Icom 706 Shuts down

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pbeezy

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So I have a Astron 30 Amp power supply and a 25 amp Power supply.


When the Icom 706 is connected to the 30 amp power supply the radio will shut off when the power setting is above "3" The volts on the power supply decrease to around 6 and the Icom will shut off.

When I attach it to the 25 amp power supply I can broadcast at full power but I get a noise from the internal speaker in the radio.

Is my radio brokes?

:-(

Any help would be appreciated as to why it shuts down on the bigger supply and why the noise from the internal speaker on the smaller supply, and any suggestion to resolve it.

SWR by the way is flat on 2 meters.
 

w2txb

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Sep 22, 2006
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"RF in the Shack"?

So I have a Astron 30 Amp power supply and a 25 amp Power supply.


When the Icom 706 is connected to the 30 amp power supply the radio will shut off when the power setting is above "3" The volts on the power supply decrease to around 6 and the Icom will shut off.

When I attach it to the 25 amp power supply I can broadcast at full power but I get a noise from the internal speaker in the radio.

Is my radio brokes?

:-(

Any help would be appreciated as to why it shuts down on the bigger supply and why the noise from the internal speaker on the smaller supply, and any suggestion to resolve it.

SWR by the way is flat on 2 meters.
Despite a low SR, you may have a lot of RF getting back through the power supply - even the Astron units can have this problem. The RF may be carried through audio cables, digital controllers (i.e., RigBlaster), etc. Check your grounding as well.

I use a copper pipe as a ground bus with copper braid connecting it to the radio (IC-7000) and tuner (Palstar AT-AUTO), then run a heavy wire to three earth grounds. I also tightened all the ground connections in the Astron PS, and added a few ferrite chokes (Steward units from Mouser). Since then, no problems whatsoever.
 

W2NJS

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Are your power supplies transformer or switching type? The switching type are sometimes susceptible to RF getting into them. The transformer type are usually not. Another thing to look for is a bad regulator circuit on the PS that drops its voltage under load, typical behavior for a PS whose regulator is inoperative. Astron sells both parts and complete replacement boards, but you'll have to dig into the unit and find out what's happening, or not happening, to the unit when it's under load. The speaker problem sounds like RF getting into a switching power supply and then getting into the radio via the power cable. Another thing to be aware of about funny noises coming from a speaker in today's RF receiver setups is the proximity of computer processors to the receiver. Many a problem has been solved by moving equipment items farther apart.
 

ramal121

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All good answers. Don't think there is any prob with the 706, just the power supplies. The 30 amp is not giving you all 30 worth. When the voltage sags to 6V, the Icom cannot run at that voltage and shuts off. The 25 amp is just noisy, either internally or being subjected from high SWR. Suspect that is a switcher type.

Can you borrow or steal a charged car battery? You could jimmy it up to the Icom and see how well it plays. If all is good, repair or replace the power supplies.
 

n8emr

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Oct 20, 2005
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498
The problem is not the supply. Its RF getting back into the radio.... Its a common issues especially on 20m, but can be seen on all bands. Shorten up or move the power cables away from the RF path.
 
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