Transponder Warning Message - TX PSU LOW (0)

[Josh_Westbrook]

I installed the Dynon Skyview Touch System in my airplane a few months ago, and I'm still getting familiar with it. I haven't flown yet. Hopefully getting my airworthiness in the next month or so.

I'm getting a transponder warning message which reads "TX PSU LOW (0)". I read the installation guide and another forum post which says this is a power supply problem, but I have also seen that the values at the end of the message mean different things.

Any idea what the "(0)" means, or what I should do to correct the warning message?

Thanks,
Josh

 

[chipf]

I recently started having a similar issue.
In my case the transponder warning says
TX PSU LOW (18)

This is a -472 transponder installed in 2011.

Just wondering if this is an equipment issue or do I need to trouble shoot my electrical system. The EMS page tells me that the bus voltage is healthy, but I haven't started any further diagnosis.

I will have to upgrade to the -471 sometime next year. Its probably too much to ask for that a new transponder fixes the warning!

 

[Josh_Westbrook]

Below is an email response I received regarding the issue. I checked both the antenna and ground connections and that still didn’t solve the problem. Initially I had a 262 transponder. Knowing I wanted to upgrade to the ads-b capable 261 transponder anyway, I contacted Dynon to see if they had an upgrade program. They directed me to Mid-Continent Avionics mcico.com . They will upgrade your current unit from a 262 to a 261 for $900 +s&h. When they did mine they actually found a compentent that was faulty and needed to be replaced. They corrected the issue for free, and my transponder works perfectly now.

I must say that I DO NOT believe the issue I was having was caused by Dynon and I do not blame them for anything. After reading the manual more carefully, I saw that the tx is very seciptiable to damage from static sock. I don’t believe I was taking proper care to prevent this during installation. I also installed a direct ground to the case of the TX after it was fixed and reinstalled to prevent this from possibly happening again. Dynon and Mid-Continent were very helpful and I can’t thank them enough.

Hope that helps. Good luck!

“Hello Josh,

The TX PSU LOW message means that an internal power supply output voltage is incorrect, as measured by the transmitter diagnostic logic. This is indicative of either an internal fault, or a low supply voltage. I recommend confirming that you have a high quality ground connection between the transponder case and aircraft ground. This circuit should have very low resistance.

The TX POWER LOW message means that to much power is being transmitted back into the transponder via the coax shield, as measured by the transmitter diagnostic reverse power detector logic. This is likely due to issues with the antenna installation.

Best regards,

Rick Ludtke
Dynon Avionics Technical Support
support@dynonavionics.com
Phone: 425-402-0433 - 07:00-17:00 Pacific weekdays”

 

[kellym]

I recently started having a similar issue.
In my case the transponder warning says
TX PSU LOW (18)

This is a -472 transponder installed in 2011.

Just wondering if this is an equipment issue or do I need to trouble shoot my electrical system.  The EMS page tells me that the bus voltage is healthy, but I haven't started any further diagnosis.

I will have to upgrade to the -471 sometime next year.  Its probably too much to ask for that a new transponder fixes the warning!

You are confused on model numbers. 470 and 472 are ADS-B IN receivers. The transponders are 261 and 262.

 

[swatson999]

I recently started having a similar issue.
In my case the transponder warning says
TX PSU LOW (18)

This is a -472 transponder installed in 2011.

Just wondering if this is an equipment issue or do I need to trouble shoot my electrical system.  The EMS page tells me that the bus voltage is healthy, but I haven't started any further diagnosis.

I will have to upgrade to the -471 sometime next year.  Its probably too much to ask for that a new transponder fixes the warning!

You mean the 262 XPDR, and the 261 Class 1 XPDR? 472/471 are the ADS-B In boxes.