Welcome back to part three of my restoration and adventures with an NEC PC-8201a vintage computer circa. 1983. Let’s get to it!
It’s actually not that grungy to look at. Sure, a minor scuff or two, but from the looks of it, this unit is actually quite clean.
So, let’s get it apart and get everything shiny.
Open the Case
Four screws hold the case together. They come out without any bother; nice that there are brass ferrules that they mate to. None of this self-tapping into plastic.
Once the back is open, we’ve got a few more screws to free the keyboard from the top case.
And we have to carefully disconnect the keyboard connectors from the mainboard. And eventually remove all boards from the case.
There are two sturdy metal rails that reinforce the keyboard board. These help if you’ve got a tendency to pound the keyboard as I’ve seen many two-fingered-typing journalists do. Of note, the Tandy Model 100 only has one metal rail, the other is plastic.
Ah, There’s the Grunge
Lifting the keyboard out of the top case shows the fabric top layer used to keep crumbs and other debris from the circuit board.
Interestingly, there’s also a soft sponge layer covering the switches corresponding to the function keys (F1 — F5). This is also absent from the Model 100 and does soften the click sound from those keys.
Removing the fabric reveals the circuit board. It’s an ALPS keyboard, which is a very good maker of keyboards, back in the day and even today. ALPS keys are much sought after by mechanical keyboard enthusiasts. And it’s a little grungy.
Carefully remove the other circuit boards and the LCD display module and set them aside.
Plucking the Keys
Using a keycap removal tool is essential as you don’t want to be prying and applying uneven force against the aged plastic pieces. Even so, I did have a couple of the key retaining clips break off a small bit when I extracted the cap — but they seemed fine in subsequent testing.
Some keys (Shift, Space, Enter, etc) also have a metal support bar to reinforce commonly used keys. These bars just clip into the base of the keycap and must be carefully disengaged before the keycap is free.
The triangular arrow keys, the function and stop keys are just interesting configurations of the same ALPS keys, nothing custom or stripped down to save a few pennies.
Into the Bath
I’d previously restored an IBM Model M keyboard and learned a bit about cleaning keyboards. Keycaps all go into a warm bath — basically a jar with warm water and a squeeze or two of Dawn dish soap. They stay in the bath for a day or two, stirring once or twice a day.
After removing the LCD and main circuit boards from the top and bottom cases, both of those cases get their own warm-to-hot bath in soap (maybe 30 minutes) followed by a vigorous scrub and a good rinse to remove all the soap/grime residue.
Back to the keycaps
After they’ve soaked for a couple of days, it’s time for a good scrub. This is kind of tedious, but rewarding. The soak got rid of most of the grime and a few passes over each face with a toothbrush under running water got rid of the rest. Follow with a final rinse.
Out to Dry
The cases were easy to dry with a towel, then stand overnight in front of a fan (on low) to ensure they dried.
To dry the keys, just lay them out on a towel in front of a fan (on low). Remember to flip them in a few hours to make sure the insides of the keycaps also are dried.
I left them for a few days, flipping daily, just to make sure they had dried out completely.
Cleaning the Soft Bits
The fabric crumb-catcher is actually quite sturdy. To clean it you just give it a good soak in dish soap and water, then gently brush while wet. I hung mine on a towel rack to dry over night.
The foam Function key cover was gently soaked in the same dish soap, then carefully rinsed and set to dry with the keycaps. Be very careful with the foam strip, it’s quite thin and I imagine easily torn.
Really it’s just the reverse of the disassembly process. Make sure to remember the position of every key (heh, take a photo of the keyboard BEFORE you pull off all the keycaps), and carefully replace the support bars under the Space, Enter etc, keys.
Of course, put the Crumb Protection fabric back on BEFORE you start replacing the keycaps — something I remembered after about 10 keys in.
Then carefully remount the boards back into their respective cases, close it up and you’re back in business.
Or so I Thought
After I’d gotten the board back into the case, I found this small plastic sheet. I didn’t really remember where it came from, and had to look at my pre-disassembly photos to find it.
This little sheet protects the keyboard cables from being scraped and cut by the sharp solder ends of the keyboard (you can see it between the connectors and the PCB in the photo to the right). I think there was a little adhesive on one end of the plastic shield, but it wasn’t tacky now.
So I cleaned it, and used some water-soluble gluestick on that end, and after comparing the position to my photos, glued it back in place. It seems to have worked.
Then it was a simple matter to put the two halves back together. Power it up and enjoy the squeaky clean feel of a new-ish computer!
Next up: replacing the onboard memory protection battery and a look at the REX# enhancement chip.
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