The manual identifies five critical zones on the front panel:
If your ZYX-J30 stops working, consult this table derived from the official : zyx-j30 manual
That is normal magnetostriction in the internal transformer. If the hum is excessive, ensure the mounting screws are tight and the unit is not on a hollow surface. The manual identifies five critical zones on the
: This usually indicates the clamps are not properly connected or the battery voltage is too low (below 2V) for the charger to detect. zyx-j30 manual