On Mon, 09 Jul 2012 12:48:08 -0500, Peabody
wrote:
This is an APC Model BE550G UPS.
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=BE550G&tab=features
Not the best UPS on the planet, but cheap at about $70.
It's just a few months old,
If "a few months" means 2 months, it should still be under the 3 year
warranty from APC.
http://www.apc.com/site/support/US/en/product/BE550G/
but
has developed an intermittent problem that I'd like to fix if I
can. I know if I send it back to APC it will just happen to be
working then, and I will have accomplished nothing.
How do you know? I sent a UPS back because the stupid light was
burned out. (Long story, don't ask). I got a refurbished UPS back in
the mail in 3 days. Instead of guessing, maybe reading the warranty
might help?
http://www.apc.com/site/support/index.cfm/warranty-services/in-warranty-services/
How Does Standard In-Warranty Service Work
Defective products may be returned to APC by the customer for
replacement or repair during the standard warranty period.
Defective products will be replaced or repaired and returned
to the customer. Customers who must have original units back
rather than replacement units due to assigned asset tags
and set depreciation schedules must declare such a need at
first contact with APC. It will be APC's standard practice
to issue factory reconditioned replacement units in exchange
for original units. The warranty on reconditioned units
delivered for in-warranty service is 90 days or the remainder
of the original warranty period, whichever is longer. Repaired
units carry the balance of their original warranty period.
So it is written, so it must be. (Charlton Heston in The 10
Commandments)
The problem is that sometimes when the UPS switches into backup
mode, no power gets to the plugged-in devices.
Been there. There's a transfer relay inside. The contacts are not
making good contact or the contacts are pitted from trying to switch a
potential overload such as a laser printer.
I called support, and they had me reset the sensitivity of the UPS,
and of course it started working then. But I strongly suspect this
has nothing to do with sensitivity - after all, it's hard not to
notice the mains dropping out completely.
Well, at least you tried calling support. Support runs on the
assumption that nothing is wrong and that you must have done something
strange to cause the failures. That's not unreasonable as 80% of the
devices returned under warranty have nothing wrong with them.
Logically, what this seems like to me is that everything is working
ok, but the relay which switches over to supplying backup power to
the devices has bad contacts that don't always make contact.
Yep, you got it.
I can
hear the relay click when it goes into backup, and again when it
reverts to mains, and I can hear that whether the backup power gets
through or not.
Well, if you're ambitious, open the box and look inside. If the relay
is an open frame type (fairly common), you should be able to inspect
the contacts. If the relay has a cover, it can usually be removed to
reveal the contacts. My guess(tm) is that you'll find pitted contacts
or a mangled relay armature.
Well, I just wondered if anyone here has any experience with this
kind of thing, and might offer some advice on what to try. I have
already opened it up and made sure all the internal cable contacts
are good, even tightened a couple just to be sure, but that didn't
help.
You opened it up and you didn't look at the contacts? Sigh. Unplug
the unit. Turn it off. Disconnect one lead from the battery. Tear
it apart again. Look at the contacts (with a magnifier). Are they
pitted? If so, clean them.
Any advice would be appreciated.
Well, if you want to risk you life, run the UPS with the covers off.
If it goes into backup mode without any output again, push on the
relay armature with an INSULATED wooden or plastic stick and see if
the output magically appears on the load.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#
http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS