"Frank346" wrote in message
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"Radiosrfun" wrote in message
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Anyone here with "in-depth" knowledge of the Bearcat 250 Scanner and
repairs?

The service manual you have is the only one I know of. Scanner
manufacturers never update the manuals until there is a catalog number or
model number change.

During the life of a product there are changes made in production. I have
an Electra schematic (engineering drawing) for the BC300 and it went
through a dozen changes at the time the drawing was made. Finding a
drawing like this for the 250 would be nearly impossible now.

Electra often tack-soldered parts to the back of the boards. Maybe Q206 is
on the back in your 250.

Q206 serves as an amplifier to reduce the current in the Zener and improve
regulation. If the voltage at the emitter of Q204 is much less than 8.4
volts, a good portion of the circuitry in the radio will not operate. You
can try replacing the Q204 regulator with a 9 volt three terminal
regulator feeding into a 1 amp diode. That should give you about 8.4 volts
and has the bonus of overcurrent and thermal protection. The original
design ran Q204 way too hot and it is a common failure point. Adding a
heatsink and drilling a few vent holes helps.

Many of the IC's in the radio are custom and very hard to find if one
needs to be replaced. When I had a 250, I recall it being very sensitive
to disturbances on the AC line, often hanging the scan cycle or corrupting
the programming.

With all the negatives about the 250, I'd look for a more recent model on
Ebay to replace it. Something simple with 50 or 100 channels should be
available cheap and it will perform better than the 250 ever did.


Therein lays "part" of the problem... Q204's voltage is ok at input but
significantly slacks off on output. MY issue at the moment is - the book
"shows" a Q206 - but there is not one there! IF you have the manual - refer
to it - you'll see the 9v zener etc, there. ALL is there but Q206. It is
weird.......
It doesn't appear to have been "placed" there to begin with.

I was shooting for trying to figure that out - then finish troubleshooting.
As for someone's posting of starting with the power supply, that is exactly
what I've been doing til I ran into parts not there - as shown. That is
usually where I start - with ANY issues I have unless directed otherwise by
symptoms.
I was eliminating all the parts as the book lists as suspects. I believe I'm
in a definate problem area with the voltages - but still - where the hell
did Q206 disappear to? IF there is no other info to be had, I'll take a nice
LONG look at it in the morning and see if there is something else I can work
out. I'm 99.9% sure I have a new Q204 to pop in if this one is weak. I just
stopped where I was to try to figure out what the heck was going on.

I've researched most of the info - if not all - available by Parness(sp?) -
that I could find. I'll just take a good close look tomorrow and see what is
what. Was just hanging back to see what replies I might get to help out.

THANK YOU FOLKS for your input.

Lou