DIY calculator repair the screen does not work

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Some of the calculator buttons stopped working.

Let's open the calculator and see what's inside. This will help us figure out why the buttons are not working.

Due to unknown circumstances, the internal board cracked (apparently brute force was used for incorrect calculations), but the copper tracks are intact. Let's remove the fee.

It is held in place by plastic rivets. They will have to be carefully cut off, after which the board can be removed.

Obviously, the graphite tracks are damaged. Let's check them with a tester to make sure they are open.

We were convinced that you can start repairing.

Their big drawback is that nothing can be soldered to them. Or are there ways?

In any case, you first need to clean up the places near the damaged areas.

Conductive glue, which is, but it is not known where, will help here. Therefore, you need to build a replacement from scrap materials.

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11/21/2015 at 20:00 lvl expressed:

It is also possible to precipitate copper by electrodes from copper sulfate.

11/22/2015 at 16:21 George expressed:

Yes, in theory, a good idea.

I'm not sure if the process will go fast enough due to the relatively high resistance of these tracks.

05/21/2016 at 18:08 abreu expressed:

How to cut rivets neatly?

05/21/2016 at 19:58 George expressed:

With a paper knife, it's sharp enough to cut them neatly.

05.01.2018 at 12:08 George expressed:

When I did this I did not know about the silver conductive glue. You can buy it in China and probably not only there. It could help to fix this calculator much easier and faster. I am attaching a photo.

and does not interfere with life, but I do not like it.

Questions:
- what is the reason for the violation? no contact?
- is it possible to repair without replacing the display?

opened it! not a single latch was damaged, although there are 6 of them in total 😀
there are no plumes, as well as conductive rubber.
everything is just like a cyst there: it is soldered, like a microcircuit

in general, the display is from the drgb-01 dosimeter, which, in particular, was used in the last bombard
there in the pictures everything is OK with the segment, because I restored it with Photoshop
in fact, at home, everything looks like this (click on the image to enlarge):

(the photo was taken so that the tracks are visible; the flare from the lamp)

from the back it looks like this:

So what do we see?
Iridescent over the output of a non-working segment - can it be air that got there during the manufacture / installation of the display, the cause of non-contact? Manufacturing defects?
Behind everything is ok.

There is an assumption that the problem may be in the K176ID2
But in general, all this is not so important, since the segment is unnecessary (its constant presence / absence does not affect the similarity of the numbers, does not entail an error in the readings).

a little pun: removing the case cover, I saw a red LED on the diagram, which lights up when the device is turned on. There is no hole on the lid to see it. So that's it. The diode is there and shines, but no one will see it until the cover is removed.

Ta-a-a-a-k. Found a way out of the situation

what have I done?
I slobber the tip of a manicure knife (which I used instead of a screwdriver) and poked it at the place indicated by the circle
before that I poked there with a slobber, - it did not help
she (saliva) seeped into this "iridescence" and everything lit up as expected

the last two questions:
- will it dry up and fail again? (here they told me that they could refuse forever 🙁 because the contacts are made of tin oxide and dissolve in water, - but I hope that the entire contact will not dissolve)
- what to poke there, so as not to refuse?

Has dried up. )
A second attempt led to the same result. It shone, and shone until it dried out, gradually dimming.
I will no longer experiment with saliva))

The question remains:
- what to poke there, so that it does not refuse and does not dry out?

Has dried up. )
A second attempt led to the same result. It shone, and shone until it dried out, gradually dimming.
I will no longer experiment with saliva))

The question remains:
- what to poke there, so that it does not refuse and does not dry out?

Conductive varnish is sold on the radio market, you can try to drip a ma-a-a-scarlet drop on (in) contact.

P.S. Not 100% sure what will help. The varnish also dries and shrinks and decreases in volume. In theory, if it gains a foothold on the contacts, it will simply stretch. It is still unclear how the deposition on glass will behave (in terms of dissolution).

You can try by taking apart some unnecessary clock or calculator (the principle of spraying on glass is the same everywhere)

I restored the indicators a couple of times, albeit without the use of varnish. In my experience, the spraying holds well, unless of course it is scratched. I repeatedly wiped (very intensively) such spraying with alcohol, everything was superb and did not wash off.

Use the same tip of the knife to drive the graphite powder into it.

PS If the LED is not parallel to the power supply, then it could serve to catch bugs.

There the hole into which you propose to “hammer in” something has a width of a fraction of a millimeter. Those. you cannot "hammer" there without destroying the display.
And the non-contact is precisely between the layers of glass, or rather, between the contact and the track to the segment.

Conductive varnish is sold on the radio market, you can try to drip a ma-a-a-scarlet drop on (in) contact.

P.S. Not 100% sure what will help. The varnish also dries and shrinks and decreases in volume. In theory, if it gains a foothold on the contacts, it will simply stretch. It is still unclear how the deposition on glass will behave (in terms of dissolution).

You can try by taking apart some unnecessary clock or calculator (the principle of spraying on glass is the same everywhere)

I restored the indicators a couple of times, albeit without the use of varnish. In my experience, the spraying holds well, unless of course it is scratched. I repeatedly wiped (very intensively) such spraying with alcohol, everything was superb and did not wash off.

Soldering is not easier =)
I was so soldered out of me that ay-ay-ay)))

My brother advised me to use some kind of marker with which they draw diagrams. What kind of if earlier the boards were varnished and etched, then there are some markers / markers with which you can draw tracks. Now this is closer to the truth - because this marker draws with a liquid, which then dries up.
Is the same conductive varnish applied there?

But my brother doesn’t have this marker, so either I’ll wait until he buys it, or I’ll have to bother myself with a visit to the radio market.

Or I take some more advice =) What is needed is a liquid, non-viscous, which can be put there on the tip of the needle, and which either does not dry out, or dries up, without ceasing to be conductive. ))

• 

Is your TV, radio, mobile phone or kettle broken? And you want to create a new topic about this in this forum?

First of all, think about this: imagine that your father / son / brother has an appendicitis pain and you know from the symptoms that it is just appendicitis, but there is no experience of cutting it out, as well as the tool. And you turn on your computer, access the Internet on a medical site with the question: "Help to cut out appendicitis." Do you understand the absurdity of the whole situation? Even if they answer you, it is worth considering factors such as the patient's diabetes, allergies to anesthesia and other medical nuances.I think no one does this in real life and will risk trusting the life of their loved ones with advice from the Internet.

The same is in the repair of radio equipment, although of course these are all the material benefits of modern civilization and in case of unsuccessful repairs, you can always buy a new LCD TV, cell phone, iPAD or computer. And for the repair of such equipment, at least it is necessary to have the appropriate measuring (oscilloscope, multimeter, generator, etc.) and soldering equipment (hairdryer, SMD-hot tweezers, etc.), a schematic diagram, not to mention the necessary knowledge and repair experience.

Let's consider a situation if you are a beginner / advanced radio amateur soldering all sorts of electronic gizmos and having some of the necessary tools. You create an appropriate thread on the repair forum with a short description of “patient symptoms”, ie. for example “Samsung LE40R81B TV does not turn on”. So what? Yes, there can be a lot of reasons for not switching on - from malfunctions in the power system, problems with the processor or flashing firmware in the EEPROM memory.
More advanced users can find the blackened element on the board and attach a photo to the post. However, keep in mind that you are replacing this radio element with the same one - it is not yet a fact that your equipment will work. As a rule, something caused the combustion of this element and it could “pull” a couple of other elements along with it, not to mention the fact that it is quite difficult for a non-professional to find a burned-out m / s. Plus, in modern equipment, SMD radio elements are almost universally used, soldering which with an ESPN-40 soldering iron or a Chinese 60-Watt soldering iron you risk overheating the board, peeling tracks, etc. The subsequent restoration of which will be very, very problematic.

The purpose of this post is not any PR of repair shops, but I want to convey to you that sometimes self-repair can be more expensive than taking it to a professional workshop. Although, of course, this is your money and what is better or more risky is up to you.

If you nevertheless decide that you are able to independently repair the radio equipment, then when creating a post, be sure to indicate the full name of the device, modification, year of manufacture, country of origin and other detailed information. If there is a diagram, then attach it to the post or give a link to the source. Write down how long the symptoms have been manifesting, whether there were surges in the supply voltage network, whether there was a repair before that, what was done, what was checked, voltage measurements, oscillograms, etc. From a photo of a motherboard, as a rule, there is little sense, from a photo of a motherboard taken on a mobile phone there is no sense at all. Telepaths live in other forums.
Before creating a post, be sure to use the search on the forum and on the Internet. Read the relevant topics in the subsections, perhaps your problem is typical and has already been discussed. Be sure to read the article Repair strategy

The format of your post should be as follows:

Topics with the title “Help fix the Sony TV” with the content “broken” and a couple of blurred photos of the unscrewed back cover, taken with the 7th iPhone, at night, with a resolution of 8000x6000 pixels are immediately deleted. The more information you post about the breakdown, the more chances you will get a competent answer. Understand that the forum is a system of gratuitous mutual assistance in solving problems and if you are dismissive of writing your post and do not follow the above tips, then the answers to it will be appropriate, if anyone wants to answer at all. Also note that no one should answer instantly or within a day, say, no need to write after 2 hours “That no one can help”, etc. In this case, the topic will be deleted immediately.
You should make every effort to find a breakdown on your own before you get stumped and decide to go to the forum.If you outline the entire process of finding a breakdown in your topic, then the chance of getting help from a highly qualified specialist will be very great.

If you decide to take your broken equipment to the nearest workshop, but do not know where, then perhaps our online cartographic service will help you: workshops on the map (on the left, press all buttons except “Workshops”). You can leave and view user reviews for workshops.

For repairmen and workshops: you can add your services to the map. Find your object on the map from the satellite and click on it with the left mouse button. In the field “Object type:” do not forget to change to “Equipment repair”. Adding is absolutely free! All objects are checked and moderated. A discussion of the service is here.

Everything I do at work: computers, automation, controllers, programming, etc.

Amazing nearby!
If they told me in all seriousness that the earth is flat, I would be as surprised as Oleg said that the solar-powered calculator also uses the most ordinary iron battery.

Oleg said that one day his faithful friend and assistant, an accounting calculator like Citizen SDC-888, stopped working. Having opened the case, Oleg was amazed at what he saw inside the calculator. According to him, there was an iron tablet battery installed in the calculator.

The solar battery was simply not connected to the calculator board, from which he concluded that this solar battery was just a props. The internal installation of Oleg's calculator was also surprised - the boards were casually tied to each other with adhesive tape.
Oleg replaced the battery in his calculator and it magically started working again.

I have the same calculator, Oleg told his story because he saw the same device with me.
I was not used to taking my word for it, so right there, under Oleg, I decided to check the veracity of the cruel accusations myself.
Disassembled my Citizen and looked inside.
Here's what I saw there.

I was very surprised by this post.
This calculator is NOT a “solar powered calculator”!
It clearly reads “2 POWER”, i.e. powered by solar cell AND BATTERY.
In addition, measure the voltage on the solar cell when it is turned towards the table with the work surface. to put it mildly, wrong.
>> Maybe in order to work at dusk.
It is for this!