DN,

Wait a minute . . .
- - - Don't Plug-in that Soldering Iron Yet !

Since the Panasonic RF-B300 has a "Band Selector" Switch with
mechanical contacts. I would first suggest that you get some good
switch/tuner contact cleaner/lubricant and try cleaning 'contacts' of
the "Band Selector" Switch first. Most of the time mechanical
failures will occur before any electrical failure; but both appear to
be electrical failures. Most of the time individual band reception
problems in multi-band radios are related to the mechanical band
selector switching hardware.


wmcis ~ RHF
..
..
= = = "justtis"
= = = wrote in message ...
Most likely still a cold solder joint. I had a Yacht Boy 400 with a
similar problem..."new" from the factory.
Carefully go over any of the soldering points that you think may belong to
the am section. Also examine antenna leads. Flexing the board with a
pointed object such as a pencil or very small jewellers screwdriver (being
careful not to short anything out), usually will uncover the faulty
joint(99% of the time). Look for any discoloured joints. The next area
to look at would be one of the electrolytic capacitors, and not necessarily
near the am section. Barring any of these, it's most likely a thermal
problem, either with one of the semi-conductors or one of the passive
devices(resistor, cap(pf). Freeze mist routes these out quickly. Hope this
has been of some help.
"Dave N" wrote in message
...
I'm wondering if anyone can help me track down a problem with a SW radio
I just bought at a garage sale? It's a Panasonic RF-B300 (portable),
and when I tested it at the garage sale all bands worked fine. But when
I brought it home the MW band would just barely pick up my local station
and nothing else (HF and FM still worked fine). I took the back off to
check for loose wires on the ferrite antenna, but everything looked OK.
In fact, everything inside looked really solidly built on this radio.
I put it back together, and when I turned it on the MW band was
working loud and clear, picking up stations from all over. I turned it
off, but half an hour later the MW was dead again (except for our local
station). I hadn't moved it or bumped it in the time between when it
was working and when it wasn't.

Does anyone have any ideas of what could be wrong? Like I said, the HF
and FM bands work fine, and the MW band can barely pick up my local
station (but nothing else). Here's a link to some info on this receiver:

http://www.dxing.com/rx/rfb300.htm

Thanks,
Dave.