Cobra 29 Blows fuses

[Charger383]

Did you check the diode in or out of the circuit?



I would pull it anyway and replace it and see what happens.



If it still does it, chances are you could have an audio amp that has shorted or even a final.



An easy way to check these are:



1: unsolder the legs on the final and then power the radio up. If it does not blow a fuse, then you have found your culprit.



2: Unsolder the legs to the audio amp and see if the same thing happens. It should be a TA7222AP mounted to right hand side of the radio.

</p>Edited by: <A HREF=http://pub86.ezboard.com/ucharger383.showPublicProfile?language=EN>Charger383</A> at: 9/16/02 7:07:39 pm

 

[Charger383]

Did you check the diode in or out of the circuit?



I would pull it anyway and replace it and see what happens.



If it still does it, chances are you could have an audio amp that has shorted or even a final.



An easy way to check these are:



1: unsolder the legs on the final and then power the radio up. If it does not blow a fuse, then you have found your culprit.



2: Unsolder the legs to the audio amp and see if the same thing happens. It should be a TA7222AP mounted to right hand side of the radio.

</p>Edited by: <A HREF=http://pub86.ezboard.com/ucharger383.showPublicProfile?language=EN>Charger383</A> at: 9/16/02 7:07:39 pm

 

[range rider]

Have you tried a different power cord?

RCI 6900FTB

X-Force 400HD

Mr Coily single coil

Wilson Silverloads

RK 56

CDX-878 Lone Star mobile

2DK57
</p>

 

[range rider]

Have you tried a different power cord?

RCI 6900FTB

X-Force 400HD

Mr Coily single coil

Wilson Silverloads

RK 56

CDX-878 Lone Star mobile

2DK57
</p>

 

[211 in tha mag]

Here is what you do, sometime when a radio has been "PEAKED AND TUNNED" that 2 amp fuse is not enough! Put in a 10 amp or a 12 amp fuse, and you arre ok!!!!

"CDX-401" </p>

 

[211 in tha mag]

Here is what you do, sometime when a radio has been "PEAKED AND TUNNED" that 2 amp fuse is not enough! Put in a 10 amp or a 12 amp fuse, and you arre ok!!!!

"CDX-401" </p>

 

[211 in tha mag]

well, thats crazy!!! I have always ran 10 amp.s without a problem, i guess i need to put in those 4 amps! Reason why i use to use 10 amps is because a LONGGGGGG, time ago a tech told me to use them, so i guesss im going to make that switch, sorry for the wrong advise, i did not now!!!

"CDX-401" </p>

 

[211 in tha mag]

well, thats crazy!!! I have always ran 10 amp.s without a problem, i guess i need to put in those 4 amps! Reason why i use to use 10 amps is because a LONGGGGGG, time ago a tech told me to use them, so i guesss im going to make that switch, sorry for the wrong advise, i did not now!!!

"CDX-401" </p>

 

[The Defpom]

Hi,

Firstly D44 is actaully an 18V Zenor diode, only replace it wih another of the same value otherwise it will not protect the IC's next time it happens.



As for fuses the rating may say 4A but they have a fusing factor of 2.5, which means that it will take up to 10A before it blows within 1 minute !



The radio will probably only pull about 3-4A anyway, so use a 5A fuse, it you use a 10A the current can go as high as 25A for one minute before it will blow, this would occur if something like an audio amp or final blew, only it would destroy the circuit board before the fuse blows, also bearing in mind that in RX the radio will only be drawing about 0.5A anyway, so if a 2A fuse blows THERE IS A FAULT.



I think that it is D44, that is a part that often fails if a radio is reverse wired and the power switch is turned on, it is there to try and protect the voltage regulators and other IC's, and it does often do as it was designed to do, but sometimes it will not handle it, like if someone has used a massive fuse, all of that current will flow into D44, if it is too much it will destroy the diode and then start with the IC's !



Do you understand why it is so important to only use the correct size fuse ?



If the fuse blows, something is WRONG !




The Defpom


http://www.radiomods.co.nz/


http://www.TheDefpom.com


http://www.radiodiagrams.com</p>

 

[The Defpom]

Hi,

Firstly D44 is actaully an 18V Zenor diode, only replace it wih another of the same value otherwise it will not protect the IC's next time it happens.



As for fuses the rating may say 4A but they have a fusing factor of 2.5, which means that it will take up to 10A before it blows within 1 minute !



The radio will probably only pull about 3-4A anyway, so use a 5A fuse, it you use a 10A the current can go as high as 25A for one minute before it will blow, this would occur if something like an audio amp or final blew, only it would destroy the circuit board before the fuse blows, also bearing in mind that in RX the radio will only be drawing about 0.5A anyway, so if a 2A fuse blows THERE IS A FAULT.



I think that it is D44, that is a part that often fails if a radio is reverse wired and the power switch is turned on, it is there to try and protect the voltage regulators and other IC's, and it does often do as it was designed to do, but sometimes it will not handle it, like if someone has used a massive fuse, all of that current will flow into D44, if it is too much it will destroy the diode and then start with the IC's !



Do you understand why it is so important to only use the correct size fuse ?



If the fuse blows, something is WRONG !




The Defpom


http://www.radiomods.co.nz/


http://www.TheDefpom.com


http://www.radiodiagrams.com</p>

 

[xxxz5]

Someone gave me a 29 that blows fuses. 1st thing I checked was the revers polarity power diode, it isn't that. The short across the power jack only occurs when the on/off switch is turned on....... Any ideas??


</p>

 

[xxxz5]

Someone gave me a 29 that blows fuses. 1st thing I checked was the revers polarity power diode, it isn't that. The short across the power jack only occurs when the on/off switch is turned on....... Any ideas??


</p>

 

[Happy Hamer]

this was asked in the chat room by STONE

Look at the answer by defpom this was asked in the chat room

</p>

 

[Happy Hamer]

this was asked in the chat room by STONE

Look at the answer by defpom this was asked in the chat room

</p>