Recovery Electronics IM-22

image from wikipedia

Hello Habravchane! I am a 2nd year student of TUSUR. I would like to tell you how I was engaged in the restoration of the cult game electronics IM.
At one time, I did not find such devices as electronics IM, 8 bit computers and the time when everyone was assembling their computers on a crush. Therefore, I wanted to get hold of the device of those times. Prices on sales sites did not inspire me and I had to invent something else.

Some time ago, I got into the hands of the Electronics IM-22 (funny football players), when batteries were inserted into the device, to my chagrin, there was no image, there was only sound. The breakdown consisted of dried conductive rubber bands, and since then my knowledge in electronics was not great, the toy was safely disassembled, and all the details were confused.

found original conductive gum

And a year ago I found in my boxes a whole display (IZHM1-42) with polarizers (used by me as a child as an unknown thing, which became dark at a certain turn), buttons for selecting the game mode and like a native piezo squeaker.

Display Photos

A little googling, I found the instruction manual, but the scheme in it was poorly scanned. I had to look further; and only after a long search was it possible to dig out a service scheme with oscillograms in good quality. The heart of the device was found on the Chipdip website: KB1013VK1-2, immediately ordering, began to raise a fee in haste.

scheme from the original document

At first I thought about dissolving my own version, but quickly changed my mind in favor of simply copying the original board. Having found the photos started copying. The hardest part was fitting the footprint size to the actual chip size and display size. The game mode selection buttons decided to leave the original, and make the direction selection buttons based on the SMD clock buttons. The power scheme was also original. When the board was divorced (it turned out not the best, but for the preliminary version it will go), she went to turn into a real one with the help of LUT. Nothing particularly, vias using wires. I regretted that I made small contact pads, because after drilling they partially collapsed.

Printed circuit board. front view

Printed circuit board. back view

Original game board

After soldering all the components, everything was immediately turned on, and I heard sounds from a tweeter. Then he was pressed with the help of new gum (conductive gum applied from the broken character indicator HD44770) display, and even some image appeared!

due to weak and not uniform compression the image is not full

current gum from character display

It is time to figure out how to attach the display to the board. A method was chosen to press using a fiberglass frame. No sooner said than done, it turned out a bit crooked. Made the necessary holes for mounting thick wire. The most difficult thing was to accurately relate the contacts on the display and on the board (in the case of an inadequate connection, the wrong segments were burning and very dimly).

pressure frame

Glued buttons on the hotmelt.
One of the modifications was in the processing of food. It was very inconvenient to use two 1.5 volt tablets, since there was no normal holder. I decided to use a resistor divider (2 resistors per 100 kOhm, current 0.000015A) and a 3 volt battery. Currently it works great.

Old version

The final option. Back view

The final option. Front view

There is one problem: on the diagram with all the elements, when the “clock” of the game was pressed, the game was turned off. At the moment, no action was taken. He also noticed that the device is very sensitive to accidental closures of the tracks with his fingers.

Weed the board and set up the elements in the university dormitories, processing (sawing, drilling) in the laboratory.
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I am pleased with the result, especially surprised by the display that has survived for so many years (not lost its clarity) and the fact that one can still find such ancient chips without problems, which also work.

ps: maybe someone will be interested in the scheme, I hope not to violate the copyright, because I do not remember where I found it.

Scheme