Poll: Is the MK-61 worth trying to use?
Yes! After a few drinks it starts to look ok after all
No! After one drink you will head for the nearest recycle bin
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MK-61... bad as it seems?
11-12-2018, 05:16 PM (This post was last modified: 11-13-2018 12:09 AM by HP67.)
Post: #1
MK-61... bad as it seems?
I just got one of these today and I am a little shocked at how bad the mechanicals are on these. I know Jebem has done a lot of work and maybe other guys on here also have experience.

1st thing is the on/off switch seems seriously out of whack. The calculator doesn't seem to want to turn on most of the time. Is this normal and is there an easy fix for this?

I'll go over the English manual somebody (Jebem?) came up with. Thank you! This will allow me to bug my Russian friends with more important/dumber questions when the time comes.

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11-12-2018, 05:45 PM
Post: #2
RE: MK-61... bad as it seems?
I bought one two years ago. Supposedly NOS. In fact it’s at best OOS (old old stock).
So. Never used but like used for a long long time by many people. A real tour de force ! Weak display, bad plastic, weak keyboard, unabled to work with fresh batteries (works with charger). But very cheap.

In contrast there’s the Elektronika MK 85, a Casio like Basic pocket computer, which is very well done. Better than japanese models.

Look at the last images.

http://www.emmella.fr/page5163-5970-1112...-3817.html

My site http://www.emmella.fr
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11-12-2018, 06:21 PM
Post: #3
RE: MK-61... bad as it seems?
Thanks Sad

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11-12-2018, 07:27 PM
Post: #4
RE: MK-61... bad as it seems?
A little bit awful but a RPN

   

Latin letters are helpful for everyday use.
The mechanism is agrrrrrrr. The display filter glass has some fog areas.....
But a beautiful, toy.
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11-12-2018, 07:35 PM
Post: #5
RE: MK-61... bad as it seems?
here is the mask for Latin.


Attached File(s) Thumbnail(s)
   

.zip  MK61 Layout 2.zip (Size: 22.69 KB / Downloads: 18)
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11-12-2018, 07:42 PM
Post: #6
RE: MK-61... bad as it seems?
(11-12-2018 07:35 PM)Hans-Peter Wrote:  here is the mask for Latin.

Great work! How are you printing it?

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11-12-2018, 10:16 PM
Post: #7
RE: MK-61... bad as it seems?
I printed on a self adhessive paper of water resistant quality (somme sort of plasitc).
Then I cuted stripes with the blue and yellow keys.
The labels on the keys are made with a p-touch writer (black on white and white on black tape).

   
   
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11-12-2018, 10:17 PM
Post: #8
RE: MK-61... bad as it seems?
(11-12-2018 05:16 PM)HP67 Wrote:  I just got one of these today and I am a little shocked at how badly the mechanicals are on these. I know Jebem has done a lot of work and maybe other guys on here also have experience.

1st thing is the on/off switch seems seriously out of whack. The calculator doesn't seem to want to turn on most of the time. Is this normal and is there an easy fix for this?

I'll go over the English manual somebody (Jebem?) came up with. Thank you! This will allow me to bug my Russian friends with more important/dumber questions when the time comes.

The keyboards on all of these are quite bad, as the foam that keeps the keys up has disintegrated. The keyboard feel can be very much improved by replacing the foam. It will still be really bad, but much improved Smile
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11-12-2018, 11:03 PM
Post: #9
RE: MK-61... bad as it seems?
(11-12-2018 10:16 PM)Hans-Peter Wrote:  I printed on a self adhessive paper of water resistant quality (somme sort of plasitc).
Then I cuted stripes with the blue and yellow keys.
The labels on the keys are made with a p-touch writer (black on white and white on black tape).

This is really great! Any chance you could produce sets and sell them to your fellow HP Museum members?

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11-12-2018, 11:06 PM
Post: #10
RE: MK-61... bad as it seems?
(11-12-2018 10:17 PM)Harald Wrote:  
(11-12-2018 05:16 PM)HP67 Wrote:  I just got one of these today and I am a little shocked at how badly the mechanicals are on these. I know Jebem has done a lot of work and maybe other guys on here also have experience.

1st thing is the on/off switch seems seriously out of whack. The calculator doesn't seem to want to turn on most of the time. Is this normal and is there an easy fix for this?

I'll go over the English manual somebody (Jebem?) came up with. Thank you! This will allow me to bug my Russian friends with more important/dumber questions when the time comes.

The keyboards on all of these are quite bad, as the foam that keeps the keys up has disintegrated. The keyboard feel can be very much improved by replacing the foam. It will still be really bad, but much improved Smile

Yeah, the keys are hanging loose on mine at all angles. It's certainly NOS, although the display is scratched and looks like it fell off a truck on the highway, the markings on the keypad and keys are all clean and clearly it was not used.

Thanks for the idea about the foam. I'm reading through Jebem's thread about this model. I'll see if it's easy to disassemble.

I tried mine with new Eneloops and it did not want to turn on most of the time. I thought it was a bad switch. But it also ran for 30 seconds and then shut off. So I put the new Eneloops in a charger and after a few hours the green lights are still on. So maybe the batteries were dead in the package. I'll try again tomorrow.

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11-12-2018, 11:59 PM
Post: #11
RE: MK-61... bad as it seems?
I've found that carbon AA batteries are a better fit for these.
The modern high capacity batteries tend to push the size limit for AA cells and on my MK-52, four in a row don't fit the battery compartment. It isn't so bad with the MK-61. Carbon batteries are also slight higher voltage.

The mechanical construction of these calculators are dreadful.


Pauli
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11-13-2018, 12:07 AM (This post was last modified: 11-13-2018 12:08 AM by HP67.)
Post: #12
RE: MK-61... bad as it seems?
(11-12-2018 11:59 PM)Paul Dale Wrote:  I've found that carbon AA batteries are a better fit for these.
The modern high capacity batteries tend to push the size limit for AA cells and on my MK-52, four in a row don't fit the battery compartment. It isn't so bad with the MK-61. Carbon batteries are also slight higher voltage.

I've got a couple MK-52s waiting for me at the post office so I'll find out soon enough. They seem to fit fine in the MK-61 but it doesn't seem to make any difference. I just could not see taking a chance with batteries leaking and killing a perfectly deserving calculator that made it this long without falling apart or rusting.

I hope Jebem or one of the guys who wrenches on these is willing to start a business doing cheap Elektronika repairs.

(11-12-2018 11:59 PM)Paul Dale Wrote:  The mechanical construction of these calculators are dreadful.

Understatement!

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11-13-2018, 01:55 AM
Post: #13
RE: MK-61... bad as it seems?
(11-12-2018 11:59 PM)Paul Dale Wrote:  I've found that carbon AA batteries are a better fit for these.
The modern high capacity batteries tend to push the size limit for AA cells and on my MK-52, four in a row don't fit the battery compartment. It isn't so bad with the MK-61. Carbon batteries are also slight higher voltage.

The mechanical construction of these calculators are dreadful.


Pauli

I tried some flat-top AA (which I had bought for Woodstock HPs) in my MK-52. The fit is a good bit better as they are shorter.

Ditto on the mechanical construction critique. Capitalism 1, Marxism 0.
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11-13-2018, 03:16 AM
Post: #14
RE: MK-61... bad as it seems?
The standard for AA batteries allows a 1.3mm variation in length (49.2 to 50.5 mm) and a 1.0mm variation in diameter (13.5 to 14.5 mm). Older lower capacity batteries tended towards the smaller end of these ranges, modern ones tend towards the higher end.

I was surprised that the variation was permitted to be so much but it does explain the poor fitting that is sometimes seen. Perhaps even the Spice series's broken battery terminals?


Pauli
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11-13-2018, 06:31 PM
Post: #15
RE: MK-61... bad as it seems?
(11-12-2018 11:03 PM)HP67 Wrote:  
(11-12-2018 10:16 PM)Hans-Peter Wrote:  I printed on a self adhessive paper of water resistant quality (somme sort of plasitc).
Then I cuted stripes with the blue and yellow keys.
The labels on the keys are made with a p-touch writer (black on white and white on black tape).

This is really great! Any chance you could produce sets and sell them to your fellow HP Museum members?

The idea is not bad but my day has not egnough hours to do that for the comunity. Perhaps some one in retirement?
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11-13-2018, 07:10 PM
Post: #16
RE: MK-61... bad as it seems?
(11-13-2018 06:31 PM)Hans-Peter Wrote:  
(11-12-2018 11:03 PM)HP67 Wrote:  This is really great! Any chance you could produce sets and sell them to your fellow HP Museum members?

The idea is not bad but my day has not egnough hours to do that for the comunity. Perhaps some one in retirement?

We could ask Eric if he could do an overlay, but I suspect the wp34 overlays were quite a challenge already and he won't be too keen on this.
I could ask a friend who has a cutting plotter, but he is probably starting a new job soon, so he might not have spare time for this...
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11-14-2018, 06:27 PM
Post: #17
RE: MK-61... bad as it seems?
(11-13-2018 01:55 AM)burkhard Wrote:  
(11-12-2018 11:59 PM)Paul Dale Wrote:  I've found that carbon AA batteries are a better fit for these.
The modern high capacity batteries tend to push the size limit for AA cells and on my MK-52, four in a row don't fit the battery compartment. It isn't so bad with the MK-61. Carbon batteries are also slight higher voltage.

The mechanical construction of these calculators are dreadful.


Pauli

I tried some flat-top AA (which I had bought for Woodstock HPs) in my MK-52. The fit is a good bit better as they are shorter.

Ditto on the mechanical construction critique. Capitalism 1, Marxism 0.

I saw some zinc carbon today but my experience with them 40 years ago insures I'll never buy them again. I bought some alkalines and the MK-61 is still not happy about turning on, but at least with these batteries it stays on. With the Eneloops it either died or started producing weird results on the display. I guess it cannot tolerate voltage that low.

Got my MK-52 today and it is much better in all regards, as you guys noted.

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11-14-2018, 07:33 PM
Post: #18
RE: MK-61... bad as it seems?
(11-14-2018 06:27 PM)HP67 Wrote:  Got my MK-52 today and it is much better in all regards, as you guys noted.

Hold on...You found that the MK-52 is better than the MK-61?
I have only experience with the MK-52 and didn't think its construction / build was all that great.
I guess I should really avoid the MK-61!

I will say, I think part of the appeal of these is the Cyrillic letters. A picture of a translated keyboard to reference (for a while until I get fluent) would be great, but I don't think I want to cover up one of its few charms. :-)
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11-14-2018, 07:48 PM (This post was last modified: 11-14-2018 07:51 PM by HP67.)
Post: #19
RE: MK-61... bad as it seems?
(11-14-2018 07:33 PM)burkhard Wrote:  
(11-14-2018 06:27 PM)HP67 Wrote:  Got my MK-52 today and it is much better in all regards, as you guys noted.

Hold on...You found that the MK-52 is better than the MK-61?
I have only experience with the MK-52 and didn't think its construction / build was all that great.
I guess I should really avoid the MK-61!

I will say, I think part of the appeal of these is the Cyrillic letters. A picture of a translated keyboard to reference (for a while until I get fluent) would be great, but I don't think I want to cover up one of its few charms. :-)

Yes in my case. I am sure it depends a lot on the manufacturing date, what the guys on the assembly line were drinking that day etc. In my case my MK-61 does not want to turn on, the keys are like the teeth of a 150 year old pipesmoker, etc.

The MK-52s I got (two, one I gave as a gift) were in much better shape, the keys are all standing tall and the sponge seems to give them relatively even pressure, and they turn on and function without begging and pleading. Many people here read Russian so I'll have help from friends and coworkers. The main thing for me was to know where the Enter key was. Thank you, Jebem!

For me the appeal was finding something made somewhat close by (many people still remember Czechoslovakia under the communists) and that uses RPN. And the MK-52 is supposed to be unusual because of the PROM memory, modules, etc. Too bad the construction is so shoddy. Anyway they come with schematics unlike most other calculators. So they should be repairable Wink

I have an MK-54 coming soon. I'll report on that when I get it and post a few pics of the trio.

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