HP41 IR Printer Module

[Diego Diaz]

Hi,

According to your description you more likely have a bad contact on the BAT line of the odd numbered ports.

Due to internal Flex-PCB layout, the lines for the even/odd interfaces are separated and connected thru the Keyboard PCB. So failures on one "side" (odd) may not affect the other (even).

Most modules don't use the BAT line, that's why you can use other modules on ports 1 & 3 without problems, but IR printer module feeds the IR diode from this line.

Hope this helps.

Best from Caribbean.

Diego.