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307
| | Posted on Friday, November 30, 2001 - 9:55 pm: | 
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Why not use a 20 amp fuse in place of the 2 amp?
You know there is a lot of people who bring there radio's in for repair and usually it is for getting the polarity diode fixed after it was blown off the board because someone swapped the 2 amp fuse for a 20 amp fuse and hooked the radio up backwards . This is not a good idea and I have actually heard some CB shops say that the radio will put out more power if the fuse has a bigger rating because it lets more electrical current flow through it . This is a very un-true statement .
In most all CB radios in the rear towards the power connector there is a small black diode , usually a 1N4001 or similar in value that is placed there for a good reason . If you get in a hurry hooking up the red and black wires to the battery and you just happen to touch the red to the negative of the battery and the black to the positive of the battery , you will reverse polarize the power input to the radio and that's where that little diode takes over . A diode only lets current flow one way so when it is backwards , current is drawn through the fuse and it blows , that is if it is the correct one . A 20 amp fuse will not blow but the diode will . In most cases the diode will fuse in the shorted mode and then you have a dead short on the power . No matter if you place the wires on the battery correctly , the damage is already has been done and it will continue to blow the fuse or melt the power wires . The best thing to do is put an 8 amp fuse in line with Export radios and a 4 amp fuse in the standard radios . This way if you hook it up backwards the fuse will blow and not the radio . It takes a CB shop all but 2 minutes to replace the bad diode and charge you 35 dollars .
If you are still color blind and have a problem hooking red to red and black to black then try these simple little tips and maybe it will help . Always hook up the antenna LAST . When it is hooked up first , you have an automatic ground it most cases and if you touch the black wire to the positive on the battery you will have smoke . so hook up the antenna last. Remove the fuse while hooking it up . This only takes about 3 seconds and can save you big bucks .After you hook up the radio , look to see if red is positive and black is negative . Then hook up the antenna and then put the fuse in . If you are still blind and can not see the "+" and the "-" on the battery , use some "white out" as a high lighter and paint the "+" and "-" markings on the battery . This works well in dark environments as well. |
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