I recently bought this portable Soviet Mikrolab KR580IK80. The chips are by design exposed, as it was a training computer, and although it is housed in a carrying case, it is extremely dusty as can be seen in the following picture.

Dusty Mikrolab in working order

While it is generally functional, it has exhibited some unexpected behaviour, and I wondered if it might help to clean it. However, for obvious reasons I am afraid of doing more damage than good. For this reason I want to ask to what extent the following common ways of cleaning motherboards would be safe for this computer.

  1. Compressed air
  2. Specialist contact cleaner
  3. Isopropyl alcohol

The board looks like pressboard, which is essentially cardboard, and liquids don't do that any good.

Clean the switches on the front, and the area at the crystal at the left back first. If that fixes the glitches, don't clean the other parts.

  • Which exact area at the left back do you mean, and why would cleaning this area in particular help?
    – harlandski
    Mar 28 '18 at 11:19
  • The area around the crystal. Mold around the crystal oscillator can lead to additional capacitance and leakage and may render it unstable.
    – Janka
    Mar 30 '18 at 20:36
  • How do you imagine they would have manufactured the board other than by aqueous etching? Phenolic-resin / paper PC boards are a far cry from "cardboard" Apr 2 '18 at 3:15
  • 1
    Manufacturing a board is a controlled process. Chemicals are defined. Time and temperature are defined. The board is pristine before etching. It is cured after etching. There is no wear from heat. Boards found bad after processing are thrown away. All this isn't the case here. You cannot throw away the bad "cleaned" board. You use a mostly undefined cleaning fluid "until the mold comes off". You don't have the "antidote" to cure it after cleaning. Simply rinsing it with water will give you even more headaches. And so on and on and on…
    – Janka
    Apr 2 '18 at 15:25

Hard to tell anything without a hands on check of the materials.

With simple PCBs (just with IC and alike) I usually use regular water and soap, often in a kitchen dish washer. Rinsing it afterwards with demineralized water is a good idea.

If there are other parts on the board, stickers or markings, one needs to be more careful.

In any case, pressured air and next a wet rug will already clean 90% of all dirt.

I would abstain from any specialized cleaners and/or alcohol, as they usually solve many paint/markings. Especially of 'non-standard' kind - here meaning boards made by different porcesses/materials than common in 'the West'.

BTW: Awsome find. Something I'd love to study.

  • Yes, I'm pleased to have got a working one - and there's a really good book to help me study it. Is it really safe to use a wet cloth to clean it? I suppose it then needs to dry out thoroughly afterwards?
    – harlandski
    Mar 24 '18 at 19:16
  • 1
    Sure it is. Ofc, not soaking wet, but still, water doesn't harm PCBs or chips. Also no special drying needed. Just wait a bit until it seams dry. Computers neither work with high voltage nor very low current. At least not stuff that old. (And if yo uever come across another, give me a hint)
    – Raffzahn
    Mar 24 '18 at 19:45
  • 1
    Btw I've posted a short video of the machine in action on YouTube. Search for "Soviet Spy Computer" (marketing trick!)
    – harlandski
    Mar 31 '18 at 13:28

Step 1: pressured air (inflow and/or outflow) with narrow nozzle. Should clean "unbound" dust out of the board and under the chips. Be very careful with buttons. I would not advise disassembling them as old plastic may crack;

Step 2: use shave brush to clear "bound" dust, and then use vacuum cleaner again to remove remainders. While using brush, be careful not to perform too sharp moves as bristle may get between pins or plastic parts and by tearing it off you risk damaging the components. Be gentle and use the bristle along its axis rather than perpendicular.

Step 3: use vodka. No, on the board. Do not use dissolvents. You can use isopropyl alcohol, but testing it on some area which is not exposed (e.g. on the bottom of the board). Aged materials (including silkscreen and colored polygons) may be subject to removal with spirits, thus if possible do not use spirit at all.

Step 4: keys can be cleaned by the soap and water, but that would be uneasy without pouring them inside the buttons. Be very careful, and use wet sponge a dozen of times on every button (instead of pouring everything into the water and then drying).

it has exhibited some unexpected behaviour

Cleaning may help here, but if issues continue after cleaning you will need to apply electronics specialist knowledge to find out the issue. However what you can definitely do after cleaning - taking magnifier and checking board and its components inch by inch looking for damaged conductors, cold solder joints and other damages.

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