Normic 1600 fire service issue

Hi there, does anyone have a print or a write up about the fire recall on Northern 1600?
It is a triplex with dispatcher, car 2 and 3 are working fine. Car #1 is working fine in normal operation but if Phase 1 (key or automatic signals) are triggered, it keeps dropping FSP, IRR... as soon as it lose its leveling UL or DL.
it is only happening under fire recall sequence. Not sure what's happening on the boards when the fire recall is engaged. it happens in both direction.
I would appriciate some documentations or pointers. (I think it is the main car top board)
Thank you.

Do you have the MAP tool?
Verify inputs for fire service if you can through the tool. I do know that without IRR up the car won’t run. It only toggles at the end of a run.
Hopefully someone here does have access to prints. Good luck.

I do have the map tool, the fire recall from what it can see is done through serial communication, the only I/O that I have are buzzer,Phase 2 ON,Off,Hold.
I do loose IRR once it start to take off, Not sure if the tape head is tripping or something else.

When you initiate fire recall, and the unit fails, what’s displayed in the LCD screen? Any info there that might help other than “IRR (or FSP) LOW”?
I wonder if the issue is DZ related as the failure is right at the beginning of motion in either direction.
*Is FSP recall related?