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Thomas Radtke · 11-30-2017, 01:28 PM

FWIW: Lately, some of those amazing Elektronika MK-52 appeared on TAS at really good prices. I had one several years ago but its EPROM was already dead. No longer a collector, I'm not interested anymore but thought some of you are.

Michael de Estrada · 11-30-2017, 06:38 PM

(11-30-2017 01:28 PM)Thomas Radtke Wrote: FWIW: Lately, some of those amazing Elektronika MK-52 appeared on TAS at really good prices. I had one several years ago but its EPROM was already dead. No longer a collector, I'm not interested anymore but thought some of you are.

I have an MK-52, but it is totally kaput. Finding them is not difficult, but finding one in good working condition is the problem. Do you have any of the accessory modules ?

jebem · 12-01-2017, 03:47 PM

I see these Soviet era machines as valuable items from the point of a collector's view.
I don't see them as a choice for regular utilization, though. The keyboard is terrible as the keys have almost no travel when pressed and can fail to register too.

One common reason to see these machines failing (not only this model) are the electrolytic capacitors. On every single specimen that i checked, at least one capacitor was defective. They either lose the capacitance or/and act as resistors to DC.

This issue is not exclusive of Ukrainian made calculators. I see this on every sort of equipment, no matter its origins. Electrolytic caps are like rechargeable batteries in the way they fade away with the passing time, even when not used.

The VFD is prone to fail as well, but the good news is that we can still buy new VFD spare parts on Ukrainian and Russian eBay sellers.

Thomas Radtke · 12-02-2017, 06:33 AM

(11-30-2017 06:38 PM)Michael de Estrada Wrote: Do you have any of the accessory modules ?

No, and never had one of them.

@jebem, I don't know if those VFDs tend to fail; Mine (other calculators) all still work after decades. One of those sellers displays the VFDs of the respective calculators and they appear of equal brighness. Feedback is ok. And yes, the keys have a terrible feel, but at least mine surprisingly never had a problem concerning registering entries. But my only true complaint about the MK-52 is speed. It was the slowest calculator I ever had.

jebem · 12-08-2017, 08:53 AM

Halo, Thomas,

The keyboard can fail depending on how the calculator was stored or perhaps badly used.
I usually fix it by dismantling and cleaning the membranes and replacing the foam.

The VFD can present some defects, like not illuminating properly or just go dead.
I had to replace one that had the filaments broken inside.
Other members have posted here for defective VFD's and some took the time to reapir them! I just don't care about ir, as I prefer to replace it with a new unit, as least while I can find them in eBay:
http://www.hpmuseum.org/forum/thread-200...l#pid52833
http://www.hpmuseum.org/forum/thread-234...l#pid27923
http://www.hpmuseum.org/forum/thread-234...l#pid48405

These machines can be found on eBay "as new", despite the more or less damaged boxes they come in.
In fact some of them were never used, they just didn't sell them and they were stored for some years until Ukraine and Russia people discovered eBay...

Despite the looks and used technology, these MK 52 and 61 are not that vintage, despite they are a MUST in any calculator collector IMHO.
I enjoy that vintage looks of the VFD displays, but it is me, I'm a tube/valve/Elektronenröhren pearson.

Thomas Radtke · (This post was last modified: 06-05-2021 08:28 AM by Thomas Radtke.)

So, I got a new one.

TAS seller got excellent comments, so I guess he's a good one. The calculator looks as described (NIB, VFD bright and equal over all digits). He wrote he replaced capacitors and ensured the EEPROM being ok. Thus far, so good.

My first attempt after many, many years of having one (with defect EEPROM) are not successfull. I doubt the chip is ok but I may have done something wrong.

So, is my approach correct:

Second switch set to с to clear EEPROM, з to write to EEPROM, сч (считать?) to read from EEPROM.

Fourth switch set to д for data memory, п for program memory.

Is there anything unusal that I can do wrong?

Even better if you have a small safe step-by-step procedure to check if the EEPROM is ok.

Thanks,

Thomas

Edit: I have a minimum of russian language knowledge. Better than nothing but really not much. So a pointer to a russian source would be ok, too (so I can clip what I don't understand in the Google translator).

apoluekt · 06-05-2021, 11:29 AM

Nostalgy, nostalgy... I've used MK-52 quite a lot like 25 years ago.

(06-05-2021 08:25 AM)Thomas Radtke Wrote: So, is my approach correct:

Second switch set to с to clear EEPROM, з to write to EEPROM, сч (считать?) to read from EEPROM.

Fourth switch set to д for data memory, п for program memory.

Is there anything unusal that I can do wrong?

Even better if you have a small safe step-by-step procedure to check if the EEPROM is ok.

Thanks,

Thomas

Edit: I have a minimum of russian language knowledge. Better than nothing but really not much. So a pointer to a russian source would be ok, too (so I can clip what I don't understand in the Google translator).

Your understanding of the switches is I believe correct. I recall that using EEPROM is rather convoluted. You should type in a correctly formatted address and then press "A-up", "down-up". Here are a few details in English: http://www.rskey.org/mk52, and of you want an official manual in Russian is here (which is pretty much unreadable even if you understand Russian well).

Thomas Radtke · 06-05-2021, 04:15 PM

(06-05-2021 11:29 AM)apoluekt Wrote: [...] an official manual in Russian is here (which is pretty much unreadable even if you understand Russian well).

Great! Thank you very much, that is very helpful.

Stevetuc · 06-06-2021, 05:37 AM

(06-05-2021 04:15 PM)Thomas Radtke Wrote:
(06-05-2021 11:29 AM)apoluekt Wrote: [...] an official manual in Russian is here (which is pretty much unreadable even if you understand Russian well).
Great! Thank you very much, that is very helpful.

You might find this emulator useful in checking usage of the MK-52
http://www.emulator3000.org/c3.htm
Disclaimer: I haven't checked it out myself, just was interested if such was available..

Thomas Radtke · 06-06-2021, 09:00 AM

(06-06-2021 05:37 AM)Stevetuc Wrote: You might find this emulator useful in checking usage of the MK-52
http://www.emulator3000.org/c3.htm
Disclaimer: I haven't checked it out myself, just was interested if such was available..

Nice emulator, thank you!

So, it seems I'm doing something wrong as I cannot store anything on the emulated eeprom, too. I start feeling stupid. Embarrassing.

Thomas Radtke · 06-08-2021, 12:33 PM

Thanks to jebem ...

https://www.hpmuseum.org/forum/thread-23...nika+mk-52

... I was able to readjust the -15V line and now enjoy a fully working MK-52.

I guess the seller, who went through this with me, used a power adaptor that brought that voltage line over die edge, but my Eneloops failed.

When open, I noticed he actually replaced some capacitors. Quite cool.

Hlib · 06-11-2021, 03:21 PM

I use an emulator (not a simulator) for the MK-61, which allows you to store 99 programs. In the android smartphone, it runs on a single battery charge three times longer than the physical calculator MK-61/52. If you insert a single Schottky diode into the power supply circuit in a real calculator, you will have an analog of an uninterruptible power supply when the calculator operates from a 110/220 V, if the main batteries are inserted into the power compartment. Here is a free emulator for android (this is the development of a fan of MK-61 from Russia):
https://drive.google.com/uc?id=1eDLoxugL...=downloadl

Thomas Radtke · 06-11-2021, 08:07 PM

Thanks Hlib!

I'm running the calc from Eneloops (actually IKEA LADDA, nothing else than Eneloop Pro/Japan for the time being). Perfect solution for me.

@apoluekt, thought about the nostalgia thing. It's rather curiousity as I have no emotional connection to soviet calcs. This, and the fact that it's a full blown budget RPN calculator. Used to use a 35s at work since it would break my heart if my older HPs would be stolen. But actually the MK-52 is better suited. Programs survive a battery change no matter what.

Amazing I found some real good reasons to justify my purchase ;-).

Hlib · 06-12-2021, 12:04 PM

Quote:Amazing I found some real good reasons to justify my purchase

Although these were my first calculators (MK-61/52 from1985. 12), now I have more love for the hp-50g, which made a real revolution in RPN➜RPL. For the sake of hp-50g, I bought a separate smartphone for the go49gp. Unfortunately (or fortunately), my mental abilities do not allow me to master the HP-Prime calculator perfectly, so I remain a fan of the hp-50g and Droid48.

Thomas Radtke · 06-12-2021, 01:02 PM

Yeah, but the MK-52 is $20, the 50g like $200? I got mine in a lucky moment for about $80 IIRC. But I consider it non-replaceable.

Hlib · 06-12-2021, 04:00 PM

Quote:Yeah, but the MK-52 is $20, the 50g like $200? I got mine in a lucky moment for about $80 IIRC. But I consider it non-replaceable.

Yes, the hp-50g has no alternative replacement. But: the keys in the hp-50g very degrade already after 10,000 clicks on each. The hardwarе does not stand up to any criticism. These are very bad characteristics. The quality of some TI/CASIO is a recognized fact in the world of calculators. Nevertheless, the very concept of the hp-41/48gx/50g will be in demand among some fans for a very long time. I still can`t get cured of RPN/RPL :-)