L297 L298 problem

Hi to all, I’ve build the board with L297 + L298, but I’ve a problem…

At the power on, with enable H, full step mode, and so on, I see the reset state of the L297 with the multimeter, that is output pins are: A = 0V B = 4.4V C = 0V D = 4.4V (0101). This is ok without the stepper connected at the L298. When I connect the stepper, the L927 output pins are: A = 3.4V B = 4.4V C = 0V D = 4.4V (?101). Output A is abnormal, and vary from 3.0V to 4.2V if I turn the trimmer in the vref pin for current control…

Someone can help me? why this? L298 may be damaged?

Thanks