ROD END 2M4036 - Caterpillar

REBE8844-00
10Dec2012
D-566
O-607
Before/After
PRODUCT SUPPORT PROGRAM FOR REPLACING THE 3659786/">365-9786 EXPUT BOARD ASSEMBLY, 3659798/">365-9798 DIGIT BOARD ASSEMBLY, AND 3659803/">365-9803 EXTT BOARD ASSEMBLY ON CERTAIN UPSB505 UNINTERRUPTIBLE POWER SUPPLIES
4480 PS43786
This Program must be administered either before or after failure.In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS43786" as the Part Numberand "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and "T" as the SIMS Description code.If administered after failure, use "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.
The information supplied in this service letter may not be valid after the termination date of this program.Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
TERMINATION DATE
31Dec2014
PROBLEM
The existing EXPUT, DIGIT, and EXTT boards can cause fault propagation and possible contingent damage on certain UPSB505 Uninterruptible Power Supplies in a parallel application with other UPSB505 Uninterruptible Power Supplies.
Existing DIGIT failure.
If an IGBT failure occurs in one UPS, the resultant exchange current can be higher than normal limits and can saturate (disturb) the multiplexers on DIGIT in other parallel UPS. This can generate false alarms such as Inverter Lx fuse blown instant?. As a consequence of this, other inverter(s) could stop and load be transferred to AC bypass.
Existing EXPUT failure.
If a unit fails (UPS or SSC), that unit needs to inform other units it will be disconnected. Otherwise, the system will not work properly (downgraded mode).
The reserve of energy on board may not be sufficient to guarantee this communication in case of failure (example, DC bus short-circuit, power supply failure).
Eisting EXTT failure.
If a UPS fails, it will disconnect whereas higher current can occur in the parallel CTs. At this moment, relays on EXTT board, which are in serial with secondary of CTs may be damaged and contacts may be welded. After that, the installation will not work properly since exchange currents will be false.
AFFECTED PRODUCT
Model Identification Number
UPSB505 YTM00100-00124, 126-127
PARTS NEEDED
Qty
Part Number Description
1 3659786 BOARD AS. (EXPT)
1 3659798 BOARD AS. (DIGT)
1 3659803 BOARD AS. (EXTT)
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 23% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
ACTION REQUIRED
This FSB concerns only units in parallel installation and SSC.
Refer to the service manual if/as necessary.
Replace DIGIT & EXPUT & EXTT boards if not at the minimum level requested:
DIGIT NT 07 EJ
EXPUT NT 04 HA
EXTT NT 04 EB
SERVICE CLAIM ALLOWANCES
Product smu/age whichever comes first Caterpillar Dealer Suggested Customer Suggested
Parts % Labor Hrs% Parts % Labor Hrs% Parts % Labor Hrs%
0-20000 hrs,
0-60 mo 100.0% 100.0% 0.0% 0.0% 0.0% 0.0%
This is a 2.0-hour job
PARTS DISPOSITION
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.