Garmin GDU 4xx Upgrade 8.72 to 8.81 and GLD39-R Issue?

Has anyone encountered an issue after upgrading a GDU4xx from version 8.72 to 8.81, and then have a GDL39-R stop reporting traffic? I see from the archives (Apr 2020) this was an issue in an earlier version of the GDL39 software (4.9), and fixed in 4.91.

I recently performed the GDU4xx upgrade to 8.81 and I believe this is when the RS232 Port 1 on the GDU4xx stop working (red x). My backseat passenger using a connected iPad reported a firmware upgrade is needed on the GDL39-R. I am curious if anyone else has seen this issue. I have a trouble ticket (so to speak) with Garmin.

thank you

Chris,

GDL 39R V4.91 works great with G3X Touch V8.81.

Are you sure you have good wiring and power to the GDL 39R and the RS-232 port on the GDU 4XX configured for Garmin Data Transfer?

Steve

GDL39R

An update... this appears to be a INOP GDL39R. The GDL does not show as a device in Config Mode > System Information > Devices. In the RS232 Option, port 1 is configured for Garmin Data Transfer, but shortly after system power up, it displays a red X. I test power at the Dsub connector for the GDL pins 5 and 9, I have 12.49 volts on the multi meter. Attempted to connect from the GDU460 to the GDL via bluetooth, but the GDL is not found in the GDU search.

In looking for a replacement for the GDL39R online, it appears these have been replaced by the GDL50R... I am confirming with Garmin.

Continuity problem - between the ears

So,,, this was an interesting journey. Per Garmin advice, I disabled the RS232 on port 1, so I could Bluetooth from the GDU to the GDL for the software update. This worked, and the GDL was updated from version 3.1 to 4.91.

I then tried to connect using RS232 to the GDL, but no joy, just a red x on the RD232 Config Page for Port 1.

Port 1 was the only port configured on the GDU, and it was set for Garmin Data Transfer.

I removed the connector for the GDU, and tested continuity for pins 47 and 48, to pins 2 and 3 respectively for the GDL... found none... What the heck is going on here - lol. Garmin had suggested moving to another port on the GDU to isolate the issue, I decided to remove the wire and inspect first. Disassembled the GDU connector to unpin the wire, and realized the wire did not go to the GDL, it went to the GMC305. Certainly explains the lack of continuity to the GDL.

I inspected the GDU connector for port 2, pins 14 and 30, and found pins in both. Tested continuity to the GDL pins 2 and 3, and it worked.

Reassembled everything and configured port 1 for Garmin Data Instrument for the GMC305, and post 2 for Garmin Data Transfer for the GDU. Now have green checks by both on the RS232 Config Page.

This has been wrong since day 1? I did all the wiring, so... but I recall receiving traffic call outs, especially while flying near Thomaston, GA during Phase I, so, well, really baffled, but nonetheless, now all appears to be working.