Re: Bearcat Repairs


"Radiosrfun" <Radiosrfun@xxxxxxxxxxxxxx> wrote in message
news:467f6830$0$8621$ecde5a14@xxxxxxxxxxxxxxxxxxx
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.


.

Relevant Pages

  • QRe: Bearcat Repairs
    ... through a dozen changes at the time the drawing was made. ... volts, a good portion of the circuitry in the radio will not operate. ... regulator feeding into a 1 amp diode. ... I was eliminating all the parts as the book lists as suspects. ...
    (rec.radio.scanner)
  • Re: TECH:Rottendog Data East Power Supply DPS004 + older DMD
    ... put the DMD in another machine and it worked fine. ... The voltage on the output of the LM317 will be 1.5 volts. ... regulator available or it probably would have been the first choice. ...
    (rec.games.pinball)
  • Re: TECH:Rottendog Data East Power Supply DPS004 + older DMD
    ... The datasheets max voltage is 60 volts. ... regulator available or it probably would have been the first choice. ...
    (rec.games.pinball)
  • Re: AC->DC converter question
    ... Use a 7805 for the 5 volts, ... and power only one regulator at a time, ... I'd drop the voltage between the wall wart and the ... that would be about .96 watts ...
    (sci.electronics.design)
  • Re: Good Will GPS1810OH Power supply problem
    ... Mine has a semiconductor that has the ... a drawing of the ... regulator board... ... Where is the missing relay, and if it isn't missing, then why is ...
    (sci.electronics.repair)