I have a Lenovo Thinkpad E420 and I have the following problem, let's see if someone can help me or help me, thank you

[german_20ar]

The Notebook turns on correctly as long as it has not been used for the last 20 Minutes. While it is on everything works correctly, but if I turn it off and want to turn it on again it does not turn on. I have to wait more or less 20 minutes and then it turns on again. Does anyone know where to start checking to see where the problem is? Thank you so much!

Espa

[mon2]

Could it be a MDM lock?

[mcplslg123]

Mention mb markings and link schematic,if already posted in this forum.
To me it seems like a thermal issue or a dying SOC.