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.
BCD396XT/BCD996XT: Need help/opinion
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tvengr
Well Known Member
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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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
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
FreqNout
Member
Unlikely that you will be able to repair the unit without a schematic. Applying AC to the DC input could have caused simple or major damage. Best to send in for repair.
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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.
FreqNout
Member
The specs you posted say 18VAC output. This applied an AC voltage to the DC input. Good luck with your troubleshooting.
tvengr
Well Known Member
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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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!
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
Member
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
wtp
Member
if i see it right, there is a 12V 3pole connector on the back near the plug in power.
could you try that before boxing it up ?
could you try that before boxing it up ?
Ubbe
Member
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
Member
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.
Here’s my latest update on my Uniden scanner: Well it looks like the scanner and rotor motor and controller was hit by lightning. So now I’m ready for a replacement of the BCD996XT. The antenna rotor motor has been replaced. I’m looking at the SDS200. Does anyone have an option of this radio and has the humming migration been fixed by Uniden? The only place I see where they are available is from bearcat but who knows how long they have been on their shelf. Would rather buy from scannermaster but there out of stock.
Bearcat Warehouse ? They are a retailer like ScannerMaster and have been going in and out of stock like every retailer, so it's doubtful their stock is old.
Try using the 3-wire cable if you still have it. I fried the small power connector on a BCT15 some years ago and the radio still works fine using the 3-wire connection still works fine.
These two power connections have separate power protection, it might be that just the one is popped.
I was told on here to try it in the car so I did and the radio lit up but then started to smoke. By the way what is the 3-wire cable?
What did you use to power it up in your car?
The "three wire" cable Rich mentioned is the wiring harness you'd use if mounting the scanner in a vehicle/ Besides positive & negative leads., it has a third wire (orange, if I recall). The positive & negative leads are your power & ground connections, The third wire is used to connect to the dash lights circuit of the vehicle, to automatically dim the display when your headlights are on. This connects to a matching connector on the scanner.
There are two other power cords that shipped with the scanner. The AC adapter, and the 12VDC cigarette lighter cord, both use the same plug in port on the scanner. So, if you used the lighter adapter, that's feeding power to the same circuit in the scanner that was damaged by your overvoltge (mentioned above).
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