[SEL] OT - Broadband Router problem and solution

[Listerdiesel]

This 'might' help anyone else in the same situation, and it has been a
recurrent problem with USRobotics equipment for us.

We had a local network problem on the system at the factory.
Occasionally we would lose the network completely, although the
(cabled) router would show all the right indications etc.

This week two of the indicators were going crazy and the network was
down, so we brought in a spare from home today, and after some
swapping of bits we identified the Chinese-made PSU as only putting
out 2.5V instead of 5V.

Running the router from a 6V battery (through a couple of voltage
dropping diodes) showed that the unit was functioning OK, but the
on-board regulator was getting warm, and we are going to replace one
of the smoothing caps which has a bulging can end. We suspect the old
PSU went high on volts which caused the regulator to shut down on
overtemperature.

Over the years we have had three USR PSU's go down, so we are going to
fit a larger unit as replacement, with 2.5A capability instead of the
2A of the USR unit.

These do run 24/7 so the hours online are quite high, but the PSU's
don't seem to have any reserves or protection against downstream
failures, so we may change all of them. The replacement unit has a
different type of supply, so it may be that USR themselves have seen
the problem and changed the manufacturer/design or both.

We picked up some universal input (110-240) 5V 2.4A PSU's with output
cable and plug, IEC input, for $14 at HSC in San Jose last week, so
one of those has an immediate use :-))

Peter
-- 
Peter A Forbes
Email: listerdiesel at gmail.com
Web: www.oldengine.org/members/diesel