FMCG/Magnetometer Array Troubleshooting

Here are some tips to troubleshoot common issues with the magnetometer array.

Endless TA-7600 error messages on the laptop

This will often happen if the pump laser diode is disabled, but the program is left open for a long time. To counter this, simply do a Ctrl+Alt+Delete and in the task manager, close the TA-7600 program under Applications.

4.5 Hz "square wave" signal on magnetometer

This probably means the Tristan SQUID was left powered on. That control box is in the setup room on the floor next to the BTi electronics rack. There's a simple on/off switch next to the power cord socket. Make sure to check with one of the SQUID people (Sarah or Bill, most likely) that it's OK to turn it off. Then hit the switch and unplug it for good measure.

High 60 Hz noise

Oh, so, so many things it could be.

1. Make sure that the cases of the two +5 V power supplies (one for the heater fan and the other for the LCD screen) are not touching. I've seen this generate HUGE 60 Hz noise magnetic fields.
2. Make sure the Tristan computer (to the left of the desk), Tristan NI chassis (inside of the shielded room), and chassis fan (controlled with the red and black striped power cable plugged into the white surge protector just behind the laptop) are all turned off. If any one of these is still on, again ask Sarah or Bill if it's OK to turn it off.
3. Check to see which output resistors you're using on the shell coils. I've found that using 1k output resistors on the Y can often generate an unacceptably high 60 Hz noise level. With the room coils nulling out most of the fields, it shouldn't be necessary to use such large resistors on the X and Y shell coils. The Z may have to be higher due to Z-mode field requirements, but as that's not one of the two detection directions, it shouldn't be as important.