The Cheap PS/2 Arcade Trackball

Broken trackball? Not working? Curious about the innards?

I bought one of those cheap / inexpensive PS/2 trackballs off eBay for my arcade system.

It goes by a few different titles:

Illuminated 4.5cm Round PS/2 PCB Connector Arcade LED Trackball Mouse + 4 Screws

4.5cm Illuminated Round PS/2 PCB Connector Arcade LED Trackball Mouse + 4 Screws

It has a large "H" printed on it. Newer ones on eBay are labelled with "KM".

An overly aggressive friend hammered the trackball during a game of Golden Tee, cracking a plastic part inside. I had to fix it, but this lead me to do a complete teardown, 3D model of the inner plastic, and sketch of the PCB.

Here is the PCB as well as a schematic. This schematic is NOT perfect. I threw it together haphazardly. The red and green LEDs I didn't map out because I'm lazy. The optical phototransistor is purely a guess.

The hardest part of figuring this out was the phototransistor. I had to find a phototransistor with dual sensors, which isn't very common in my searching. I finally found it with the company Everlight. They go by the name Everlight Electronics Co., Ltd.

They have four versions of this phototransistor. Here is my best guess what the variance between them is...

PT2559B/L2-F - short leads, -25 ~ +85℃

PT2559B/L2/H2-F - same as above, but with longer leads

PT5529B/L2-F - better operating temperature vs the above. Short leads, -40 ~ +85℃

PT5529B/L2/H2-F - same as the above, but with longer leads

I can't say for sure if I'm right. This is just my best guess.

Here is my best guess BoM...

Name Designator Quantity

47pF C1,C2,C3 3

100nF C4 1

10uF C5 1

100nF C6 1

22272041 CN1,CN2 2

1N4148-35 D1,D2,D3 3

PT2559B/L2 LED1,LED2 2

1.2k R1 1

680k R2,R3,R4 3

47 ohm R5,R6,R7 3

51k R8 1

EM84510EP U1 1

CD4049UBE U2 1

IR908-7C-F U3,U4 2

Right now I'm trying to model the plastic in Fusion 360. I'm an absolute amateur with Fusion 360, so it has been slow and painful.

I've already gone through multiple revisions. I'm almost there. Original piece on the left. Final model will be two parts. Bottom part has the ring column that drops below the PCB plus supports for sitting on the PCB. Top portion has the bearings and wheels.

I figure I have at least 2 or more revisions to do before getting this right.