How do we test a Sperry Marine VMFT PCIO Board if no PCIO power supply in hand?
Do some study on this pcb and we realise that the PCIO power supply provide +24Vdc, +/-15Vdc to the PCIO board.
The PCIO power supply giving power to PLP plug on PCIO board. This PLP plug then route the +/-15Vdc power to TSY pin1,2,3. Where 24Vdc route to TSK pin1,2. Using a normal PC power supply and isolate the +/-12Vdc to connect to TSY as input. TSY was supposed to be use as interswitch power, for this case it act as a input to power PCIO instead. After power up the PCIO board, we need to connect a USB cable at TSU. This cable can be made easily by using a printer USB cable and cut one end and made into a 5way wires. Then connectthe USB end to any laptop to check the com port 3 to 9 whether appear on the the laptop com port device manager. It it does, then the PCIO is working normally.