There are all kinds of things going on around here, and the shack has
become quite messy. Too many things to do and not enough time to do them.

We'll hit a number of topics in this column, and try and eliminate all
these scraps of paper with notes on them telling me not to forget
something.

BATTERIES

    With the fall time change I hope you remembered to change, or at
least check, the batteries in your clocks, smoke detectors, carbon
monoxide detectors, flashlights and computer backup UPS's. Batteries are
often forgotten until you need the product, then find out they are dead.
Some detectors will beep or flash when the battery gets low - but what if
you are away when that happens, and you come back a few days or a week
later and they are dead ? You might never know. I just replaced batteries
in a clock radio, a stand alone alarm clock, two flashlights, both smoke
detectors and one UPS.  The carbon monoxide detector plugs into the wall.
I unplug it, wait about 5 minutes, then plug it back in, letting it go
through its self test as a check. If it doesn't boot up properly, try it
in another socket. If it still fails, replace it. The one at my mom's
house had failed, and no one had noticed.

   In one of the flashlights the on/off switch is broken, so it stays on
all the time. I salvaged it by turning one of the two batteries around.
So the light is normally off. If I need it, I just unscrew the cap and
turn the top battery around. This trick also comes in handy if you have a
light with a switch that moves too easily, and gets knocked around - like
in the trunk of a car. Just put a small label on it to note what to do to
get the lamp to light. For most of these projects I use common alkaline
cells that I buy at the discount store. They last anywhere from six
months to a year or more.

COMPUTER UPS's

   I have three computer style UPS's that I use. One powers the computer,
one the TV and VCR, and one the VHF ham rig.  Two units I use have the
same style 12 Volt  7 Amp hour battery. One unit has a 12V 10 AH battery, but a 12V 7 AH will fit.  I test these batteries with a car head light.
If they light up brightly,  they have life left in them. When I replace a
larger battery like these, I always write the date on them with an ink
marker. That way if I see the battery is four or five years old I can
make plans to replace it.

   Some companies are now making specific battery packs for their UPS's.
Like printer makers who make money by selling a low cost printer and high
priced ink, some of the UPS's have battery packs that cost more than the
UPS. Some friends have brought me UPS's that only need a new battery -
but they can't get it out !   Due to surges on the line, excess discharge, overcharging, etc. I have seen batteries swell so much that you cannot get them out without disassembling the whole unit. Many of these units will not work without a battery connected. I keep a used battery around to test these units. I remove the old pack, then see if the UPS will fire up with the test battery. If it won't it's scrap, and I recycle the empty unit at the next  computer "roundup" run in the spring or fall by the local city. The spent sealed lead acid (SLA) batteries are taken to the local scrap yard, and recycled.

REPAIRS 101

   I might as well have titled this section Electrolytic capacitors.
These caps are used in virtually every power supply known to man. And
they fail. Earlier I mentioned a clock radio and an alarm clock that I
replaced the batteries in. That's after I fixed them. I decided to save
some time, and money by fixing them at the same time. The clock had
intermittent problems, and the radio hummed badly, and didn't know the
tune. I had suspicions about both of them.

   The alarm clock had only one screw holding it together. I removed the
battery and the screw, and gently pried it open.  The reason for doing
this was that the button for the snooze feature had become loose, and
required rocking the switch back and forth. Soon after I found that the
clock was resetting itself, like a power failure had taken place, but the
battery was new. Inspection of the opened unit found two things. The thin
plastic tape holding the snooze and other switches had dried out and one
end had come loose, nearest the snooze button. The buttons are small
metal disks that make contact with the board when the plastic key above
them is pressed. This problem was solved with a new piece of common thin
plastic tape, like that used to seal envelopes or mend paper in a scrap
book.

   The second problem with the clock was a 220 uF 16 volt electrolytic
that showed evidence of a white substance leaking from around its seal. I
had a newer 470 uF 25 volt capacitor that was about the same physical
size, and after noting which end of the cap was negative, unsoldered the
old one and installed the new one. I also noticed a few ugly looking
solder joints on other parts of the PC board, and reheated them, adding a
touch more solder. Replacing the case was easy, and the clock was plugged
in, the time reset, and the new battery installed. I unplugged the unit
and plugged it in after a few minutes. It kept perfect time. The alarm
was tested and it too worked. The repair was complete, and the trusty old
clock was reinstalled right next to my bed.

   The clock radio was a bit more of a challenge. It had five screws
holding the case in place, one of them hidden by the battery compartment.
The knobs on the side also had to be removed. The case was gently lifted
off, so the dial cord and assembly would not be damaged. They are a real
pain to try and put back together. After the case was off I followed the
power cord to a PC board that had the display, a small transformer, four
diodes and two capacitors. The larger capacitor was bulging near the PC
board, and when I moved it the leg broke off. No problem. I once again
noted the polarity marking on the unit, then unsoldered it. It was a
1,000  uF 25 V electrolytic. I replaced it with a similar unit rated at
2,200 uF 35 V, and only slightly larger. The fit was near perfect. I then
spied a smaller electrolytic cap on the same board, and decided to change
it too, for good measure. The clock radio was reassembled, a new battery
installed, and similarly tested. The clock display was brighter and the
radio no longer hummed. I could listen to the basketball games at night
again, while laying in bed reading. The radio was installed on the other
side of the bed, and tuned to the voice of Joe Tait describing the Cavs games.

Wham! With the right hand ( and tools, and knowledge ) ...

Jim WD8PFK