Question about Radio Shack TRC-447 CB Radio

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No power what is the number for protection diode on back of circuit board?

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  • Dean Pitts
    Dean Pitts May 11, 2010

    Lol, I didn't read enough on the tags. I just looked at the description, used to people putting it in there. I will try to find it for u.



    Dean

  • Dean Pitts
    Dean Pitts May 11, 2010

    What brand and model of radio do you have? The item number varies by radio.



    Dean

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It it blowing fuses?

Posted on Nov 05, 2008

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Posted on Jan 02, 2017

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Hi. My uhf band cp 200 won't power up because it was placed in a charger .Please tell me what protection diodes I need to replace, and it's proximal location. Thank You.


Chargers have higher voltage ratings than the one it charges. It also lacks the needed filters to supply the exact direct current which damaged your equipment but first check if it blows up your fuses when you connect the power supply. If it does check for Zener Diodes usually connected to the mains of the equipment to simulate the simple crowbar effect of protection. If it does not blow up your main fuse then the fuse might be in the circuit board of your base unit. Zener Diodes are cased in striped crystal that short circuits itself when applied with reverse or higher voltage rating power supplies. You will need a multimeter positioned at continuity to test this. Remove it and replace the fuse then apply power, it will light up but remember to replace the damaged part for protection.

Feb 23, 2016 | Radio Communications

Tip

GET YOUR BLOWN UP RADIO BACK ONLINE.


When you cant get your radio turned on. All it does is blow the fuse imeadiatlly hooking it to power. Most likely it is the (reverse polarity diode). The quick fix is to locate your diode? This diode usually is back behind a coil wound transformer on your board inside the radio and in the general area of where the possitive ans negative plug wires solder to the board! Usually it is black with a silver band around one end. If you clip it on one end or remove it this will restore your radios power. CAUTION:: When doing this ALWAYS use a dual fuse power cord . This will prevent this from happening again by blowing the fuse first. Doing this procedure will remove your thermal protection to the radio thus making it wide open to being fried for good if it ever gets hooked up backwards again. This is my reasoning for the dual fused power cord. Good luck!

on Mar 11, 2015 | Galaxy Radios Radio Communications

1 Answer

Crossed power wires on uniden c b radio


Remove the top, the red wire is + and the black - there should be a small black diode near by, if the wires were crossed the diode is shorted and must be replaced "part of the protection circuitry" check for any open foils on the circuit board, If you are very lucky the unit will come back online.

Mar 07, 2012 | Uniden Bearcat Pro PC78LTW 40-Channels...

2 Answers

Hooked my general lee up backwards heard a pop...what could it have been?


Hi looks like youve blown what we call the dummy diode at rear of radio this will have to be replaced although you can remove this yourself if you need it working pronto so firstly remove both covers of rig ,look closely at circuit board at the rear on the right hand side as you look you will see a black diode with silver stripe remove this ,your radio should operate fine now ,but please make sure you have it replaced as soon as possible as this protects your rig from damage goodluck

Oct 30, 2011 | Connex 3300 240-Channels Base CB Radio

1 Answer

Radio won't power up


The radio was most likely hooked up to power backwards. When you hook up the positive and ground wires wrong, it will blow the polarity protection diode in the radio.

The part is N1004 available at any radio shack. The number on the board is D23. It is located near the back right of the board when looking at the component side of the board. It may look black and burnt but not always. Replace it with another N1004 or better. If in a bind, you can just remove it and it will work again BUT!!!!

If you hook it up backwards again by mistake, it will ruin the radio.

Apr 03, 2010 | Cobra 29 WX NW ST 40-Channels Base CB...

1 Answer

I have a galaxy 88 cb radio that smoke came out from the back side, i dont know if the finals are burnt or bad? how do i find out?


Take the cover off,and look at the inside for any burnt parts. It has a protection diode, a lot of times this will burn protecting other parts from damage,look where the red (hot) wire goes in the radio, there is a diode coming off there, is it burnt, to check the finals you will need a ohm meter,check the circuit board for burnt trace,s....You will need a ohm meter to check the finals, they are mounted on the rail....hope this helps....

Mar 16, 2010 | Galaxy Radios DX- 88HL Base CB Radio

1 Answer

No power to radio wont even turn on


The most likely thing is what we techs call revers polarity. this means that the customer accedently hook up the power in reverse. this happens more often then not. The fix for this is to replace the 1 amp diode that goes between the negative and positive power input on the board. the Diode number is a 1N4007 or any 1amp silicone diode. You will also see that once Blown diode is cut the radio will come back on. this does not mean the radio is fixed what this means is that the shorted diode has been removed from the circuit. which also means the radio has nom protection until the diode is replaced.

Patrick Patterson N5SLI

Jun 01, 2009 | Cobra 29 WX NW ST 40-Channels Base CB...

1 Answer

Magnum delta force


What you saw smoke was the protection diode. I do not have one of these radios and have not worked on one yet, but most radios are the same where the protection diode is located on the pc board, one the components side, close to where the wire from the main power positive pin is soldered into the pc board.

I will have to do a little research to see if I can come up with the number of the diode. I have a couple of diagrams and a schematic from cbtricks.com. If I can not located it from their informaiton, I can contact my supplier Monday to see if he can tell me the number. If you happen to located the burnt diode before I come up with the information, please respond so I will know.

Dean Pitts
Rollin CBs

Nov 01, 2008 | Radio Communications

1 Answer

Radio shack cb radio 21-1703


OK. I do not know the exact number for the diode off hand, because I don't have the same radio in front of me. On most cb radios, this diode is usually located on the component side of the pc board, close to where the positive lead solders to the board. Most of the time when it burns, it just becomes brittle.

If you do replace it on your own. The diode is called a rectifier diode, which you can pick up at radio shack or at partsexpress.com. The part number is between 1N4001 to 1N4008. When installing be sure to observe polarity, making sure that the side with the silver band is facing the direction of the arrow.

If I can help anymore, please don't hesitate to ask.

Dean Pitts
Rollin CBs
rollincbmods@yahoo.com

Jul 17, 2008 | Radio Shack TRC-503 CB Radio

2 Answers

Power was reversed now radio keeps bowing fuse and will not come on


Hello hubcap,

 

When the power was reversed this shorted out one of the components, possibly an Operational Amplifier. This tells me that there is no diode protection and possibly the circuitry is exposed directly to the input power supply. The fix would be to find the shorted component with the use of a schematic and a multimeter. Once you correct the shorted component then if possible you can add diode protection by putting a diode (forward biased direction) in the path of the positive line.

 

Again you will need a schematic, and a multimeter to work on this problem.

 

I hope this helps,

 

Thank you,

 

Shuttle83

Oct 12, 2007 | Uniden PC78ELITE 40-Channels Base CB Radio

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