Need Help Diagnosing Faulty IR Signal on Universal Remote

[losting]

Hi all,
I?m currently troubleshooting an old universal remote (URC-6131) that?s stopped sending IR signals. The buttons register clicks, and the LED flashes normally, but no signal reaches any of my devices.

Here?s what I?ve tried and observed:

Checked IR LED with a phone camera ? it?s not lighting up.

Measured voltage at the emitter ? fluctuates briefly, then drops.

Swapped out the two electrolytic caps near the output circuit ? no change.

Crystal oscillator seems intact but not sure how to confirm it's still functioning correctly.

Could this be a failed transistor or crystal issue? Or something upstream with the microcontroller?s output?

Any help or common failure insights would be greatly appreciated. I have basic soldering gear and a multimeter, and I?m comfortable replacing small components if needed.

Thanks in advance!