FT817ND Only powers with Ant conntected

My FT817ND has developed a fault where it needs to have the antenna plugged in else it powers off. It also seems to be ignoring the key when it is connected.

Has anyone got any ideas of where to even begin with diagnosing this?

I tried a factor reset and it is still the same!

Thanks and 73

 

Is it a mobile installation?
If it is check the negative connection on the power lead, it could be using the coax outer as the negative connection. Also examine the end of the power plug, they break right at the tip and sometimes leave a bit if insulation inside the radio.

 

On the non-ND, the power leads go through a toroid (noise filter) before connecting to the board. I just fixed one where one of the windings in the negative lead, and a trace on the board opened up. I only had the DC plug in. If I would have connected an antenna that shared a ground (albeit a long path) with the power supply, I bet it would have turned on.

Download the service manual and check from the DC jack on the back through the first few traces of the negative circuit on the board.

 

Yes, I suspect there's a break in the negative power lead, and it's grounding through the antenna shield.

As for the key being "ignored," I forget right off hand, but I believe there's a menu setting that configures the key plug depending on whether you have a straight key or paddles.

 

Thanks for the replies everyone. I will check the negative lead as this does sound likely.

Just to clarify it is not a mobile installation and it is the ND version.

I have checked all menus for the key. I do have a feeling it is somehow related. I guess I will find out if I manage to resolve the turning on issue.

 

I have been working on testing this out.

There is no issue with the lead as I have checked the voltage on the board side of the DC jack and I get the correct voltage. There is nothing visibly different with the board.

If I plug an antenna in I can use the outer (or indeed any of the metal housing) as the negative to measure voltage. If I remove the antenna then the voltage slowly ticks down to zero again. The whole time the DC jack is giving the correct voltage.

Any ideas?

Edit: it all works as normal using the internal battery pack

 

I had a similar problem with my Icom. I have a inline 12v protection device and one of the PowerPole pins was pushing back (negative)

Sounds like you have a high-R connection on the negative side.

 

The resistance is same on both the positive and negative lead as measured from the board to the powerpole connectors. I can't think what else would be causing this

 

What does that mean ?

Is the radio set for Auto Power Off ? APO

 

I have a schematic for an ND model, and it shows the power input toroid that AA3EE refers to. Try an external 12v battery and see if the "antenna connected" fixes it. If no 12v battery is available, try any antenna that has no ground involved. Only a few things from 12V in to the rig. The jack, some PCB traces and the toroid. Or, try jumping the PSU negative directly to your rig's ground lug.
Mike N3PM