Tremolo on high but not low power

I've got a 210HD, that when it's in high power, the tremolo works. In low power, it doesn't.
Is this a "feature"? Any idea for a fix if not?
Thanks!

Try adjusting the trim pot on the main circuit board for the trem. Be careful-if you have a 12ax7 PI tube, there is a bias adjust pot there too. The bias adjust comes out of point B on the board so you can follow that back to find out which one is which. Mike.

If you have an older 210HD, the Hi/Lo power switch changes a tap on the Primary side of the power transformer, lowering ALL the secondary voltages in the amp, including the raw voltages feeding the preamp and trem circuits (potentially).
It is possible that your trem bias pot is set to a point that allows it to work at the high power setting but it falls out at the low power setting.
Check out the tremelo setting procedure in the posted Music Man Factory Service Bulletins and simply balance the setting to be most correct at both power settings of your amp.
Steve