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#1
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Scanner Bearcat 250 Help!
My mothers friend wants me to try and fix a older Bearcat scanner
model 250 that shuts down after being on about 20 minutes. After the cool down it seems fine. Everything works well otherwise. What to look and change for myself help is appreciated. Nick |
#3
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Get a soldering iron, turn on the radio and start heating components until
it quits. Replace the one that caused it. Normally it will be a capacitor that is the problem. Sorta like tune for maximum smoke and replace all charred components. ;) "Nick" wrote in message ... My mothers friend wants me to try and fix a older Bearcat scanner model 250 that shuts down after being on about 20 minutes. After the cool down it seems fine. Everything works well otherwise. What to look and change for myself help is appreciated. Nick |
#4
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Bob; I took out the power transistor with the 3 leads soldered and
can't find one now. Rat Shack does not have them and still looking on net. It was real hot if that was proble, Allaround it seemed blackened from heat but not blown. Hope that is what it is. Not even sure of name. Would sit under the soldered side under the power transformer and from the underside near the largest can capacitor and has a tri axial lead near the squelch wire solder point. It has a hole on top but no heat sink of any kind to disapapte that kind of heat. Says from what is readable Texas Instruments and some number but no rating etc. Any more help here. nick |
#5
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Nick, I have a number of BC250 scanners and replaced that transistor with a
3 terminal regulator in all of them. They've been running that way for at least 15 years. I used 7808 - 8v regulators and used the 16v terminal on the On/Off switch. I drilled a mounting hole in the chassis and ran the wires from there. The collector of Q204 was the 16v line and the emitter is the 8.4v output. The original transistor is a T.I. TIP 29 Rich "Nick" wrote in message ... Bob; I took out the power transistor with the 3 leads soldered and can't find one now. Rat Shack does not have them and still looking on net. It was real hot if that was proble, Allaround it seemed blackened from heat but not blown. Hope that is what it is. Not even sure of name. Would sit under the soldered side under the power transformer and from the underside near the largest can capacitor and has a tri axial lead near the squelch wire solder point. It has a hole on top but no heat sink of any kind to disapapte that kind of heat. Says from what is readable Texas Instruments and some number but no rating etc. Any more help here. nick |
#6
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I should have mentioned that you can use an NTE964 as a sub for the 7808.
NTE964 Integrated Circuit 3 Terminal Positive Voltage Regulator, 8V, 1A http://www.nteinc.com/specs/900to999/NTE964.html Rich "Rich" wrote in message ... Nick, I have a number of BC250 scanners and replaced that transistor with a 3 terminal regulator in all of them. They've been running that way for at least 15 years. I used 7808 - 8v regulators and used the 16v terminal on the On/Off switch. I drilled a mounting hole in the chassis and ran the wires from there. The collector of Q204 was the 16v line and the emitter is the 8.4v output. The original transistor is a T.I. TIP 29 Rich "Nick" wrote in message ... Bob; I took out the power transistor with the 3 leads soldered and can't find one now. Rat Shack does not have them and still looking on net. It was real hot if that was proble, Allaround it seemed blackened from heat but not blown. Hope that is what it is. Not even sure of name. Would sit under the soldered side under the power transformer and from the underside near the largest can capacitor and has a tri axial lead near the squelch wire solder point. It has a hole on top but no heat sink of any kind to disapapte that kind of heat. Says from what is readable Texas Instruments and some number but no rating etc. Any more help here. nick |
#7
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Well, I found that regular I spoke of at a small electronics store 25
miles away and soldered it in and no nothing now. No display, volume, sound, squelch. Now what could it be or was I wrong in the first place. Ready to give up on it. It did spark once on the one that is screwed to the fram eon side with wires coming out on a mini male plug if that is any hint. I'm a newbie and really don't have much experience or equipment but trying. Nick |
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