_ DEC-O-LOG for H7318

_ DOL, H7318-S001, Power Distribution System, MAY 90

PROBLEM: 1) Failure of the unit to shut down in the presence of
overheating, brown "banding" of charring in bands on the main
transformer, and potential burning of the main transformer.
2) Back-up Battery frequently not delivering power to the 
P4 PCB. The fuse located between the battery and the P4 PCB is
under-rated and is blowing.  Replacement of the fuse is mandatory.
3) Programming errors were found in the firmware on both the M3
Processor PCB (Version 2.52 and earlier) and M4 Main Processor PCB
(Version 2.3 and earlier).

FIELD EFFECTIVITY: All H7318 (PDS PLUS) manufactured prior to May 1989.
Includes variants -Ax, -Hx, and -Lx.

QUICK CHECK: Problem #1:  If a three-sensor switch assembly is
located in the primary windings of the Main Transformer, the FCO
has already been installed in the factory or in the field. Problem #2: 
Examine small fuse located in-line between the batter and P47 on the P4 
Power Supply PCB. If the fuse is 2 amps (3ag), it must be replaced.  If 
the fuse is 4 amps, this upgrade is not necessary.  Problem #3: Examine 
the M4 Main Processor PCB located in the upper left position on the front 
door of the unit. Look for the stamped revision letter next to the vendor 
part number (112748).  The revision letter must be "J" or later.

FCO KIT ORDERING:
EQ-01573-06 Thermal Switch Kit
EQ-01573-02 Battery Fuse Kit
EQ-01573-04 Network/Firmware Kit
FA-04902-01 FCO Document