[TenTec] Omni VI troubleshooting ( TX trips PS breaker )

[Dr. Gerald N. Johnson]

On Sat, 2007-10-13 at 22:52 -0500, Michael Pfeuffer wrote:
> Hi all,
> 
> My Omni VI has developed a problem.  Does anyone recognize these symptoms?
> 
> 1) RX seems fine
> 2) any TX immediately trips off the power supply ( model 961 )
> 3) power cycling the PS restores everything
> 4) occurs with minimum power out
> 5) the power supply is OK - it drives another rig to 100W without tripping
> 
> Any thoughts or suggestions before it gets sent back to TT?
> 
> Thanks!
> --Mike, WQ5C
> 
Wouldn't be shorted PA transistors since they have power applied all the
time. Could be bad PA or driver bias circuit that puts too much forward
bias on one of those transistors.

Could be the driver or PA is oscillating. First test is to lift the lid
and tighten all the PC board mounting screws that are generally the
board grounds also. With pressure through the plastic board material its
acted up to its name and relieved that pressure. I've fixed many a radio
that way both locally and remotely.

Could be a short on the switched TX voltages anywhere in the
transmitter. May have to isolate by separating circuitry.

73, Jerry, K0CQ