Observe baldheaded objective centered, levels, surface clean no scratches, increase of laser power is invalid, try play normal after new baldheaded, specify on the bald head. After careful measurement of dismantling the old bald head, found the tracking coil resistance up to 92 Ω (metering head row line {3}, {4} terminal, normal about 12 Ω), then remove the dust cover, check the coil wire and support shall be between the solder joint, for the top solder joints virtual welding! With pointed soldering iron to be welded, the laser power potentiometer recovery after back to the original machine, play normal.uWaservice manual download site