Little battery maintainers

[urq]

... I tend to use the philosophy ... I'm not going to break it worse by
trying to fix it ...

But in this case I'd be skeptical that you'll be able to fix it.  BMW gave
me a Schumacher battery tender with my '92 k1.  It did develop repairable
opens over the years, but eventually an open developed inside the
transformer, which made repair impractical.  Most battery chargers are
little more than a transformer and diodes, but battery maintainers have
electronics which are intended to prevent damage to the battery.  I would
expect this to be a weak point as well, and also difficult to repair.  

Steve Buchholz

-----Original Message-----

What usually fails inside one of the little battery charger/maintainers?

I have a couple of three-year-old Sears 2 Amp (12 volt)/4 amp (6 volt) 
DieHards that say they feature float-mode monitoring.  One still works 
fine--raised an old battery's measured output from 11.8 to a sustained 
13 volts--the other's front lights light up but it doesn't do diddly 
when connected to a battery for multiple days.

So what could be wrong inside?  Easy fix for a fumbling old solderer or 
just trash it?
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