Multitech KB-101A Restoration and Mods *NEW VIDEO 6.1.2019*

User avatar
twinrotor

26 Feb 2018, 16:20

Please read entire post for all pics and videos

Project Overview:

This project is a documentation of restoring/modding my Multitech KB101-A. I welcome all discussion and suggestions in this venture. However, I do plan on keeping the original layout and housing. If you were hoping for a complete custom, this is not going to be that kind of build. I've used this keyboard for about 3 months now and plan on using it as my primary keyboard on my moderate duty work machine.

This will be an on-going weekend type project, as I'm going to try to keep the keyboard in service as I work on it. Of course, I will put it out of service if required, but I don't think I will have to with careful planning. Only one aspect, discussed below, would put it out of action for more than a day.

A little background:


Most people will recognize this keyboard as an Acer KB-101A. This keyboard is the Mutitech branded version, built before the Taiwanese company renamed itself Acer in 1987. The keyboard was continued under the same part number, same plastics and the same wonderful blue Alps switches. The only external changes I've found, comparing the two "brands", are the sticker labels and the XT/AT switch being labeled as AT/XT, instead of the numbered switch found on the Acer version.

This keyboard came into my possession by luck. It was hiding in a stack of keyboards I have collected over the last 35 years, but I do not remember the specifics on how and when it came into my possession. I have a vague memory of using it, but I never owned any Multitech machines.. Regardless of how I actually acquired it, I'm pleased I never sent it to the scrap heap. The keyboard also survived many failed storage situations; I lost a lot of my equipment through floods and other moisture issues. I'm also a sucker for giving stuff away to people that have a genuine interest in "old" hardware. Share the love, right?

Quick clean and testing:

Forgive my lack of pictures of this step! I was entirely focused on testing to see if this keyboard survived, also I did not know what I actually had when I rediscovered the keyboard. There is very little information about Multitech on the WWW! I also had not made the connection with Acer until much later, after watching chyros' wonderful reviews on the Acer version. The case shapes are identical.

The keyboard was extremely filthy. so I quickly wiped the surface dust and cleaned the top of the key caps so I didn't get 15+ years of dust all over me. A quick test with my Pentium 100 machine revealed the keyboard working almost perfectly. I then used a DIN to PS/2 adapter and found it worked fine with more modern motherboards with dedicated PS/2 keyboard ports. However, there is an issue I had with Intel's LPC controller, responsible for a single PS/2 mixed port on my current motherboard. After much aggravation with my "dead" PS/2 port, I used soarer's code and programmed a teensy 2, after first trying several generic PS/2 to USB adapters that simply would not work with the Multitech. The teensy has worked flawlessly with no modification with soarer's final firmware release. I have since found a intermittent short in the main cable! I think all my connection issues are due to this, but I like the little converter!

Confirming that the board only had an issue with one key, the comma, I decided to tear the case down, removed the key caps and attempt to clean out the years of dust and potato chip residue. I did snap a few pictures after first removing the top cover. Here are some pics after cleaning the plastics and key caps, as well as the few pics I took before cleaning the key tray:

Image

Image

Image

Image

Cheetos, chips and lots of dust:

Image

Image

Image

Image

Switches were actually protected fairly well by the key caps. I only had one intermittent switch, repaired by simply disassembling it and giving it a shot of air.

Image

Image

Image

The Multitech and Acer share a similar controller PCB with similar part numbers, but there are major differences. The layout is the same, but examples I've found of Acer PCBs have different model ICs. The biggest difference is the missing ROM chip on the Acer variant. The Acer PCB has a ROM header, but there is no installed chip. This might explain my connecting issues with certain adapters, but I do not know these circuits well enough to make that conclusion. Maybe someone else could help explain?

Image

ROM missing from Acer models. The Sharpie mark is a nice touch :) The AMD EPROM is described as an EPROM OTP 64K-bit 8K x 8 150ns 28-Pin CDIP. I found no reference to the first number on the chip, making it feasible it was specific to this use?

Image

Build dates are found both on the plastic base and the PCB. I'm curious when Multitech started producing this keyboard. This keyboard would have been close to the last Multitech branded KB101-A manufactured before the Acer name change. This tray dates from May 4, 1987, while the PCB is either the 25th week of 1987 or Febuary 5, 1987.

Image

Testing the teensy.

Image

Project Goals

Complete tear down is imminent. While it doesn't look terrible, the paint on the metal plate is bubbled where some type of liquid, or just humidity, has mixed with whatever nastiness, lifting the paint. There isn't any scale, but there will be. Rust is worst than time and taxes when not taken care of properly. The PCB looks great from the opposite side and it functions ok, so I'd like to prolong the life of the keyboard as much as possible, while also returning it to a like new state. I'd also disassemble and clean all switches, as long as there are no brittle plastics. The comma is the only switch I have disassembled, but others could be a pain. Anyone experience brittle tops on Alp switches?

I definitely need to do a bit more research and listen to opinions before I bite this bullet as well. I don't want to destroy it. I do have the tools and time, but old stuff can go sideways quick. I do not know what it looks like under the metal and the matching PCB side. Could be carnage or it could be completely ok. I think its superficial now, but will turn into a nightmare down the road.

Need to finalize how I want to deal with the teensy. There is plenty of room in the case for a permanent mount, making for an easy cable replacement with USB. The case has room to get a micro USB plug inside without having to modify the case permanently, and I have a few grey cables in hand. oDecided to leave keyboard and cord intact.]

However, I also have builders boxes in the mail with USB and DIN terminals on the way as well. IF I can find an exact replacement DIN terminated cable, I would prefer this method. It would allow me to use other keyboards, yet I really don't have a need for that. I could always build another teensy converter "box" to have for other boards. I have not looked for another coiled cable yet, so please share sources please! I'd rather not make my own. [Two months later, no package. I was under the impression there was a short in the cable, but it was a junk PS/2 connector.]

The only other reason for external mount would be to utilize the teensy's extra button features. I don't think I could drill any holes in the Multitech case, but a builders box could support whatever I needed. So far, nothing has come to mind for switch use, other than multimedia functions. I do miss having volume control on my keyboard.

My last concern is to retrobright or not. I really don't want to end up with a Zebra-striped case, nor ruin the top and bottom stickers. The case yellowing doesn't bother me that much, but the key caps kinda do. They are yellowed at an angle and they just never look clean. I've also considered aftermarket caps, but it seems not many are made. Again, please point me towards any that I have missed please!

Updates

I'll simply make replies throughout this post as I make progress, as this project will be spread over the next few weeks. There will also be notes left in this post.

I'm open to any suggestions, criticisms, slaps in the face or any other productive or nonproductive input! I am by no means a keyboard guru, but I do have basic electronic and computer skills. My brain does need checks and balances from time to time, so thanks to anyone who helps!
Last edited by twinrotor on 06 Jan 2019, 14:41, edited 3 times in total.

User avatar
Blaise170
ALPS キーボード

26 Feb 2018, 18:26

twinrotor wrote: However, I do plan on keeping the original layout and housing. If you were hoping for a complete custom, this is not going to be that kind of build.
I already like where this is going. :lol:

User avatar
twinrotor

26 Feb 2018, 18:46

Blaise170 wrote:
I already like where this is going. :lol:
Am I missing something? lol

I did find a crack in the upper housing. Trying to find a solution to at least stop the spread.

The teensy has also been "housed". However, I'm not really liking the aesthetics, but its nice to know its not going to get zapped or crushed.

User avatar
Blaise170
ALPS キーボード

26 Feb 2018, 19:01

twinrotor wrote:
Am I missing something? lol

I did find a crack in the upper housing. Trying to find a solution to at least stop the spread.

The teensy has also been "housed". However, I'm not really liking the aesthetics, but its nice to know its not going to get zapped or crushed.
No no, it's just that typically you see people destroy perfectly good equipment just for switches or keys. Here at DT, most of us prefer the old, like the board I am using now:

Image

User avatar
twinrotor

26 Feb 2018, 19:57

Beatiful Sharp! Love the F keys and LED caps. Very nice. Im not super well versed and have not seen a Sharp. Thanks for sharing!

If something is beyond repair, i have no problem with recyling. But i would be rather disheartened to see a fair condition (like mine) keyboard hacked as well. Although, I do find the idea of building a new keyboard very appealing. That's where I am finding something I do not like; 60%. To each thier own, but not for me. But i will not sacrafice an older MX board to try new switches. Ill buy a new 104 key MX mount and hack it up :)

Edit poor grammar
Last edited by twinrotor on 04 Mar 2018, 23:26, edited 1 time in total.

User avatar
twinrotor

27 Feb 2018, 16:49

Anyone know if there is a anti-fungal or shellac coating on this PCB? Was is common for either to be applied on keyboards? I have Heathkit equipment just drenched in the anti-fungal and its no fun to remove (or breath, for that matter).

Also rather disappointing to see soooo many bent pins. This will not be much fun to disassemble.

Image

User avatar
Blaise170
ALPS キーボード

27 Feb 2018, 16:52

Most likely it's old flux you are looking at. Hard to tell from the pic though. Bent pins aren't too bad to work with if you get a desoldering gun. I'd highly recommend one. Use an Aoyue 701A++ myself.

Image

User avatar
twinrotor

27 Feb 2018, 16:56

Blaise170 wrote: Most likely it's old flux you are looking at. Hard to tell from the pic though. Bent pins aren't too bad to work with if you get a desoldering gun. I'd highly recommend one. Use an Aoyue 701A++ myself.

{image removed}
Funny! I have a 2703A. Its cheap, but does the trick! I was really impressed that the gun works as well as it does.

I'm more afraid of getting to much heat and distorting the base of the switch. I've never attempted to remove any before.

User avatar
Blaise170
ALPS キーボード

27 Feb 2018, 17:06

You don't really have anything to worry about. You'll burn the PCB before you damage the switch, and I think at that point you'll realize you're doing something wrong. :lol:

User avatar
twinrotor

27 Feb 2018, 17:10

Thanks for the input.

The lateral force of straightening the pin, plus heat, is what kinda worried me.. I'll just take it slow.

I've done a lot more delicate work with the gun, but that's a bit different with passive components and less heat applied. I am just being overly careful and paranoid.

andrewjoy

27 Feb 2018, 17:32

twinrotor wrote:
Blaise170 wrote: Most likely it's old flux you are looking at. Hard to tell from the pic though. Bent pins aren't too bad to work with if you get a desoldering gun. I'd highly recommend one. Use an Aoyue 701A++ myself.

{image removed}
Funny! I have a 2703A. Its cheap, but does the trick! I was really impressed that the gun works as well as it does.

I'm more afraid of getting to much heat and distorting the base of the switch. I've never attempted to remove any before.
Thats not a de-soldering tool

I got this bad boy on ebay
s-l1600.jpg
s-l1600.jpg (211.11 KiB) Viewed 992 times
THIS is a de-soldering tool :)

Bent pins is a massive issue with alps its bloody anoying, why!!! WHY!!! there is no need for it.

User avatar
twinrotor

27 Feb 2018, 17:44

LOL! I had that (similar) Weller, till it was stolen from me. I still have the "manual" version, turkey baster style, but very similar iron head. It is horrible. I'd rather wick the entire board, than use that manual Weller.

My AOYUE station does quite nice for about 10% of the price, plus it is multi-function; iron and hot air as well. I've used it for about three years now with 0 problems (now it will burn to the ground). However, this is a build thread, not a tool thread.

User avatar
//gainsborough
ALPSの日常

27 Feb 2018, 17:49

Hey man, I fully support restoring this awesome board! Your multitech kb-101a has always been one of my favorite kb-101a's because of the sweet logo it has!

I've done a restoration project on the kb-101a that I first got as well, though I think mine was in a little bit worse condition than yours...

Image

Nonetheless, I fixed it up and it's one of my favorite boards! Definitely take it slow with desoldering. On mine I actually lifted a few pads, most of them were in non-vital parts of the pad and the traces were still able to meet the pin, but there was one that completely lifted. To fix it I scraped away part of the trace-cover (for lack of a better word) that meets with where the pad originally was using a knife to expose the actual trace. I then just used a little more solder than I would have normally used so that the area of the solder covered the scraped away part of the trace and the pin. Switch works just fine. It was the spacebar switch, actually.

One thing you can try that I came up with during my last soldering session was to use a soldering iron tip to apply heat on a bent pin, and use a steak knife to kind of wiggle between the pin and the pcb. Typically the lifting of the pad occurs because there is solder trapped underneath the bent pin that has a strong hold on the trace-pad, so lifting the bent pin upwards will take the pad with it. Applying heat to the pin will help melt the solder underneath it and the knife/razor blade can separate the pad from the pin. I hope that makes sense... I dont' have a desoldering iron, though - and I'm sure that would help tremendously in these situations!

I also cleaned most of the switches as well. Chyros has a good video and taking apart alps switches using some toothpicks, which is what I still do to open mine! They are pretty robust switches, and I've never encountered a top housing so brittle that it cracks or breaks.

Anyway, I hope you don't mind me posting a few pics of my finished project! Maybe it can serve as inspiration for what you might want to do!

Image

Image

Image

Image

Image

Image

Good luck with the project and have fun!!

User avatar
twinrotor

27 Feb 2018, 18:01

Thanks //gainsborro! I don't think you had quite as much Cheeto dust :)

Did your PCB have a coating on the bottom as well? I just didn't touch it with an iron while I had it apart this morning to get a whiff. I'll know once I start, but I really don't want to breath in the anti-fungal. Heard horror stories about that junk.

User avatar
//gainsborough
ALPSの日常

27 Feb 2018, 18:09

I don't know if it was coated or not. I didn't even know to look out for that stuff until you mentioned it in this thread, and I've desoldered a lot of vintage boards for restoration... if any of them were coated, I've almost certainly breathed some of those fumes in >_<
Last edited by //gainsborough on 27 Feb 2018, 18:11, edited 1 time in total.

User avatar
Blaise170
ALPS キーボード

27 Feb 2018, 18:10

A couple observations. Usually the tip of the desoldering gun can be used to bend the lead back. If that doesn't work, a flat head screwdriver with an iron works wonders. When doing any soldering work, I highly recommend an exhaust in order to keep the air clean. You can buy professional versions from brands like Hakko, but I used a $20 dehumidifier that came with a charcoal filter. This not only prevents you from breathing in flux (my nose is burning just thinking about it) but if there are any other chemicals being vaporized, they should get sucked in to the exhaust as well. The $30 I spent on dehumidifier and filters is well worth preventing lung disease.

User avatar
twinrotor

27 Feb 2018, 18:35

Fumes and how they affect health is a debate for another thread :)

//gains, you would have known if it was an anti-fungal. It has a very unique smell. It is also WAY more toxic than any lead or flux fumes you might get a whiff of.

My projects and repairs are generally fairly small, so I'm not too worried about ventilation. I can always use a fan and a window with this keyboard, if I find it overwhelming. I'll know soon if it is anti-fungal.

I think I need to worry more about the 30 years of asbestos brake linings I've dealt with throughout my career :)

andrewjoy

28 Feb 2018, 01:21

Lead solder is in no way dangerous ( unless you eat it or somthing) , the lead is not vapourised

the flux is the nasty stuff and the flux for lead free solder is was worse

User avatar
twinrotor

01 Mar 2018, 02:14

And now for something completely different....

Since my keyboard is going to be down for 10 hours to 10 days, I decided to try and find some kind of mechanical board to substitute for the Multitech while it is torn down. A few searches on CL and FB yielded little, but generally keyboards made in the last 5 years. I found the most appropriate board, based on price and MX mount switch mounts. I'd like to tinker with other switches in the future. I am being vague about what keyboard it is, due to one key that messed with my mind.

Little old lady listed the keyboard as "too distracting with lights". I will assume she was unaware you could turn the lights off.. She said used little (more about that below) and was asking $50. I offered $20, she accepted. She handed me the keyboard in a linear non-RGB Logitech mechanical box lol I think the noise of these fake MX blues attributed to her selling it as well.

I pulled all the keys to clean. One of the first I pulled out of the bucket to wipe down was this guy below. I looked at it and had no idea what it was... I had all keys back in place beside four others before I realized what letter it is. The font is disgusting on this keyboard, but I'm not one to make a full review. Other people are better at that than me.

Image

So much for "little use". Nasty! Can't even trust little old ladies these days :)

Image

It did clean up easily and nicely. Not sure of the switch brand/model?

Edit: They are apparently Gaote OUTEMU switches

Image

In all its shitty knock off MX glory, the Motospeed CK103

Image

In all honesty, this thing is better than any of the dome boards in my possession. The only other keyboard I have on hand is my model F that came with my 5150. I'm not going to use it lol. I've seem some promising MX mount switches recently that I'd like to try, so I think this aluminum plate open chassis is worth the $20. They generally sell for $59, and I don't think I could encourage buying at that price. There is quite a bit here for that money, but there are more caveats at that price range. The key caps are terrible, the switches are fair at best, however the base and plate (hopefully PCB too) seems to be adequate for me to play with.

Sorry for being a bit long winded, but I did want to get some WPM on this keyboard. See if I'm going to be able to stand it for a super long period of time. One big nag is how light and scratchy, compared to my blues. I have long fingers, so i "lean" the caps in keystrokes because I drag my fingers. These bind and are scratchy. My alps do no such thing. The alps are also noticeably heavier and a bit deeper on keystroke. I am getting a few ghost strikes, but not as bad as I thought it would be.

User avatar
twinrotor

03 Mar 2018, 16:27

So it begins. These MX clones are driving me nuts, so I'm going to try and get this project done soon!

The part I hate the most. Pulling caps. You can see where I bent the "power" LED. I really don't want to remove those guys, but I might have to. I don't have a board holder to keep from smashing them, but they are cut to the right length to line up with the top cover.

Image

Nasty... See what looks like hair under the paint? I can see oxidation as well :(

Image

Image

Image

The "strain relief"

Image

You can see the coating on the PCB a little better in this pic. Its just flux; alcohol took it right off, no funny smell.

Image

Hoping there is no de-lamination going on here.

Image

Solder is easy to remove. See video below.

Image

Free!

Image

And here is to number one of 101. Love that old logo. Notice the pins are staggered, as the holes in the PCB are drilled that way.

Image

Image

Short video. Sorry for the quality. Lighting in here sucks for cheap cameras.

User avatar
//gainsborough
ALPSの日常

03 Mar 2018, 19:04

awwwwww yeah!! Restoration time! Have fun, my man!

User avatar
twinrotor

04 Mar 2018, 13:57

//gainsborough wrote: awwwwww yeah!! Restoration time! Have fun, my man!
Most definitely!

Pulling caps really is my least favorite thing about any of it. I've broke two wire type and one chap plastic puller. If anyone can recommend one that's not going to pull the wires out of the handle, please LMK! Hopefully I won't be pulling these caps again, but I'd like to have one in can count on, just in case.

Did not have much time yesterday, so what I posted is where I am in the project. I'm going to sneak over this morning and at least free the plate so it can get treated and painted. Most likely going to aircraft strip, rust treat, I've got a friend with a 25" auto feed belt sander that it will be "milled" with as well to insure I get a nice flat plate to start refinishing.

I'm also going to use POR15. Look it up if you are unfamiliar. Very expensive, but one of the best options here, besides powder coating (which might happen if I can get it laid thin enough).

User avatar
purdobol

04 Mar 2018, 14:30

twinrotor wrote: Pulling caps really is my least favorite thing about any of it. I've broke two wire type and one chap plastic puller. If anyone can recommend one that's not going to pull the wires out of the handle, please LMK! Hopefully I won't be pulling these caps again, but I'd like to have one in can count on, just in case.
My go to method is 2 butter knifes. Prying caps from both sides (left and right) simultaneously.
Feels like I have more controll that way. Never liked keypullers. It's way slower though.

User avatar
twinrotor

04 Mar 2018, 16:21

I used a similar method with two plastic spudgers. Works fine, but you do occasionally have to put pressure on an adjacent slider.

User avatar
Blaise170
ALPS キーボード

04 Mar 2018, 17:02

I've never pulled the wires out of mine even on extremely tight keys. I have a WASD, Varmilo, and Keycool as well as a bunch of plastic ones.

User avatar
twinrotor

04 Mar 2018, 22:54

Blaise170 wrote: I've never pulled the wires out of mine even on extremely tight keys. I have a WASD, Varmilo, and Keycool as well as a bunch of plastic ones.
I have bad luck? I don't remember where they came from, but one is super old and the other was off either eBay or Amazon.

Now, these key caps and switches are tight. The caps on the Motospeed almost fall off by themselves. I can easily pull them off with my fingers.. Not on the Multitech. So ? Hopefully this will be the last time I have to pull the caps for a looong time.

At first, pretty smooth run with the gun. Around 50 keys did not have bent pins. Those were a breeze. The bent pins, I used a similar technique as demonstrated in the video, but I made sure to get every bit of solder as possible with the vacuum. There were only 5 pads that lifted, only the width of the pin. So they will solder back in straight, no problem.

This is the NUM pad. The left two switches where bent over, but the other's pins were straight. Most keys in the middle of the PCB were straight, while switches at the edge had bent tabs. I'm sure its to allow for better alignment while they/the machine populated the board.

Image

After straightening the pins, I pull as many switches as I could by finger. The small return catches on the lower switch housing make it pretty tough on the 'ole digits. Out came my "magic pliers" (Knippex adjustable, my favorite pliers of all time) and just some gentle rocking freed the more stubborn and caked in switches. The Knippex are easy to control and were adjusted just so they would bottom out before even marking the switch. Worked out nicely.

Image

The one that got away!! F11 was the only key that decided it did not want one of its pins straight again. Luckily, it broke off flush with the PCB, so remount will be no issue.

Image

All done. I was relieved to no seepage through to the PCB..

Image

Image

Unfortunately, the plate is bent. It is also pressed from the factory in an "S" shape. One lip pointing up, one pointing down. So no auto feed belt sander. The rust is superficial, so hand blocking it will be fine, after a dip in stripper. It looks like something was sat on top of the keyboard at some point in time. I think I can slowly work the bend out. The PCB is straight, even holding it at each end, putting all the stress in the middle. No cracks that I have seen, but I still need to go over the PCB with a fine tooth comb. I might be replacing some passive components as well. Mostly the few caps it has.

You can see about an 1/8th" gap. The ends of the plate are on the yellow line. It seems to be bent on one axis only as well, which is a relief. Its also worth mentioning that I did not notice this until it was apart!

Image

Now to the unfortunate instance of me making a huge mistake. The guide retainers shown below simply clip in. To get them out, simply push with your finger on the tapered end and out it pops. After the first popped out in my hand, which had there to catch it, I proceeded to just poke the second one, without my other hand to catch it. Off it went to that magical place were socks go... Seriously, I kinda heard were it hit, but I looked for almost an hour to no avail...... :( Please tell me I can buy these!

Image

For those who have hung in there, through my ramblings and babbling, here is some dirty alps porn

Image

We're having terrible weather, so it will be until next weekend at the soonest before my wife can paint. I will get everything nice and clean while I wait. I've decided to do the key caps in peroxide. Again, waiting for sunshine and a little warmth.

I've had a second thought on paint as well. I think the POR is going to be too thick, even if I reduce it and spray it. So after the wife and I discussed a bit, she's thinking of just getting an etching primer and a decent acrylic base automotive paint. Super easy to work with, plus we can get it charged into rattle cans. I'd rather not drag out all our painting gear; its stored, as my wife has been too sick to do real body work.

Edit: Typos, typos, and more typos.

User avatar
twinrotor

05 Mar 2018, 02:42

After some thought, I think I'm going to follow //gainsborough's lead and paint the back plate a color from the label. Its a dark gray, similar to the same dark silver/gray used in many electronics. Didn't have my good camera, so the colors are off a bit

Image

Image

andrewjoy

05 Mar 2018, 11:02

As this is such an awesome board i would go whole hog on fixing them broken pads.

This video is long but gives you everything you need to fix a pad.

https://www.youtube.com/watch?v=vx50YtEC2S8

If that is too much i would use very thin enameled copper wire and put some conformal coating over it

User avatar
twinrotor

05 Mar 2018, 11:15

If the damage was greater, of course I would repair. Since no more than a pin width of trace was lifted (about 10% of pad total area), I'm not too worried about it. Most of the 5 pads affected do not even look damaged.

My main concern now is finding one small stupid stabilizer mount....

andrewjoy

05 Mar 2018, 11:17

twinrotor wrote: If the damage was greater, of course I would repair. Since no more than a pin width of trace was lifted (about 10% of pad total area), I'm not too worried about it. Most of the 5 pads affected do not even look damaged.

Fair enough , i would then just scrape a bit off the solder mask on the trace leading away from the pad to give you more surface area.

Post Reply

Return to “Workshop”