Elektronika MK-61 - today I ordered one NIB

[Danny]

Hi,

I recently added a nice MK-61 to my collection, and was really glad to find Jose's translated manual : thanks a lot for the great work !

However, I found what seems to be a misinterpretation of the original manual, concerning steps numbers. Let me explain :

• A footnote on page 21 says "step 00 is not available to store any instructions. The first memory address available to store a command is 01".
• In pages 40-41, there's an example of looping calculations using DSNZ0, with a footnote saying "The original Russian manual lists the addresses starting from 00, which is not correct, because the first usable address to store instruction codes is 01".
  And indeed, after the DSNZ0 there's a GOTO to the 2nd step of the program (step 02 : RCL 0), which seems logical and consistent with the rules stated above.
• Seeing how the instructions are displayed on the MK-61, it's easy to believe that the number on the right is the current step, with step 00 containing no instruction, and consequently that the 3 numbers on the left are the current and 2 previous instructions :
  
  

But when I tested this looping program on my MK-61, the loop went back to the 1st step, not the 2nd ! :o

Since I didn't find anyone talking about this offset of the steps anywhere on the web, I digged more and found this web page explaining the MK-61's keys, with some interesting info at the bottom. It says that :

• Steps begin at zero.
• The rightmost two digits in the display indicate the current program step (this I knew already, ok).
• But more importantly, the 3 keycodes displayed on the left are the codes of the previous program steps !
  

Then I also tried to translate page 98 of the original manual, that explains how the program steps are displayed, and here's what it says :

• The number on the right is the index of the current step (06 in the original manual's example).
• The 3 codes on the left are those of instructions 03, 04 and 05 (so the previous steps indeed).
  

This explains why all program listings begin with step 00 in the original manual !
Because programs actually start with step 00, not step 01.

So with the same picture from Jose's manual :



On the 3nd line here, for example :

• 22 is the instruction in step 01.
• 20 is the instruction in step 00.
• the current step is 02 : we can't see it, but we'll overwrite it if we enter a new instruction now.