SMD rework station YAXUN 881D

[BobLab]

Hello friends, I have this rework station yaxun model 881D, who only works the iron solder side, the air gun stopped to work and shows nothing on the seven segment display when you turn on the switch, but the fan from the air gun turn  itself on  even if you don't turn on the switch.
What i did so far was unplug the the gun from the socket but the problem isn't in the air gun by the way, i've noticed the voltage regulator heats up a lot.. I never repaired one of this before so i hope some of you guys had the same problem and can help me, thanks !
(The picture i grab from internet but the board is identical).

[BobLab]

nobody?

[thm_w]

Which regulator heats up?

Did you carefully check the output voltage of the regulator (DC), and its ripple (AC), is it as expected?

[BobLab]

It's an L7805CV regulator, I don't have an osciloscope just a analog multimeter who only measure DC voltages and  ..i just measured the output of the regulator and  gives the 5v output, but the regulator quickly heats up, So I removed the MCU from the socket and the heating process stops..Is the MCU shorted? 

[thm_w]

"Heats up", but we don't know how much and if its an issue.

If your analog multimeter can measure current you can measure how much current the MCU is drawing and see if its reasonable.
Or if you have a 5V power supply, try using that to power it.
Could be bad MCU, or could be whatever the MCU is trying to drive is shorted, causing increased consumption.

[BobLab]

"Heats up", but we don't know how much and if its an issue.

If your analog multimeter can measure current you can measure how much current the MCU is drawing and see if its reasonable.
Or if you have a 5V power supply, try using that to power it.
Could be bad MCU, or could be whatever the MCU is trying to drive is shorted, causing increased consumption.

Heats up a lot, I can't handle my finger there..Unfortunately the multimeter doesn't measure current, I've tried supply it with a external 5v power supply and the MCU heats up either, I'm trying to guess what peripheral must be shorted but without the schematics complicate things

[BobLab]

well, I powered the MCU on a protobord to make sure if wasn't any peripheral shorted, but the MCU still heating a lot, Is the MCU bad, or maybe the voltage regulator is bad?? any guesses?

[ss78]

Unfortunately dead mcu

[BobLab]

thanks for you reply anyway!