"Josey221" wrote in message
...
I've got another update. Now I can't even get AM. I used to get AM, but
now I
hear the same static noise that I hear on the Air/Police High/Weather
band.
There is also another problem with the radio. It works fine on AC, but
when you
try to power it on DC, it's a no go. It takes 4 D batteries. I've cleaned
the
contacts, checked the wiring, and still nothing.

The first thing I'd look for is poor solder connections or a cracked printed
circuit board. Take the radio's back off and gently press on the board on
different places. You can also use the eraser end of a pencil to poke and
tap around. You might get lucky and find that pressing a small area will
make the radio cut in and out. Just re-solder all the connections in that
area. Be careful not to make solder bridges. Otherwise, you might try
re-soldering any joints which don't look perfect, particularly the solder
joints around the bandswitch{es}. Look around for cracks in the board. If
the board is cracked, you need to scrape off the solder mask {that's the
paint on the backside of the board} and bridge the crack with a bit of
solder. If you're fussy, you can solder a short length of wire across a
crack.

If you have any junk boards around, say from a computer or something, you
can practice your soldering on those.

Be careful pulling the circuit board. You'll probably need to remove some
knobs. The knobs are probably glued in. The glue is usually fairly soft,
but it still has quite a grip. Be patient, and try to work them off slowly.
The wires which attach to the board are usually thin and fragile. Make a
diagram to show which wire hooks up where. You may need to unsolder some
wires to get the board out enough to get to the backside.

Be sure your screwdrivers fit the screws. They may be in tight. You might
need to take your radio to the hardware store and check out a couple of
different phillips head screwdrivers. Or they might be Reed & Prince or
Posidriv. They all look pretty much the same, but only one gives a tight
fit.

The dead bands may be working, but may be way out of alignment. This often
happens when "troubleshooters" start turning adjustment screws or squeezing
or ezpanding coils. There may still be some sensitivity at some unknown
frequency. Try tapping on the antenna rod with a piece of wire or a
screwdriver. This should produce some clicking noises from the speaker.
Check it on a working FM-VHF band so you know what to listen for.



This may sound like a lot of trouble for a cheapo radio, but I'd like to
learn
about how these work. I've always been curious about that part of it.
Also,
once you've unsoldered one end of the capacitor, can you test it with a
multimeter, and if so, on what setting. I have an analog Craftsman
multimeter.

Thanks again. :-D

You can test for dead shorted, or almost dead shorted caps with a
multimeter. These caps will show a short or a resistance on the "ohms'
range. A problem limited to some of the bands could be one of the trimmer
caps related to the dead bands, but these are usually reliable. Water can
damage them, so look for water stains.

Most of the radio's capacitors, and all of the electrolytics, are part of
the radio's power supply and the audio amplifier. These should be OK,
because these are used on all the bands.

I'm assuming this radio has a PC board and I don't know how to unsolder one
end of most capacitors on a PC board and check it. Axial lead capacitors
usually need to be removed to be thouroughly checked. A capacitor with a
gross short will read 0 ohms in circuit.

I suggest you check for poor solder connections and cracks first.

Frank Dresser