BCD996XT: Need help/opinion

snapperq

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I have a Uniden BCD996XT scanner. I accidently used the wrong power plug and know the scanner will not work. The wrong AC plug that was used had a larger output. Did I fry the radio or is there a fuse in the radio. Please reply, hopefully with good news.
 

Whiskey3JMC

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Probably will need to be sent to Uniden for repair or sold as-is. I did this once with an Icom, ended up selling it as-is for parts, got about $100 for it non-working
 

tvengr

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I accidently used the wrong power plug and know the scanner will not work. The wrong AC plug that was used had a larger output.
Are you saying that you used a wrong AC adapter that has a higher voltage output? What are the specs of the adapter? Does the (+) voltage go to the center pin? What is the rating of the fuse in the adapter? Scanners often have reverse polarity protection diodes which will blow a fuse if the wrong polarity is applied.
 
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snapperq

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Hello and I appreciate all that replied: The antenna rotor adapter (which was the wrong one that I used) specs are: Input 120VAC 60Hz 29W, Output: 18VAC 1000mA
The scanner adapter specs are: Input: 120VAC 60Hz 0.3A. Output: 13.8VDC 750mA. The scanner was working perfectly until I did this. Did I just blew a fuse in the scanner or is it ruined? Please reply
 

snapperq

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But I didn’t apply AC to the DC input. I just used the wrong AC adaptor which hopefully just blew a fuse. I’ll have to check it out. Thanks for your replies.
 

tvengr

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But I didn’t apply AC to the DC input. I just used the wrong AC adaptor which hopefully just blew a fuse. I’ll have to check it out. Thanks for your replies.
The antenna rotor adapter (which was the wrong one that I used) specs are: Input 120VAC 60Hz 29W, Output: 18VAC 1000mA
An adapter with an 18v RMS AC output would be over 50v peak to peak which could easily damage components in the scanner. If you're lucky, it shorted protection diodes.
 
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K4EET

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But I didn’t apply AC to the DC input. I just used the wrong AC adaptor which hopefully just blew a fuse. I’ll have to check it out. Thanks for your replies.
Please explain yourself in greater detail. Your brief answers are difficult to fully follow exactly what you did where. How do you figure that you didn’t apply AC to the DC input? Please be detailed and include pictures if you can to supplement the words. Thanks!
 

crmaxey

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Probably/Hopefully you just took out the protection diode. Since it is designed for mobile base use they normally have a protection diode right after the power plug inside the radio. There incase someone hooks up power to radio backwards... Any radio shop should be able to check this for you.
 

Ubbe

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There's schematic for the BCT-15x and the 996 are probably very much alike. The input has a diode in series, so the wrong polarity will never reach the electronics. There's a 18volt zener diode that shorts any voltage going higher than that and could have gone short circuit.



/Ubbe
 

Ubbe

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if i see it right, there is a 12V 3pole connector on the back near the plug in power.
It connects to the exact same point to T1 as the other DC jack, just another high ampere diode in series that can handle more amps than what the AC adapter could supply, I.E. diode do not break but the small over voltage protection zener could.

The diodes makes the 18v AC a pulsating DC and the el-lyt capacitor filters the pulsating DC to a more constant DC voltage that will exceed the zeners conducting 18v limit. Too bad it wasn't a 12AC power that the scanner would have coped with, if the BCT15X schematics are indeed similar to 996XT.

/Ubbe
 

FreqNout

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If the OP has the ability, please check the resistance between the DC input center pin and ground. Also, open the case and look for any damage.
 
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