Elektronika MK-61 - today I ordered one NIB

[Hlib]

Post: #25

(09-25-2014 07:59 PM)jebem Wrote:  ....And it is the only calculator that I know of showing the official price engraved in the back during the manufacturing process!
85 Rubles was the asking price in 1996, July. Calculators for the people!...

In 1996: $1 = 3600 Russian roubles. A price on the back cover of calculator did not reflect its cost after 1992. Also, look at the image of normal VFD in МК- 61 (after 5000 500 hrs at least). There were calculators for engineers, but also there were calculators with bad quality for ordinary people. Business decides instead of us.



http://s020.radikal.ru/i712/1512/d2/7160ec0d8d73.jpg

[HP67]

Thanks for this thread, Jebem. It is very interesting, I have been thinking about grabbing one of these. I'm sorry yours didn't arrive in perfect condition as advertised. That is very disappointing.

[John Smitherman]

(09-25-2014 07:59 PM)jebem Wrote:  Calculators for the people!

Volksrechner! ;-)


John

[walterhf]

Hi Jose,
Thank You very much for the manual translation.
Good Job!!!

I translated the MK52 manual, check Scribd.
It's kind of rough, but I know nothing about Russian,
May be useful for you.
I have several MKs on my collection, for some
Reason I like them, though they are a pain to work with,
Kind of magic device if you think on the circumstances that
The calculator was designed.
A tip: the older ones, from the '80s, are much better
crafted, also more reliable.

Regards

[Geoff Quickfall]

Does anyone have documentation on the brp3 and brp4 modules? I have both but no manuals and therefor no rom addresses to access.

Geoff

[walterhf]

Hi Geoff,
Check here:

http://www.hpmuseum.org/forum/thread-2345-page-2.html

you will find a .doc file, which is great because you can translate in Google,
if you don't speak Russian

[Geoff Quickfall]

Hello Walter,

Thanks for the pointer, started doing some translations at least for the titles and addresses. Looks like an interesting bunch of routines.

Geoff

[Hans-Peter]

Mine is just finished, with the TZ-tape. I only wait for the grey tape to make it perfect on the keys.
Between the keys is a printed self adhesive plasic paper.
The Manual is a little bit thin and I'm looking for some more hints.

The battery compartment had plenty of rust but after some cleaning, the calc works fine.

   
   

Hans-Peter

[walterhf]

Hi Hans-Peter,
Good Job!
Check here:

https://www.scribd.com/book/334050679

Mk52, Mk56 and Mk61 have similar manuals.
I found out that even the examples are the same.
The only difference is the explanation of the continuous
memory use (EEProm), on the Mk52 manual.
I'm still working on the translation, but at least
You can figure out some things.

Walter.

[HP67]

(12-26-2016 12:16 AM)walterhf Wrote:  Hi Hans-Peter,
Good Job!
Check here:

https://www.scribd.com/book/334050679

Mk52, Mk56 and Mk61 have similar manuals.
I found out that even the examples are the same.
The only difference is the explanation of the continuous
memory use (EEProm), on the Mk52 manual.
I'm still working on the translation, but at least
You can figure out some things.

Walter.

Hi, does anybody have a PDF copy of this? Apparently you have to pay to use scribd... not sure why anybody would post there.

[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.
  

[voltaage]

(09-19-2014 08:29 PM)Francois Lanciault Wrote:  I bought a MK-52 a few month ago. It works for about 2 days then died.

I am now a bit reluctant to order an other one...

François

Hello François.

Don't panic!. It is a common problem that these work for a bit, and then refuse to power on or to work properly. In my experience, when I ordered one NIB from e**y, it worked for a month before refusing to turn on; when it did, no matter what key you pressed but it returned to that transe. I started by replacing the only eletrolythic in the machine: a "K50" 20uF 25V capacitor. No change at all unfortunately. Then I took my soldering iron and reflowed all the solder joints in the board: all of them. I spotted some cold soldered points here and there, and corrosion of course (very little). Still no improvement. Lastly I took apart the keyboard assembly, removed all the left sponge debris, brushed the contact points on the motherboard (don't brush the ones on the plastic mat since they are VERY brittle and prone to falling apart) and replaced the keyboard sponge with a 0.5cm thick card size one found at a small portait. Oddly enough, I reassembled the moudule, placed the black protective case of the power supply board, and stored the calculator for 2 weeks (After doing the keyboard replacement, anything worked. I got so frustrated that I decieded to continue later and refresh my thoughts in the mean time). After that it worked perfectly. It has been working since (almost a year now) with the keypress feedback as it would originally have been; no repeated keypresses and no jingling candy inside the case (the keys, since the sponge wasn't printing the right force to keep them from playing in their spot, made a jingle noise when moved slightly because of the clearance. One of my friends made that joke when I presented the calculator to him before doing the repairs.)

In conclusion, consider these steps:

• Change capacitor in the power supply board
• Look for solder bad solder joints (corroded, cold, cracked).
• Remove debris between the contact layers of the keyboard assembly to ensure connectivity.
• Replace sponge of the keyboard assembly with original hole pattern to ensure keys aren't pressed twice (yes, the weight of a key can cause that).
  

In general terms, it is good to take a look at these too:

• Look for broken components.
• Look for smoke marks, water damage, battery acid corrosion, etc.
• Check for any weird objects inside the display (another MK61 I have has some of the epoxy used to glue down the control grid stuck underneath it, but that is a story for another post).
• Are your batteries ok? (1.5 volts each).
• Are the battery contacts ok? (Sometimes they have a thin layer of corrosion due to storage. Use the back eraser of a pencil to remove that).
• Is the back connector shorting correctly? (There is a lead touching the left pin of the connector at the back of the machine which supplies Vbatt to the machine; it is disengaged when the plug of the AC adapter is inserted, to avoid recharging non-rechargeable batteries).
• Is the power switch ok? (It should glide with ease, making a solid "clack" when toggled).
  

Finally, remember that this devices are 30y+ (yes, they might be NOS, but they haven't been used for a long time). Components get old, and sometimes need a time to "come back to life"; so give them that time as well.

PD: Sorry for replying after this long, but I just found this forum acquaintanced with it.

[HP67]

Thank you! I should find some sponge and fix a few of my Elektronikas.

[voltaage]

(12-09-2021 10:21 PM)HP67 Wrote:  Thank you! I should find some sponge and fix a few of my Elektronikas.

Wish you the most sucess! Plastic clips on these calculators are not to be trusted. When you think they'll flex out enough, they just snap off. I can anticipate that the search for that sponge will take long. After replacing the one on the keyboard... Why not having an extra bit around for the future? - I said to myself - I can only say that I'm still looking for that 0.5 cm sponge sheet. It sometimes too thick or not "spongy" enough. Good that I still have a bit left of the one in that frame.



Quick annotation regarding the keyboard assemby:

The plastic mat's traces on my MK61 are made out of some sort of carbon paste similar to the one often found in tv remote controls. This one I often see it fades out or tears apart with use/age. Mine's all right. I've seen some pictures of the MK52 having the traces made out of flat wire, like the IBM Model M. Seems that some of the MK61's were made like this, but very little is known from those variants. A very durable keyswitch option: metal vs metal instead of metal vs carbon paste. Not to be confused with the very early variants that have a tactile metal dome array, like in many of the HP's. Ultimate durability. But this is doomed if you want to change the sponge retaining the keys, since the black cover is plastic-riveted. Tic-Tac(TM) inside guaranteed.

[stanwax]

Greetings all
New here, and found this place through this and other threads popping up in google when searching for info on Russian RPN calculators.
I just got an MK61 last week to compliment my weird wonderful and frankly unique MS1103, which I bought about 5 weeks ago.
The MK61 was billed as NIB but as seems commonplace this is a stretch to say the least. However its in vgc with all the accessories (even if they have clearly come from other MK61s )
The mantissa '-' and the left most digit were barely glowing, indicating that classic contact problem, but I have managed to repair the display (despite me having one on the way as well - I thought I had nothing to loose.)
This thread in particular has been greatly helpful esp thanks to Jose for his superb translation. I am in the throws of translating the manual for the MS1103 so that will be avail if of interest soon - its 99% done. Also interesting to note the addressing issue pointed out by Danny, this helped me solve an issue I was having getting to grips with program branches that didnt work! I had worked out how to get round it but didnt understand why, until I read that info
I will perhaps make a post about the MC1103 and also one about the display repair, but for now hello to all and thanks for the super info in this thread
Rob

PS note to admins. I came here for the Russian stuff and know nothing of HP calcs, so the security questions were almost impenetrable for me. I had quite a few attempts before I managed to crack the HP mystery.

[Ajaja]

BTW, they are Soviet calculators, not "Russian". Most advanced models like MK-52 and MK-61 were developed and produced in Kyiv, Ukraine. MC1103 it's Kazan, Tatarstan.

[stanwax]

Yes of course you are right, but even Soviet isnt quite right as mine were both made after the fall of the USSR, despite clearly being deveolped during the Soviet era. I was aware the MK61 was made in Ukraine, and at first belived the MS1103 to be so too, but have since seen that it was made in what is now Russian republic....So im half right. But you knew what I meant
I work lots on Soviet Synths - which is where my fascination with Soviet electronics comes from, and many of these are similar in that they were developed during Soviet era but some remained in production into the early 90s. I love the electronics in them and im learing all the time

Rob

[toml_12953]

(11-12-2018 11:53 PM)HP67 Wrote:  Hi, does anybody have a PDF copy of this? Apparently you have to pay to use scribd... not sure why anybody would post there.

The poster gets a commission, maybe.

[EdS2]

(11-12-2018 11:53 PM)HP67 Wrote:  Hi, does anybody have a PDF copy of this?

There's a copy on the Internet Archive (as pdf, OCRed and also readable online)