I have a Studer A810. Using an MLR Reproducer calibration tapes for 3.75", 7.5" and 15" I performed the level setup, azimuth and EQ. The 7.5" and 15" EQs are fine, but when I attempt to EQ the 3.75" speed the high-end drops almost 8db. I've tried to adjust, but the HF adj is at max. I've looked at it with two different tapes, so I know the tapes are good. The adjustments are through the MPU with 256 steps, so I don't believe there is a way to change the resistance. I'm not sure why the higher speeds are OK. I've tried setting azimuth using both an oscilloscope and an RTW TM3 Primus meter and both are consistent. Other than relapping the heads are there any suggestions how to get the 3.75" EQ in spec? Everything else with the deck is good. Any suggestions would be appreciates.