How to Clean MSX Computers?

Por tech

Supporter (12)

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15-12-2019, 02:08

I've recently acquired 2 abandon MSX computers (Sakhr AX-370 and AX-200). They need lots of cleaning in and out. I'm wondering what would be the best and safest way to clean them?

I tried to de-cab keyboards in both computers, but the keys did not come out. I refrained from using extreme force because I'm not sure whether the keycaps are detachable or not.

It thought of taking the motherboards off then submerge the keyboards in a watery solution, but I'm not sure if this would be safe.

Any suggestions please?

Thank you.

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Por hamlet

Scribe (2866)

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15-12-2019, 11:00

That's the way I prefer most:

Por Wild_Penguin

Hero (584)

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15-12-2019, 11:17

First, a few questions: how dirty are these computers actually? What is wrong with the keyboard(s)? This will determine how you should clean them and what makes sense.

You can use general PCB cleaning instructions to clean the PCBs; there is nothing special in MSXs in this regard. For example, one of the first Google hits is this: https://www.sfcircuits.com/pcb-school/clean-pcbs-ultrasonic-...

Rule of thumb: use "dry" methods first, such as compressed air (regular vacuum cleaners might create large static electricity potential, so I would stay away from those)! If you can not get a good enough result that way, then you may try something wet. Don't use solvents, unless the PCBs are dirty with something that really needs to be removed and requires some solvent. Also, IIRC (?) these computers have plastic parts which are not easily removable (around the cartridge slot). In case you are going to expose the PCBs to solvents (such as acetone) make sure (test somewhere where it doesn't matter) the plastics can take it. However: don't use them to clean if it is not absolutely necessary. Cleaning agents / solvents can do more harm than good, such as remove protective laquer from the PCBs.

IMO using regular tap water (at least in areas where tap water is not too hard) can be used to rinse the PCBs, but many sources say you would be more safe with de-mineralized water, though. But you need to make sure they dry all the way before re-assembly (use a well-ventilated dry place, perhaps with a little bit of steady heat if you are impatient; for example, I've used the lower step of a Finnish sauna; those who are not familiar with one, a Finnish sauna is a dry place unless someone throws some water on the stove, and the lowest steps are perhaps around 40-50°C - depends on the sauna though).

As for the keyboard: I presume these computers have a very similar keyboard to the AX-350(II). If that is the case, see this thread.

You should be able to get to the membranes easily and be able to clean them; in case the keys actuate properly (which was not the case in my AX-350II), there should be no reason to dismantle the mechanisms, as the problem must be in the membranes in that case.

My AX-350II keyboard was practically filled with sand and dust. The key mechanisms (and caps) do come off but you need to be careful, as it is very easy to break them unless you know what you are doing. See the pics and instructions linked in that thread. I don't think submerging the keyboard parts will do any good, you really need to take the keyboard mechanisms apart in case there is extra stuff inside the mechanisms.

EDIT: LOL@Hamlet

Por Meits

Scribe (5733)

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15-12-2019, 19:13

If I receive a computer that looks OK, I leave it like that. There are no fans so don't expect the inside to be dirtier than the outside.
I do like to clean the outside as good as possible, so the machine has to be disassembled. Most of the time key caps are easier pushed out from the inside than pulled out from the outside, since you can squeeze the notch that keeps it at its place.
I do not retrobrite... I've seen people have great results, but seen failures as well... Also am I sceptic about how long the effect lasts. Some youtubers who do retrobrite found out that work of a few months ago was more yellow than the thing they just did.
If the machine is quite disassembled, I handwash all the visible plastic with just warm water and good eye for detail. Take time, it's worth it. Ofcourse, it needs to dry before you reassemble the thing Wink

Quite important while disassembling a machine you never opened:
1) take pictures of your steps.
2) keep screws together and write notes where they below. Wrong screws might look bad, but longscrewing might kill stuff.

Por Wild_Penguin

Hero (584)

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15-12-2019, 19:48

I agree with Meits. Unless there is absolute need to clean insides, I'd just clean the outsides too and leave it at that (a badly working keyboard is a good reason to open one up). AFAIK these machines don't have suicide capacitors inside, and those which have a backup battery, use AAA batteries.

Also, with these machines they may be mostly held together by plastic tabs instead of screws. Be careful with the tabs, they are easy to break! That's one other reason to not open these without a clear need, as even with instructions it is difficult not to break the tabs with these machines! Look at CX5MII service manual for how to open AX-200 (from pictures online looks like it is the same frame, but could be different, too; couldn't find accurate pictures of AX-200 case).

The AX-370 looks different, though, so the CX5M service manual (which can be used to see how to open AX-200 or at least AX-350), and those tips in the link I posted above do not probably apply to it, at least not accurately.

Por Meits

Scribe (5733)

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15-12-2019, 20:32

Oh yes, if it's closed with notches: Do not use a screwdriver to pry it open. A plectrum or creditcard like item will do the job.

Por wbahnassi

Resident (48)

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16-12-2019, 00:04

The Sakhr AX-170 I recieved was a complete disaster, with spiders and bugs inside along the clumps of dust and dirt. Every key you press never comes back up. I disassembled the poor thing down to the smallest spring and rinsed the keys in soap water. Rusty parts submerged in white vinegar then rust brushed away. I didn't wash any PCBs though.. just used a compressed air can to blow off dirt in hidden kinks and used a brush with alcohol on parts with dirt stuck on them.
It was a very fascinating sight once it was all re-assembled. Almost new!

Here are some pics of the process:
https://www.instagram.com/p/B5yX4AuguiY/?igshid=1lpbjmdgyora4
https://www.instagram.com/p/B50Y1tfgjQT/?igshid=1s37t716c1i69
https://www.instagram.com/p/B52w6QNgc6N/?igshid=v3rwe7igp0vj

Note this machine uses screws to hold up the chassis. Other machines that rely on plastic clips require much more care as others mentioned. Usually the damage is irreversible.

Por gdx

Prophet (3216)

Imagen del gdx

16-12-2019, 02:33

It's important to open a new received MSX to clean a little inside because you can check potential problems at the same time (swollen capacitors, leaking battery, oxidation, improper modifications, traces of old liquid spilled, etc.). Also like wbahnassi I often found dead bugs inside.

If you are methodical and patient, you can clean the PCBs and case parts one by one in the shower with dishwashing liquid and a old toothbrush. Rinse well and dry well (watch out for small corners, variables resistors and copper wire coil). It may take a few days for corners. Use kitchen paper to dry faster, taking care that it does not tear on the tips of the components. Do not clean keyboard membranes (the tracks are very fragile), variables resistors or transformer. Avoid wetting connectors and daughter boards in metal enclosures.

If you find rusty metal parts inside, you can use anti-rust which protects by blackening the rust.

Por tech

Supporter (12)

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16-12-2019, 03:39

Thank you guys for the greate replies. For sure I'm going to make use of the ideas and tips mentioned here and linked to.

I'll be taking pictures as I'm proceeding with the cleaning and will post them here. The pictures of course won't show the helper suggested by @hamlet Tongue