Andromeda drive power drop in low power mode

[SM3PZG]

Hi guys, have a problem that stared occurring a few weeks back. Have Andromeda running Thetis 10.3.6 and protocol 2 v2.2.3.
Have a Expert 1.3K-FA amplifier and it only needs about 10W drive. For some reason drive power began dropping to zero in the middle of TX session. This occurs intermitted so I can make a few QSOs without problem and then suddenly drive power drops a few seconds then on and off. The problem is more frequent as the station gets warmer. Have a extra fan installed so overheating is not a problem.

Turning drive power up to 70-80W the problem disappears so it only occurs with low power drive 5-20W. Same problem in CW and phone as well as just pressing TUNE. Same problem on all bands.

So I figure its might be a hardware problem. Any suggestions?

73/Sam

[SA3ATF]

Hello Sam.

Could it be as simple as resetting the database perhaps?
Usually worth a try anyway.

BTW Have heard you mainly on 15m phone a few times late at night when hunting DX

Good luck anyways

[SM3PZG]

Have tried resetting database and also trying older saved versions of Thetis but that did not help. I think it´s a hardware issue or a bad solder point. Have been running only 5-10W drive for over a year so maybe the hardware doesn't like running idling all the time

[SM3PZG]

Here is a video of the power fluctuation with 10W DRIVE into a dummy load. with 100W power output is fairly stable but sometimes drops to 40-50W. 10W drive is stable when station is cold but start fluctuating as soon as it warms up. Its impossible to use the SPE Expert 1.3K-FA amp that requires 10-15W DRIVE. Same problem all modes including TUNE.

I get the feeling its a hardware issue. The Andromeda has been working fine for 1.5 years. Anyone know someone in Sweden or inside the EU that have the skills to do repair? Apache Labs support is not responding....

[youtube]https://www.youtube.com/watch?v=m-12vimMqvU[/youtube]

73/Sam

[W1AEX]

Hi Sam,

I had a similar issue with my 200D that began to suffer from fluctuations in power at low power levels and when the power level was increased to above 40 watts it was stable. It was very annoying as my amp required very low power levels to drive it and the output was very erratic with the drive level jumping up and down on its own. In my case, the cause turned out to be the internal SMA coax jumpers. The fix for me was to open up the 200D and disconnect and clean each SMA connector with a bit of de-oxit and then re-seat it. It was a tedious job but it paid off as the problem went away and has never returned. I am not familiar with the inner-workings of the Andromeda rigs but I wouldn't be surprised if there are similar internal cables between the mainboard and the RF power amp that might need the same attention.

73, Rob W1AEX

[SM3PZG]

Hey Rob, thanks for the feedback and suggestions. Checking the SMA connectors will be a good starting point.

73/Sam