[ICOM] Repairing a IC-471H

[Bill NY9H]

john,

I have had the same failure mode two times in different VHF Icom radios 
both in the module. The ceramic substrate cracked which cracked a circuit 
trace.
Once it was a wide trace carrying 12vdc. The other time it was a different 
trace.
Once the crack was visible to the eye, the second time , I needed a magnifier.

I was able to pull the "cover" off the module while leaving it still connected.

Then I floated solder , bridging the crack...
I can't recall if I used silver solder, or even if I should have .
But it fixed it ... both times.

bill


At 10:00 PM 10/12/2004, John wrote:

>Well my trusty 471H has stopped putting out RF. It appears to put out a 
>VERY small amout, too small for a Bird to register, as I can hear it on a 
>hand held on the output frequency.
>
>There is voltage in all the right places in the PA module except the 
>output volts on IC 1, which seems to be a power module.
>Does anyone know what the input/output power levels of this module is ? I 
>guess it has to be about 10-20watts out to drive the final. Also what is 
>HV and PAV on J1 in the PA. Could a failure in the power control circuit 
>be the cultprit? How can I test it
>
>I'd like to try and save it
>
>--
>John Mc Hugh, K4AG
>Coordinator for Amateur Radio
>National Hurricane Center, WX4NHC
>Home page:- http://www.wx4nhc.org
>
>
>
>
>----
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