[ICOM] IC706 mk11 G

[Phil Krichbaum]

Wayne,
    Your problem sure sounds identical to mine but there may be more 
than one cause of this symptom. I had the same problem in my vehicle or 
with two different 13.8 VDC supplies in the shack. It turned out the 
trace was pulled of the board, probably due to the number of different 
4WD vehicles the 706 has been in over many years here in western 
Colorado and I live a mile from the nearest government maintained road. 
I often need 4WD to get in here even in the summer when it rains. Winter 
is automatic 4WD every day at 6000 ft ASL in the banana belt.
    Phil N0KE

    Phil

Wayne Johnson wrote:
> Thanks to those who replied to my post.
> Phil and Simon, thanks but the 2 power supplies I have tried are very 
> 'Stiffly' regulated, the one that the radio is connected to at present 
> is sitting at 13.77 volts while on rec, with full carrier the supply 
> sags slightly to 13.75 volts, and that's measured at the pcb where the 
> heavy DC leads terminate.
>
> I had already ruled out low voltage as the problem occurs while at rec, 
> ie tick, tick, tick of the small relay and no display etc.  When the 
> radio is operating normally all functions work with out any problems, it 
> seems as though the switch on relay is failing to latch properly, or to 
> be more correct, comes out of latch when the condition starts. When this 
> happens there is no or incorrect voltage supplied to the logic circuitry 
> ie through the relay contacts (About > 3-5 volts) and the front panel 
> switch fails to even stop the ticking by attempting to turn off  :-(   
> Substituting my own 706 remote head changes nothing so it's not the 
> switch on the head.
>
> Phil, thanks and I did remove the PA pcb and resolder the DC lead 
> termination but alas NG!
> I will now do a bit of circuit tracing to see what supplies the 
> 'holding' voltage to the relay and to try to ascertain why it's not 
> holding. At present as soon as I connect the supply to the connector at 
> the rear it starts tick, tick, tick Grrrrrr!
>
> Anyway it's work in progress, thanks once again and I'll let the 
> reflector know when I sort it out.
>
>
> Cheers
> Wayne
> VK6EH
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