[TenTec] triton 540 reversed polarity

[Louis A. Ciotti Jr.]

Thanks for the information.  I have located the manual which has a schematic.  I guess I am going to have to dig in and start changing parts.

I do not think I destroyed every IC as the radio powers up and the remote digital readout I have for it works and shows the correct frequency so some portion of it is working.  That and the fact that I can still hear static if I turn the volume up to max means that some portion of the receiver is working.  

Thanks again, and keep the ideas comming.  

73
Lou
KC2RVD

  
-----Original Message-----
From: "Dr. Gerald N. Johnson" <geraldj at storm.weather.net>
Date: Tuesday, Aug 7, 2007 12:21 pm
Subject: Re: [TenTec] triton 540 reversed polarity
To: tentec at contesting.com

On Mon, 2007-08-06 at 21:24 -0500, Stuart Rohre wrote:
> Reversal of DC polarity may have failed some electrolytic capacitors.  Also, 
> if it is working weakly, maybe a diode in a bridge rectifier is open.  How 
> long was the polarity reversed?  That may tell if any active devices bit the 
> dust.
> 
> -Stuart
> K5KVH 
> 
>My experiences with reversed polarity is that the fuses are reliable
>indicators of fried semiconductors. That semiconductors fail faster than fuses open, so time isn't much of a factor.
>
>ICs dislike reversed polarity and often short. Some ICs running off internally (to the radio) regulated voltages may be protected by the
>regulators, some regulators may feed full supply under reversed polarity conditions. Small bipolar transistors base-emitter junctions often
>(especially RF types) have lower break down voltages than the inverted supply and the avalanche can do serious junction damage.
>
>Expect to test and maybe have to replace every IC and every transistor along with many electrolytic capacitors. And the miniature electrolytics may have been poor anyway just from age.
>
>-- 
>73, Jerry, K0CQ,
>All content copyright Dr. Gerald N. Johnson, electrical engineer
>
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