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Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:04
by consideringquiet
Hello.
Recently I came across a
P70 keyboard which I hoped
to easily convert
to PS/2. However, it turns out
to not be as easy as is reported by every single post on here.
I spliced up a Fellowes Keypad, which had wires of orange, red, brown, and black color. My friend tested for continuity, and two led
to pins reported as "n/c" or not connected. We assumed that the pins were for split
PS/2, and coded the orange as data and the brown as clock.
Orange matched up
to pin 2 on the
ps/2 pinout. Brown matched up
to pin 6.
We used jumpers
to match as follows:
Fellowes Keypad -
P70
Orange ("Data") - Red
Brown ("Clock") - Green
Red ("VCC") - Yellow
Black *"GND") - Black
However nothing happened when we plugged it in. No light or any response from the keyboard whatsoever.
Any help would be appreciated.
Here is the photo I used
to attempt the first wiring:
- 8573_KB_conn2..gif (4.07 KiB) Viewed 3538 times
- 150px-MiniDIN-6_Connector_Pinout.svg.png (21.01 KiB) Viewed 3526 times
Re: Adapting P70
Posted: 18 May 2019, 22:12
by snacksthecat
The first thing
to check would be is it getting (enough) power?
Do you have a multimeter?
Open up the keyboard and look for all of the ICs (chips).
Use your multimeter
to measure the voltage by touching the probes
to the pins indicated in the picture.
Each one should measure close
to 5v (probably like 4.6-4.8 in reality).
Note: these aren't always the Vcc and Gnd pins, just very frequently. If you google the number written on each chip, you can usually find the datasheet which will tell you the exact pinout of the chip.
Re: Adapting P70
Posted: 18 May 2019, 22:18
by consideringquiet
snacksthecat wrote: ↑18 May 2019, 22:12
The first thing
to check would be is it getting (enough) power?
Do you have a multimeter?
Open up the keyboard and look for all of the ICs (chips).
Use your multimeter
to measure the voltage by touching the probes
to the pins indicated in the picture.
Each one should measure close
to 5v (probably like 4.6-4.8 in reality).
Note: these aren't always the Vcc and Gnd pins, just very frequently. If you google the number written on each chip, you can usually find the datasheet which will tell you the exact pinout of the chip.
I'm not certain it's possible for me
to disassemble it, just due
to the sheer number of clips the keyboard uses
to stay together. I do not wish
to damage the board further than I already have.
Is there any other way I can attempt
to solve this externally? I fear I may have permanently damaged the board through attempting
to test it.
Re: Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:20
by consideringquiet
Also, I saw a comment online instructing not to join the two shield grounds. Is there any reasoning for this?
Re: Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:21
by snacksthecat
Can you post the ps2 pinout picture you referred to in the OP?
Re: Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:23
by consideringquiet
snacksthecat wrote: ↑18 May 2019, 22:21
Can you post the ps2 pinout picture you referred
to in the OP?
Sure:
- 150px-MiniDIN-6_Connector_Pinout.svg.png (21.01 KiB) Viewed 3529 times
Re: Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:29
by snacksthecat
You confirmed with the continuity tester that each of the colors from the keypad cord correspond with those positions in your ps2 pinout image?
I'll keep thinking but nothing is jumping out at me immediately. Do you have a teensy? Soarer's simple logic analyzer would be a good tool to test with if you do have a teensy or promicro board laying around.
Re: Adapting P70 Keyboard to PS/2
Posted: 18 May 2019, 22:33
by consideringquiet
snacksthecat wrote: ↑18 May 2019, 22:29
You confirmed with the continuity tester that each of the colors from the keypad cord correspond with those positions in your ps2 pinout image?
I'll keep thinking but nothing is jumping out at me immediately. Do you have a teensy? Soarer's simple logic analyzer would be a good tool
to test with if you do have a teensy or promicro board laying around.
I did, however, two cables led
to pins that are supposedly not supposed
to be connected as per the image.
I do have a teensy, but its not really usable right now. Still sitting in my failed NCR 4950 project. I can't seem
to catch a break here.
Re: Adapting P70 Keyboard to PS/2
Posted: 23 May 2019, 02:44
by consideringquiet
Delirious wrote: ↑19 May 2019, 00:35
3F6F53CB-5B09-4DE8-BC3D-03F53FF105D9.jpeg
EBD0B4CC-5D82-4CD2-A447-8C63DFAC682E.jpeg
E98F7EC3-F55B-4DBF-89CC-BBE3F9792A32.jpeg
99C817E0-E1AE-4EF0-9D17-9C149C0E6141.jpeg
I'm sorry, Is there any way of doing the conversion without opening the case?
Re: Adapting P70 Keyboard to PS/2
Posted: 24 May 2019, 02:21
by consideringquiet
Has anyone done this conversion before?
Re: Adapting P70 Keyboard to PS/2
Posted: 27 May 2019, 09:07
by Chyros
I literally just connected the wires from the
PS/2 cable
to those from the
P70's; twisted them together and then joined by soldering. I can't remember the details anymore unfortunately; it's been a while. If you want I can unscrew my converter box and look inside at what I did
.