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Solution/Action:
This problem is often caused when one or more of
the four ribbon shield guide brackets is mispositioned leaving
little or no clearance between it and the coil board assembly.
When contact is made between the soldered coil terminal points
on the underside of the coil board and the ribbon shield guide,
a short occurs. This leads to the possibility of destroyed
transistors on the hammer driver board which produces the
“hammer voltage fault”.
A visual inspection will determine whether there
is a clearance problem between the terminals on the coil board
and the ribbon shield guide. If about 0.010” or more (definite
clearance by eye) cannot be verified, replace the hammer driver
board (the transistor is blown anyhow - PN 082578). At the same
time, ohm out the coil board to check for coil damage so that it
can be replaced also, if it is damaged (PN 083685).
Prior to reassembly, wrap Kapton tape (or a
similar durable insulation type tape) around the ribbon shield
guide bracket to prevent metal-to-metal contact.
Obviously, this is most easily accomplished with
the hammer driver board and the coil board removed. Watch as you
mount the hammer driver board and bias it (move it against the
screws) so that there is maximum clearance. |
