[Elecraft] KPA500 RX Attenuation and TX Without Amp Key

[Jack Brindle]

Mark;

Recheck the ribbon cable connections in the amplifier. This sounds like a connector
is off, either to a side or more likely one complete row of pins is off. My suspicion
is the 14-pin cable going to the front panel, but it could be the larger cable going
to the IO board. You also might try reseating these cables to make sure they are
connected properly.

- Jack Brindle, W6FB
Elecraft Engineering

> On Nov 15, 2015, at 12:24 PM, Mark Goldberg <marklgoldberg at gmail.com> wrote:
> 
> I will contact Elecraft tomorrow, but posting in case someone
> recognizes the symptoms.
> 
> I just put together a new KPA500 kit. When I select Operate, the RX
> through the amplifier is significantly attenuated, many 10s of dBs.
> The amp will also amplify even with nothing connected to the PA Key
> RCA jack. It seems to amplify OK, 35W in gives 400W out. In Standby
> the RX and TX pass through the amp as expected.
> 
> It seems to me that it thinks PA Key is enabled all of the time, so
> when I switch to operate it is in TX mode immediately. I do not see a
> short at the RCA jack.
> 
> Any idea of what is going on?
> 
> Mark
> W7MLG
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