RS232 link into HTM MX-700 flakey. Caps?

[Minok]

I've hade this Home Theater Master MX-700 programmable universal remote control for 15 or so years. Served me well. Beauty is one can configure the buttons and macros in a PC application and upload it to the remote. Worked up till now. The past week in the middle is an upload ( hadn't done so in a year) the rs232 transmission failed. First thought was, the cable. So I tried the other remote with the same cable and that transmission works fine. So the cable and PC settings and software are fine. It's got to be the remote.

Diagnosis time. Opened up the remote to look at the jack as the next thought was the 3 conductor 3.5mm aux jack used to connect to the serial cable had a contact spring inside just give up. So testing conductivity between the serial cable db9 connector end pins and the contact pads on the remote PCB itself (with cable plugged in) showed conductivity was solid. The db9 end of the cable pins were conducting to (and only to) the pads on the PCB of the remote.

So now I'm wondering what's going on. As I try to initiate a PC to Remote upload it will fail, the work through a partial upload before failing, the fail then fail the partly work, through several retries. So the Rs232 signaling (3 conductor RX TX GND) is working some of the time but the signaling isn't stable at the PCB side.

As I've seen on a variety of repair videos it's electrolytic capacitors that die of age and there are a few electrolytic caps on the board. Likely failure point for a remote powered by 6v of AA batter power over 15-18 years?

The intermittent failure doesn't seem like a silicon problem. Or is that a real possibility?

Looked for cold solder or obvious part damage but nothing visually sticking out.

Attached is a photo of the PCB of the remote around the jack that brings in the serial data signal and the 3 conductors leading out of the jack  into the PCB.

Any advice ?