Why Ryobi finish gun stopped working?

Test the volts and amps of the battery after charging, then try to shoot nails then test again after the blinking orange light. Battery is failing, they only have a certain number of recharge cycles and are also governed by age degradation.

https://www.google.com/search?q=hitachi+nailer+battery+problems+and+solutions

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Battery is weak. Those lights are really useless...more a marketing gimmick. It almost sounds like it developed a memory...this happens when certain types of batteries are not fully discharged before being placed on the charger. Replace the battery and make sure to follow charging directions for that particular type of battery

Glad to see you are up and running again.

If you charge the battery for more than five hours or over night, you'll burn out the battery. When your done playing with the gun dont put it on the charger immediatly as this will overheat the battery. Wait about an hour for the bettery to cool and then put it on the charger. It should work fine after that.

when pressed down the main switch is activated, so switch could be faulty or connections loose

Your camera probably needs a new battery.
The light meter needs sufficient power (5.5v to 6v) to work correctly.

Your ISO could have moved, even a double or halving of it will over/underxpose a full stop.

try a new battery m8 when they have been used fir a while they wear out at the catch and when u fire the nail gun the battery works its way out enuf to stop it making a good contact. Hope this helps.

Solution is two fold. Will try the freeze and re charge approach today and do this a few times. The long term soluiton is to purchase two Lithium batteries and a duel chemical charger. Expensive solution but seems it will work.

The most common cause for what you are seeing is a shorted gun in the picture tube. When 2 elements (heater and cathode) of one of the guns inside the neck of the picture tube touch, that gun goes full on and overloads the flyback (high voltage) transformer. If it is in the blue gun, the screen will go bright blue with light blue "retrace" lines in it. The computer senses the overload and shuts the set off. At 2 years old the tech most likely tried removing the short by arcing between the elements. This works sometimes but the short often comes back a few months later. Another attempt at removing the short could be tried, and it might work this time, but it may or may not work for long. The ony other solution is to replace the picture tube but that would cost much more than the set is worth. A qualified tech will be able to tell you if this is the problem in your set.