M-Audio Hammer 88 Pro, Service Manual, Page: 32 / 44

1. Cannot turn on the power
1) Problem with the 5V USB power:
a) Cannot turn on the instrument when using USB power. Check if the computer is turned on. Check if
the USB port on computer is working properly.
b) Check if the USB cable is damaged. Try with another USB cable.
c) Check if the PIN1 on USB jack has 5V voltage. Check if the USB jack is properly soldered. If it is
damaged, replace it.
d) Check if the related components of the USB jack are properly soldered.
e) Check both ends of FB2, the grounding should have 5V voltage. If not, then check if FB2 is properly
soldered. If the FB2 is damaged, replace it.
f) Check if the toggle switch is damaged.
g) Check if the voltage on both ends of D8 and D9 is normal, if only one end has it, then D8 and D9
have virtual welding or damage, and the damage will be replaced.
2) Problem with the 9V power adapter:
a) Check if PIN1 of DJ1 detects 9V, Check if DJ1, L2, FB12, FB13, D11 and D2 are welded correctly or
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