XV-144 Overdrive protection

[Andrew]

Hello

Just starting Part VI-Filter Alignment, other tests prior worked no problem.

Using a KX3 on 5 watts with XV-144 set to 5 watts input.
With key line and coax from ant socket (kx3) to XV-144.
Dummy load via power meter connected to output of XV-144.

The XV-144 goes into overdrive protection whatever power I apply to the input all I get is the power led's flashing on the front panel.

Any ideas where to look, am I missing something?

Thanks

Andrew   GM0UDL

[Don Wilhelm-4]

Andrew,

Some transverters suffer from false overload detection due to noise on
the DC circuit to the microprocessor.
The cure I have found effective is to remove the front panel metalwork
and solder a 0.1 uF capacitor between the collector and emitter of Q7.

If you do not have the two 0.1 uF capacitors on the 5 volt regulator and
the 10 uF electrolytic across the 5 volt line (between pins 1 and 2 of
the main board P1) they should be added as well.
See
http://www.elecraft.com/Apps/XV_Bypassing_Cap_Builder%27s_Alert_Rev_A.pdf

73,
Don W3FPR

On 2/13/2014 5:09 PM, Andrew wrote:

> Hello
>
> Just starting Part VI-Filter Alignment, other tests prior worked no problem.
>
> Using a KX3 on 5 watts with XV-144 set to 5 watts input.
> With key line and coax from ant socket (kx3) to XV-144.
> Dummy load via power meter connected to output of XV-144.
>
> The XV-144 goes into overdrive protection whatever power I apply to the
> input all I get is the power led's flashing on the front panel.
>
> Any ideas where to look, am I missing something?
>
>

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[Andrew]

Don,

Thanks for the reply.
I have the capacitors on the reg and the electrolytic cap on pin 1 and 2.
I am using a separate supply on the XV-144 compared to the KX3, will try using the 1 supply.
Then I will fit a 0.1 uf  on Q7.

Thanks

Andrew GM0UDL

[GM0ELP]

I have seen this before when the 2.5mm key line jack just needed pushed firmly home. A 2.5mm jack doesn't have the mechanical resistance to stay in by itself. There is also a pesky metal ridge round the socket on the kx3 which causes some jack designs to disconnect when rotated. TX without the key line causes the front LEDs to flash.

[Andrew]

GM0LEP,

Thanks for that I have run out of time as I am due to go away to work for 6 weeks or so.

I will check that the PTT line is working and may try another radio as a driver also.
Will keep all posted later on here.

thanks

Andrew  GM0UDL