I have a Honda in-dash CD (and HVAC) control board and I want to see if I can make its LCD work. After I melted through conformal coating over the Sanyo LC75883 LCD driver chip, I was able to get an electrical connection with my meter so I can test for continuity between the pins (that are too fine for me to solder) to something I can more easily work with. I quickly found that much of the CD player functionality is connected to a small black rectangular connector I noticed earlier. Not just the LCD driver chip’s data communication lines, but also the big central rotary knob and button.

There is a large degree of uncertainty here, because I didn’t find what all of the pins did. I also found two pins that both appear to be ground, and I don’t know if there’s an important distinction between those two pins. This incomplete understanding explains the problems I will encounter later.

Using the numbers on the circuit board silkscreen, the pins are 1 to 24 from right to left. (Silkscreen shows 1 in the upper right, 2 in the lower right, 23 in the upper left, and 24 in the lower left.)

Pin	Preliminary Name	Description
7	Vss (?)	Either 7 or 9 is ground, maybe both?
9	Vss (?)	Either 7 or 9 is ground, maybe both?
14	Vdd	+5V power supply
16	DO	CCB Data Out
17	DI	CCB Data In
18	CL	CCB Data Clock
20	CE	CCB Chip Enable
21	A	Encoder A, connects to ground when knob is at certain positions.
22	B	Encoder B, connects to ground when knob is at certain positions.
24	Button	Connects to ground when “AUDIO PWR” button is pressed

Once these connections were made, I could make further progress. That is, running into an entirely different set of headaches.