Fix for G&G ETU red blinky light syndrome!
Have an ETU that seemingly "burnt out" and just blinks red when you pull the trigger? I may have a solution for you. It may not work in all ETU's because I have only seen/repaired one failed one. On this one it burnt out the trace pointed to by the arrow. A quick bridging of the connection with solder and it was back in business.
If your ETU's trace pictured (or any other trace) looks like poop and burnt out, you may have the same issue.
I've never seen this solution or any ETU solutions posted anywhere on the internet, so I thought I'd share it.
Note that this is a brand new unit, not the repaired one.