Mid January 2008 we discovered that the BC906 has a max speed of about 70 mph, contrary to our specs and what we thought it could do (the BC1200 goes to about 200.
If you have a BC906 click here for more information.

If the display is completely blank, the battery is likely dead.
To change the battery in the display - DO NOT UNDO ANY SCREWS!
The BC1200 TWISTS OFF the backing:

Battery access is right in back of the display. The battery is a CR2032.

Here are some simplified instructions,
... and some more detailed instructions for the BC1200 too,
... and some basic instructions for Vortex Anemometers with BC1200's.

When you change the battery, make sure to put in the correct WS! The M1 and D2 rotors have different WS numbers. Find your item on this web site and click on the blue MANUALS tab to get to that information!

If this display is alive, but there is no wind reading, chances are the wind sensor is not working. Test the display by disconnecting the wind sensor and tapping the bare wires of the display together. This should produce a reading.

Inspeed has offered 2 rotor models - the M1 and the D2.
The M1 (below) is no longer available. The good news is that the D2 replacement will fit all models. Just be careful to CALIBRATE the display to match the rotor! (The WS setting is different for the M1 and the D2)...

Replacement rotors include a shaft, magnet, and circlip.
Here are instructions for all kinds of things, including rotor replacement:
This is the M1:
Cups about 1 inch out, rotates counterclockwise when viewed from the TOP...

...and this the D2
Cups tight to the center, rotates clockwise when viewed from the TOP.

IF YOU ARE REPLACING AN M1 ROTOR WITH A D2:
- be careful to set the WS to 0711 (if you have a BC1200 display)
- note where the WIRE comes into the head of youor existing unit. It is comes in from the BOTTOM, everything is fine. If it comes in from the SIDE, let us know in COMMENTS when ordering (the magnet in the rotor is different).

Replacement rotors come with magnet, shaft, spare circlips, and instructions.