The Odd CIA handles the keyboard, parallel port and part of the floppy ready.

If you have a fault between the CIA and the 68k communication, then the Kickstart ROM will hang at white screen.

Start by checking the CIA is out of reset.

Measure the !RESET pin and it should be 5V.

If not check the U37 7432 OR Gate that the trace connects to pin 11 output (which feeds also into pin 9 input).

The input pin 12 is from the Angus/68k/Paula reset pine so the CIA should come out of reset at the same time as the rest of the system if the OR Gate is working.

Confirm you have good continuity between all of the 68k pins.

They include the data pins D0-A7, the address pins A8-A11, the E pin and the !WRITE pin.

The !WRITE pin should toggle during boot. Slower at first then almost constant once loaded into Kickstart.

The E pin should be a 709.4kHz constantly pulse.

All Data and Address pins should toggle constantly. The address pins toggle slower while initially loading then almost constant once booted.

The !INT2 pin should go high for a second or so, then start pulsing in short pulses low at random intervals.

Once booted it goes to a 10.82Hz regular pulse.

This pin sits idle high for about a second while the BIOS is read, then it starts pulsing randomly during boot.

Once loaded into Kickstart it is a constant regular pulse.

The Tick pin is the VSYNC so will show the frequency pulse your monitor output is running at, in this case 49.92Hz.

The Gary Overlay signal goes high while the BIOS is loading, and then pulls low afterwards.

The Keyboard Clock and Data pins sit high at 5V DC while booting, if no keyboard is connected.

The keyboard !LED pin is high for a second while the BIOS loads, then low afterwards.

So long as the Joystick buttons are not pressed the FIRE0 and FIRE1 remain at 5V DC.

All PPD data pins, and the F (PP Acknowledge) pin, and !PC (Strobe) pin all sit at 5V DC with nothing connected.