[LW] [LW11] Adjusting magnetic variation on ST50 multi

[LJK]

I have 2 x ST7000 control heads connected to 3 x ST50 Multi and an ST50 NavData (Course Computer Z083, Fluxgate Compass Z130).

The system’s variation is currently set to 2°E. It should be 0°4’W. From the manauls it appears variation should be adjusted via the ST50 Multi. I can see no means to adjust variation via the ST7000.

With the GPS off (lest it interfere) I attempted to adjust to 0°. But here’s the oddity: the unit resets itself to the previous value after a couple of seconds. (I would post an illustrative video but can't seem to!)

I have tried hurriedly "saving" the new value (pressing depth and log) before the value resets but the new value does not persist.

I have tried disconnecting the two other Multis lest they are interfering. But the unit still resets itself to 2°E. And I have tried performing the adjustment on the other units, but they do the same.

What could be going on?!

with thanks,