Honey I Shrunk the Keyboard

This Instructable is to modify a 101/104 keys keyboard into a compact keyboard. The benefits of compact keyboard that it can fit nicely on your desk where you do not have room for large keyboard and it can be packed nicely into your traveling briefcase.

I investigated several compact keyboards and found many, especially the inexpensive one, to be quite uncomfortable to type on. I found an old Memorex Telex keyboard (P/N 114769-001) in my closet that I really like. It is a 101-key, clicky, old style DIN keyboard, which my current PC is not supported. Since I hardly use the keypad on my keyboard, my thought is to eliminate the keypad, hence reduces the wide by 3.5 inches. A good shrinking keyboard candidate must have the following characteristics:

- Key switches solder on the printed circuit board, not Mylar films
- Keyboard processor is not in the area of the keypad

Warning: The Instructable and I are not responsible in the events of the destruction of your keyboard, destruction of your computer, unemployment, divorced, political unrest, earth quake, or injury causes by this instruction.

You will need the following tools:

- A good and trusty hacksaw with a brand new blade

- Soldering iron, solders, flux paste, de-soldering tool or solder wick, and some wires

- Hot glue gun, two sided tape

- Multimeter

- General electrical and soldering knowledge, fair amounts of elbow grease
Optional item is a DIN to PS2 adapter or PS2 to USB adapter and extra USB cable.

Open up your keyboard and remove keyboard printed circuit board out of the plastic case by removing all screws from left, right, topside and beneath the skid pad.

Take a photo of the keyboard, so later you can use it as a reference when we put it back together.

Remove all keyboard keys from numeric keypad, all arrow keys, group of six function keys, and print screen, scroll lock, pause keys. You can also remove as many keys as possible from the keyboard. This is also a good time to put all the plastic parts into the dish washer to sanitize them. I would not use the high heat to dry them, parts might be melted.

 

This is where you will need the elbow grease.

Cut off the excess parts. For the Memorex keyboard, I draw a line on the back of printed circuit board where numeric keyboard group begins. Do not cut off the aluminum backing yet.

Desolder and remove all numeric keypad switches

Grease your elbows with prescribed elbow grease.

Cut off the I/O (input and output) /indicator printed circuit board off from the keypad.
Cut off the metal housing.

Cut off the top numeric keypad plastic case along dotted lines (see below). Attach PART A and PART B using hot glue along the inside. Do not over glue, since it may interfere with the main keyboard printed circuit board.

Cut the bottom plastic casing and glue to match the top plastic lid.

Reassemble the keyboard with the top plastic piece; ensure that the keys along the right edge travel nicely. You many need to do some adjustments on the keyboard assembly, so that the keyboard is flush with the new top plastic piece.

Reattach the I/O indicator printed circuit board. You will need some small wires. I use a floppy or IDE ribbon cable from an unused computer or any small gage wires. Position the IO board on the right hand side, so that it does not interfere when the bottom cover is closed. At this time you may need to extend the LED indicators. I only extend the “Caps Lock” LED indicator, since the “Num Lock” will be useless and I do not know the purpose of “Scroll Lock” LED, so I left these two alone. Once you are finished with all wiring points, use the two sided tape to affix the I/O circuit board. Glue gun will help wires from moving around.

Complete the rests of broken circuits. The up, down, left and right keys are still needed to be wired, see the photos.

Take a break. You are working too hard. Here what you should do after you had a couple cans (kegs) of beer...

You can stop here if your computer uses the PS2 connector. Place the original keyboard cable into J1 connector on the I/O circuit board. You can use DIN to Ps2 adapter, if your computer uses a PS2 connector. Before you plug in the connector into your computer keyboard jack, I recommend measuring between PIN 5 and ground to ensure that there is no short circuit, photo for a pin diagram. Repair as needed.

And for the diehard fans...

For the rest of us, who need the USB connection. Please continue. You can purchase the Ps2 to USB module from Ebay. I got one for around $1.65 ( with shipping and handling charges).

Open up the adapter and remove the circuit board from the adapter using a flat blade screw driver or a sharp blade.

Desolder the USB port, Ps2 mouse port, and Ps2 keyboard wires from the module. Please note the wiring colors, especially RED (+5V), BLACK (ground), Green (DATA+), and White (DATA -) and the PS2 keyboard connector location.

Attach the PS2 to USB module onto the I/O printed circuit board. Solder pin 5 (+ 5 V ) to module + 5 V (Red wire), Ground wire to USB module (Black wire),  pin 1 clock to USB DATA – (White wire), and finally pin 2 DATA to USB DATA + to the PS2 solder points.

You may  need to go back and inspect the I/O indicator pinouts identifications from previous step.

Cut the USB cable, besure it is long enough to reach your computer. Solder RED wire to + 5V, Black wire to ground pin, White to DATA – and Green to Data +.

I painted the keyboard black so it matches my computer. Reassemble the keyboard and enjoy your new compact keyboard.