[TenTec] Orion 565 power out problem fixed

[Martin Sole]

Orion 565

Hi,

I noticed yesterday that I had very low power on 160, 3-5 watts, low 
power on 80, lower power on 60 and lowish power on 40, 30, 20 and 17 
were all pretty normal though slightly down on what I recalled, 95 vs 
105 watts on 20m. Power on 15 12 and 10 was also down, 60-70 watts.

So a somewhat frequency sensitive power problem.

I started by pulling the drive cable J5, low level TX out, from A3-81906 
RF converter. Measuring the drive at this point I used the direct input 
mode of my LP-100A power meter and registered around +25dBm on 17 but 
less on other bands, down to around 5dBm on 160. Working back to the 
input of A3 at J3 I measured approximately -5dBm on all bands. From this 
I started to focus on A3 and examine in more detail the signal path. As 
I'm trying to identify parts against the schematic my probe touched on 
R119, the TX mixer balance pot, which I couldn't immediately see on the 
diagram. As I touched it the 160m drive power jumped to +24dBm. A check 
of the other bands showed them all to be roughly similar. Reconnecting 
the PA I now have full power on all bands. I have given R119 a bit of a 
workout and reset it for minimum LO feedthrough.

R119 is another of those blue pots, as found throughout the radio and as 
others have noted can be the cause of problems.

As the radios age and as the pots start to suffer more and more, or so 
it would seem, a reliable replacement would be good to add to the first 
aid kit. Some of this could be attributable to my environment, Thailand 
is super humid, YMMV.

Thought I would post this in case anyone else runs into a similar issue.

Regards
Martin, HS0ZED