Section 5: Trouble-Shooting and Repair
MicroBlaster MB1005
Comco Inc.
5-10
Issue Date: September 2003
Pinch Delay Adjustment
The abrasive pinch assembly is equipped with a delay valve (flow control) to prevent it
from opening for 10 - 15 seconds after internal pressure is released. This allows the
tank pressure to escape through the vent hose, rather than the nozzle. If the abrasive
pinch opens too quickly when depressurizing, tighten the screw on the flow control.
Refer to Appendix B, Figure 10. If already tight, it will be necessary to replace the flow
control.
Inspecting and Repairing the Modulator
(refer to Figure 5-1)
Proceed as far as necessary according to the problem.
1.
Turn the power OFF and unplug the unit.
2.
Remove the tank lid and dump the powder from the tank.
3
Remove the MicroBlaster cover (4 screws).
4.
Loosen the nut on the modulator hose fitting and detach the hose from
the modulator.
5.
Using a 7/8" open-end wrench, remove the coil retaining nut from the
modulator housing. Slide the coil and 1" washer off the modulator
housing.
Save the washer
.
6.
With a 7/16" open-end wrench across the two flats of the modulator nose,
remove the modulator nose from the stainless steel body.
7.
Examine the polyurethane seat cemented on the modulator nose. It
should be smooth and unmarked except for a faint ring (impression)
matching the ring seat on the core.
8.
Tip the tank and allow the
core to slide out. Note the core’s orientation,
the cross-holes must be nearest the tank.
9.
Examine the edges and ring seat of the core. They must be smooth and
even. If it has any scratches or roughness that can be felt with a
fingernail, replace the entire Modulator Housing Assembly MB1301-2. If
neither the nose seat nor the core is worn, reassemble the modulator
housing assembly and skip to step 13.
Note:
Make sure the core is inserted properly into the housing. The cross-holes
must be nearest the tank.
