Vytec Transmitter Question

I just changed the batteries in 2 Vytec computers and 2 transmitters and am now seeing a slight difference in operation.

In 300 dives on both of these computers, after a dive, with pressure turned off, the computer displays SETC.

After changing the batteries in both computers and both transmitters, after turning tank pressure off and removing reg from tank, the computer display alters between SETC and Code ----
In some cases, it even finds a code, but never displays air (as the reg is not connected). As soon as the tank is turned on it seems to find a code and display air pressure properly. This happens with both computers on either regulator / transmitter.

Has anyone else seen this?

I have had my vytec search for code after shuting off reg. and disconecting
tank. It has also found the transmiter on my buddies rig.

Your transmitter's shut-off logic may have to be reset, the wrist unit only receives and displays what the transmitter sends. These transmitters are supposed to go to power-save mode if the pressure reading doesn't change for five minutes and the wrist unit will show "FAIL" where the pressure display should be.

As for finding the reading on a buddy's transmitter this is actually normal behavior for a Vytec. When a reg is de-pressurized the Vytec automatically goes into SET C mode and tries to "pair" itself to an available signal. So, if another transmitter is still broadcasting a signal and is near enough to be picked up the wrist unit will pick it up thinking that your trying to pair it up for another dive. This is why it is important to "pair" your units before every dive. I strap the wrist unit as close to the transmitter as physically possible prior to pressurising the regulator.

Or you can keep the wrist unit in its time mode until just before you enter the water. Then switch to dive mode, making sure that you have the "SET C" display, get it as close to your pressurized transmitter and inflate your BC. The momentary pressure drop in the first stage reactivates the transmitter from its power-save mode.