Sharp Memowriter EL-7000 notes storage and printing device repair after battery leakage

In addition to calculators with BASIC and electronic notebooks, Japanese companies released rather unusual devices in a similar form factor. One of them is shown on KDPV after repair.

An interesting feature of the device is a way to distinguish between the letter O and the number 0. Usually, either the zero is crossed out, or a vertical line is drawn inside it. Here, the letter O represents the inverted letter Q. Both on the screen and on paper and on the keyboard.
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The first thing that the author discovered immediately after opening the case: the batteries did not just leak, but flowed thorough. It is no wonder that the device was sold to him as faulty.



And on the back of the board, the electrolyte “consumed” printed conductors in a third of the area.



Neutralization of alkali with oxalic acid.



After rubbing dry and cleaning with isopropyl alcohol. On the right there is a cable that goes to the processor board. Most printed conductors connected to the cable have no conductivity. In other places, too, there were such guides. Some of the cliffs are generally determined visually: the copper has disappeared, the base of the board is peeped out.



But most of the conductors do not see the cliff, it was easier to duplicate them all with wires.



Is done. The author borrowed a nail polish from his wife and covered the wires with it.



More varnish.



Cold soldering of one of the conclusions of the reed switch. The drum with spiral track moves the print head. The magnet on the drum passes by the reed switch when the head is in the middle.



And the head is not one. There are four of them. From the 16-character string, each of them prints 4 characters. The distance that the entire tandem moves in a square is reduced by four times, and the printing speed increases by the same amount.



The tape in the cartridge, of course, has dried out in 38 years. But…



The translator decided to find out the characteristics of the device and found another article . It turned out that the necessary Epson ERC-05B cartridges are still available in many places - Yandex will confirm. I wonder for which modern devices they are buying? There would be no demand - no one would sell them.

The device works in three modes. Typewriter mode allows you to type a 48-character string, edit it, and then send to print as three 16-character strings. So you can print long texts, because when you enter a new 48-character string, it replaces the old one into RAM. In the storage mode notes, the device EL-7000 allows you to save 8 lines of 15 characters each, and the EL-7001 - 40 lines of 17 characters. Any note can be read, edited and printed. Where the seventeenth character is printed, if 16 is placed in their string - it is not said. Finally, in the third mode, the device works as a calculator with or without printing.

But it is more interesting, of course, to fill the original cartridge with a permanent marker.



Go through the battery compartment.





See how quickly everything worked: