Hitachi NV 50AG2, Technical Data And Service Manual

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Inject air to check whether or
not the driver blade is left
lowered.
Nails are not completely fed
in the injection port.
Nails not approved by
Hitachi are used.
Replace parts. The spring of the head
valve is abnormal (fatigued
and/or damaged). Inject air to check whether or
not the driver blade is left
lowered.
Fault
Cause
(The mark * refers to main causes.)
Inspection method Remedy
(1)
Nails fail to
eject.
(Continued)
< Control valve section >
Plunger (A), valve piston
(B), valve bushing (A) and
valve bushing (B) are
abnormal (seized and/or
damaged).
Disassemble the control valve
and check the O-rings.
Apply grease or replace it.
Refer to Item 1. Refer to Item 1.
Check whether or not the
driver blade head is
abnormally worn. Replace it.
(2)
Nails are
driven bent.
Replace abnormal parts.
O-rings are worn.
When driving a short nail,
the adjuster set for
insufficient depth. Check whether or not the
adjuster is set for insufficient
depth. Use the nailer with the
adjuster set to greater depth.
(Decrease the pressure.)
* The driver blade is worn.
The wood being nailed is
very hard. Check whether or not the nail
is bent, even when it is driven
into soft wood. The nailer cannot be used
because the material is
beyond its applicable range.
Disassemble the output
section and check whether or
not the piston ring, the O-ring
and the cylinder are normal. * The piston ring is
abnormal (worn and/or
damaged).
The inner face of the
cylinder is abnormal (worn
and/or rough).
Adjust air pressure in the range
of 4.9 --- 8.3 bar (5 --- 8.5 kgf/cm
2 ,
70 --- 120 psi).
Replace the abnormal parts.
(3)
Nails cannot
be driven
into the
wood
completely:
the heads
cannot be
made flush.
The adjuster is incorrectly
set. Try to drive nails with the
adjuster set to maximum
depth. Adjust the adjuster to the
optimum depth.
Check whether or not the nail
heads are flush with the
surface when driven into soft
wood. The nailer cannot be used
because the material is
beyond its applicable range.
Inject air and check whether
or not the driver blade sticks
out from the nose. Replace it.
Air pressure is low.
The wood being nailed is
excessively hard.
* The driver blade is worn.
Check whether or not the
sliding face is abnormal and
oil has depleted. The sliding face of the head
valve is abnormal (seized,
damaged, and/or oil has
depleted).
The cylinder packing or
sealing surface (damaged,
scratched sealing surface). Disassemble the cylinder
plate section and check for
abnormality. Replace the abnormal parts.
Replace the abnormal parts.
Apply grease.
Inner nail guide surface of
vertical guide is abnormal
(worn, damaged).
Defective spring (yielded,
broken). With a finger, open vertical
guide and check the
operation.
Check if vertical guide and
spring are normal. Replace defective parts.