I'm after some help and advice regarding an RS232 problem.

Machine is a vertical milling machine Shizuoka B-3V with Fanuc 6M control.

RS232 has been working fine with no issues for years using the same hardware/cables/pc

The issue is the machine control is able to receive programs from the desktop PC but is unable to punch to the desktop PC

Machine motherboard is A16B-1000-0030/04C
ROM board is A16-B-1200-0150/01A
Graph Int./Punch board is A16B-1200-0310/02A
BMU board is A87L-0001-0084/05B

From reading the forum it looks like there may be a problem with the RS232 line receiving chip SN75189. Does this sound about right? Is this chip located on the A16B-1000-0030/04C motherboard or the A16B-1200-0310/02A Graph Int./Punch board? Assuming this chip is the issue I'd look to send the offending board away to get a new chip fitted.

Before I pull any boards from the machine I'd like some advice as to any procedures I should carry out first. Would I loss any programs/parameter settings by pulling the boards as I'm unable to punch out any of these at the moment. Once the RS232 receiving chip has been fitted will the board need anything else doing to it before fitting back into the machine?

Any clarification needed please ask.

Looking forward to receiving some help/advice so thanks in advance.