posted on May, 22 2013 @ 06:02 PM
Okay, just warning folks in advance; this is a conspiracy which will likely only be of interest to techno geeks and electronics but may be of interest
to others as well
As I've noted previously, I work in the electronics field with some pretty advanced systems. Virtually all of these systems require UPS power backup
for power stabilization and battery back up. Consequently, we have literally hundreds if not thousands of UPS's ranging in size from 7-8kVA all the
way to units in the mVA category. Because many of these systems are mission critical the UPS's are monitored via network monitoring.
Recently we've been experiencing a number of failures of network interface (NIC) cards in one specific variation of Eaton UPS's we use. The counts
of failures suggests an endemic problem or manufacturing defect. Eaton, the manufacturer, of course, denies such a defect exists as this card is used
in a wide range of their products. Just to give you an idea of the scale of the problem, we have roughly 50 of these specific UPS units and as of
right now we have had over 35 NIC failures (just under a 75% failure rate).
When the UPS's were under warranty the manufacturer would replace them free of charge. Now, however, they are no longer under warranty and the
manufacturer wants several hundred dollars each to replace them all while denying they have a latent problem.
So yesterday and today I had my technicians go out and pull all the recent failures from the field, and gather up a couple of known working units and
we put them all on the bench to see if we could figure out what's going on. We found a couple interesting things:
1. The problem units all almost exclusively have a part number ending in a "rev. 2". Our known working units actually have the same part number,
but it ends in a "rev. 10", "rev. 17" and "rev. 19". Now the simple fact that the manufacturer of the boards has found a need to revise the
design of a simple NIC nineteen times suggests a problem! It's actually almost stunning that a manufacturer would revise such a simple part so many
times, and suggests something more is going on here.
2. We also noticed that all of the cards which have failed have longer pins at the DIP switch protruding from the bottom of the circuit board.
Immediately under the DIP switch is a grounding bracket which grounds the board ground to the case of the unit. The pins appear almost long enough to
touch the grounding bracket. On all the working units the pins are trimmed off flush with the bottom of the solder point.
The board in question has an Eaton part number of 116750221-001 (rev. 'x') on the board itself. In discussions with the manufacturer they claim
there is no difference between the boards, but if you look at them you can see the different revisions are considerably different in many respects.
The components on some are even different. Eaton claims they can't tell what revision they send out if you order the part (and even allege that the
rev number is meaningless). Yet, we've got a whole bench full of bad "rev. 2" boards, and they claim revision 2 doesn't even exist!
We've determined that this particular product is used in a large cross section of their products from low to high end models. That it is used in
some of their more expensive UPS units might be why they don't want to acknowledge the problem, but yet they cannot assure us they will ship a
replacement that isn't "rev. 2" because, again, the rev number doesn't exist. Frustrating...most definitely, but we will eventually get to the
bottom of it.
Because this is kind of a unique problem, I thought it might be interesting to see what some of the bright folks here on ATS thought.
Personally, I think they're ducking a larger problem. What do you think?