could automate button pushing. For example, it could load an intel hex file into the kenbak, or read the kenbak memory image out.

Since the "PC" and registers are regular RAM locations the state of the KENBAK could be preserved without power to the KENBAK.

The project I'm planning on would use a single ATMEGA8-16PC, the RS-232 level converter, and a few capacitors. It will be open source. All of those parts should be easy to get where you live.

Unless you want the pretty PCB then you could just build it yourself. :)