IBM 3278 Beam Spring restoration

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12 Sep 2018, 20:25

We had several Workshops already on how to restore beam spring keyboards and I learned a ton to get my keyboard to the point it feels like a fresh piece of hardware. Thanks to all, especially tron, who had to answer many questions during the process.

Let’s begin
This is what I started with; an IBM 3278 full size board from 1977 or 1978 in the original un-restored state.
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After functionality tests (including a xwhatsit modification), I recognized wobbling keys and that the typing sound wasn’t as great as I have heard them in some videos. So, I decided to restore it properly…
What is needed to restore the keyboard fully (including the key-switch-cleanup and foam replacement)?
While I got great tips from tron, I wanted to share his list of supplies that you need:
* 15mm Steel Hole Punch
* Paper Towles
* 2mm Craft Foam (I used EPDM foam band with 100mm width and 2mm thickness and adhesive side)
* Tape Measure
* Scissors
* White Marking Pen
* Heat Gun or Hair Dryer
* Containers for The Switches and PCB
* Rubber Gloves
* Work Bench or Table
* Mild Soap and Wash Bucket
* Micro Fiber Wash
* Paper Grocery Bags for Trash
* 3M respirator
* Goo Gone
* Guillotine Cutter
* 3M Acid Free Double-Sided Tape
* Isopropyl Alcohol (really important)
* TIME (take your time with this so you don't have to start over)
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Disassembly of the keyboard

Taking a Beam Spring Keyboard apart is very straight forward. Remove the bottom screws on the case, turn it around and lift of the outer case. You will end up with a view like the first picture.
Next, remove all keycaps using a wire-keycap remover.
The plastic shield beneath them is most likely at a state that you can’t re-use it. In all fairness, it isn’t really required anyway. Remove it carefully. You can also get rid of the initial dirt and plastic shield from the keys.
This is what you likely will have after the first step:
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Get two thicker books, place them so far apart that edges of the keyboard plate will fit. Turn the keyboard (plate with key switches) upside down and look at the underside. There are 6 screws you have to remove.
Be careful when removing those screws. The keyboard might be slipping off the books and switches can dislodge. Once you have it open, you will see something like this:
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Remove all individual key switches by carefully wiggling them out. They should get out fairly easy. Place the switches on a cardboard or box and try to keep them in one piece (not a big thing if they fall apart, we will dis-assemble them anyway later on).
If you’re as “lucky” as I am, you will have a completely rotten foam that is looking like this:
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Put the switches away (we will come back to them later), as we have to concentrate on the sad situation in the switch-plate first.

Step 1: Remove the plastic gasket strips
The plastic gasket strips are the ones which have holes for the screws in on each top ridge. I could easily remove them by slowly pull on them. Make sure you don’t rip them apart, but if they contain a ton of goo – don’t worry. Put them aside for now.
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Step 2: Remove the two plastic separators on each side of the switch-plate. They are only clipped in and can be pulled away easily.

Step 3: Clean the switch plate (get rid of the foam)

The foam originally was on top of an adhesive plastic strip. There are two ways to remove the foam and strip. Either way, get gloves on first (believe me).

Either you use a heat gun and remove the plastic strip together with the rest of the foam (which would be the preferred method) or you do it like I had to do it (the foam was too much dissolved already).

I first removed the foam using a small palette-knife. Look at the picture and get disgusted. This was not funny. After I removed the black foam, I went with a heat gun. With the same palette-knife, I could remove most parts of the plastic strip underneath. Even when I was finished, the switch-plate was still full of goo.
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Use Goo-Gone and apply it for 30 minutes. Let it sit and yes, get new gloves before doing so. I had to apply Goo-Gone two times. Do the finishing touches with alcohol and rinse it finally with a lot of water. At the end you should have a switch plate that looks as shiny as this:
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Step 4: Back to the plastic gaskets
To get rid of all the glue and dirt from the two strips, place them in a bath of Isopropyl Alcohol. Make sure they are completely soaked for at least 20 minutes. After that, take a cloth and spend a lot of time and effort to make them as clean as possible.

Congratulations at this point you have already reached a point where it starts to get a bit easier and less messy. Put away all parts and concentrate on the Beam Spring Switches.

Beam Spring Switch Restoration

The switches are expensive, please work on them only, if you have enough time at hand.

Get 5 or 6 boxes ready for the parts of the switches. Switch housing, white slider with beam spring, coil and metal stem, O-ring, Fly-Plate.

Below is a picture on the different parts of the switches. I will explain how to take them apart properly.
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Taking the Switches apart:
There are multiple ways described to take the switches apart. For me, the easiest method was a plastic box which could be taken apart. I drilled a hole into one end that had the diameter of 10mm. This box is only to get a better grip and limit the possibility of damage to the switch (yes, they are expensive).
Now, place the switch in the one half of the box, so that the metal stem and O-Ring are on the outside and the rest of the switch on the inside. Then take pliers, grab the metal stem and pull on it (sometimes as hard as you can). The stem will slide out and the whole switch can be disassembled. As I had to do this about 90 times, I spent half a night on this task. Next, put all the different parts into the various boxes above.
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Cleaning the Switches:

Plastic Switch Housing:
I put the plastic housing into a bath with mild soap for two days. After that, I cleaned them with a used tooth-brush and clear water. At the end, I put them in an Ultrasonic cleaning bath and finally rinsed them in demineralized water.
Dry them gently and let them sit on a towel for 24 hours.

White slider:
The white sliders accumulated dust and some rust as well. I had to clean them carefully with a tooth brush and mild soap water (look for the beam spring so you don’t damage it).
After the soap water, I flushed them in normal water. Finally, I put them in the Ultrasonic bath and rinsed them in demineralized water.
Dry them gently and let them sit on a towel for 24 hours.
Coil de-rusting and cleaning (+Metal Stems):
Some of my coils have not only been dirty, they also have accumulated rust. Even, if you don’t see rust on your coils at first sight, the de-rusting is super important.
First, clean the coils in mild soap water and make sure that they are dried right after the bath. I cleaned the metal stems at the same time but also used a brush to get rid of the plastic shield sticking to it.
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Put about 25mm or 1 inch of Evapo-Rust fluid in a plastic box. Add the coils, stems and space bar wire to the bath and leave them in there for at least 30 minutes. I left them in for several hours. I was amazed how much the coils did change during that time (for the better).
After the evapo-rust procedure, I cleaned them with demineralized water and let them dry in the sun.
After they have been dry, I put a layer of Ballistol on the parts and let them sit for a day before I used a paper towel to get rid of excessive oil.

The O-rings have been dirty as well, I cleaned them with Soap-water and put them into the Ultrasonic Bath.

I only used some alcohol to get rid of some of the dirt, but did not bath them or anything else. Be very careful with them.

After the procedure I assembled the switches again. This is super easy to do. First take the white slider and clip in the fly plate at the bottom. Then give it a push and the fly-plate should snap up. Put it aside and grab the black switch housing, put the coil on top where it fits in and then drop the O-ring into the middle of the coil.
Next, insert the white slider from the bottom into the housing (there is only one way that works smoothly), so it looks out of the top. The O-ring and coil should be at the outside. Finally take the metal stem and push it into the white slider. The orientation is not important. With a plastic plate I pressed on top of it. There are actually two distinct clicking sounds that tell you that it is firmly inserted. You will see that this needs much less power to do.
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Put the assembled switches into a box and make sure they don’t get exposed to dirt or dust.

Replacing the foam
Replacing the foam is one of the most important tasks that you need to do. Especially, if the keys are wobbling around. I also found out that the sound is very much dependent on a proper fitting of the switches.

First of all, you need a foam that is cut to a size of 435mm by 100mm (2mm thickness). In my case this was simple, as I already had a 100mm wide band that I only had to cut at 435mm. I used a Guillotine cutter for this to get a very straight cut.

Next, I placed the foam underneath the switch plate so that the side of the foam was looking towards me. You need to align the foam perfectly at this point and I used glue strips to hold it in place.
Next, I turned the switch plate around and started to mark every hole with a white marker on the foam:
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Once every hole is marked, the switch plate (template) can be put away and we can concentrate on the foam.

Use the 15mm Steel Hole Punch, place it on top of each marked circle and punch out the hole. In my case, I only had to put some slight pressure on it and wiggle it a bit to punch the holes into the foam:
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Once all holes are punched, I removed the adhesive protection and glued the foam to the switch plate like shown below.
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Attach back the plastic gaskets
I used double-sided adhesive strips to glue them back on. First, I placed the double-sided strips on the edges like shown below:
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I removed the adhesive protection and placed the gaskets so they line up with the holes (at this time I also added back the plastic side panels):
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Assembly of Switches into Switch Plate

Place the switch plate on two larger books in a way that the switch heads can stick out of the holes:
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Stick the Switches through the holes in the switch plate. Make sure the orientation is correct and the blind switch for the Space Bar is on the correct spot:
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Finally, screw the PCB back onto the underside of the keyboard in its housing in the correct orientation. You will see that the switches are pressed much harder against the switch plate and won’t wobble as much.

The re-assembling of the keyboard should be straight forward at this point. Add the keycaps back and you might want to give the case itself a nice paint job as well.
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13 Sep 2018, 00:05

Excellent write up! This will definitely come in handy when I restore my 3278.

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13 Sep 2018, 00:51

Great job making this guide. I hope it shows potential buyers how much work and time goes into a proper restoration.

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13 Sep 2018, 16:12

tron wrote: Great job making this guide. I hope it shows potential buyers how much work and time goes into a proper restoration.
Definitely. For those who want to properly restore a Beam Spring board, it will require more time and effort than, let's say, a Model F. But ... for me it was a great pleasure to get it cleaned and the parts replaced that had to be replaced. The end result is a wonderful keyboard, I can even value more now.
After all, I know the board in all his glory now.

I wish there would be still a company out there doing the double-shot keycaps in the original quality. Some of keys would just be great if they would be properly labeled (e.g. PgUp, PgDn, Home, End, etc). I know, many just want to preserve the original printing, but I use it as my daily driver.

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16 Sep 2018, 13:11

Quick update. You might be interested in the typing sound before and after the restoration.

Here's the typing test before any restoration (only the case was painted):
Here's the typing test after the complete restoration (no solenoid):


19 Oct 2018, 03:51

Hello, dark, is there any special point about the thickness and width of the 3M double-sided tape when preparing the stuff?

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19 Oct 2018, 23:52

SilenceGoo wrote: Hello, dark, is there any special point about the thickness and width of the 3M double-sided tape when preparing the stuff?
In my case one layer of standard double-sided tape did work perfectly. In case you run into issues, you can also use two layers of it.

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20 Oct 2018, 12:45

So fixing the foam fixes the rattling issue right?

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21 Oct 2018, 19:36

Wingklip wrote: So fixing the foam fixes the rattling issue right?
You can test this out. If you remove the keycap and look at the switch below. In case you can wiggle on the metal stem and see the plastic housing moving around - it is the foam that has dis-integrated. I had this and after replacing the foam, the keyboard was super crisp and the wiggle was minimal.

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21 Oct 2018, 21:05

Wingklip wrote: So fixing the foam fixes the rattling issue right?
The switches wobble a bit due to thier design but replacing the foam will remove the sound of the module housings rattling around in the switch plate. I shot a side by side video to show the difference. They feel/sound much tighter and more precise with new foam.

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