Differences Between Old & New Versions Of Hvps & Engine Pcb - Brother 1240 Service Manual

APPENDIX
APPENDIX 23. DIFFERENCES BETWEEN OLD & NEW VERSIONS OF HVPS &
ENGINE PCB
The high-voltage power supply PCB and engine PCB have been upgraded since the
production in the middle of September, 1999 in order to improve print quality. In accordance
with the change, the T/R electrode helical spring and plastic chute have been also changed.
This section describes the differences between the old and new versions of those parts so that
the service technician can identify the old or new version at a glance.
High-voltage power supply PCB / Engine PCB
Check the pin number of the connector on one of the high-voltage power supply PCB and
engine PCB, which connects those two PCBs. While the old version has 7 pins, the new
version has 8 pins. The figure below indicates the connector on the Engine PCB.
Old version
T/R electrode helical spring / Chute
The size of the T/R electrode helical spring is different between the old and new versions.
While the spring is assembled onto the big boss on the plastic chute for the old version, it is
assembled onto much smaller boss on the chute for the new version. Note that the assembled
position of the spring is also different.
Old version
New version
7 pins
Engine PCB
Fig. A- 16
New version
T/R electrode
helical spring
Chute
Fig. A- 17
A-34
PR99174
8 pins