Hi @munchine ,
Has the clock/radio got backup batteries installed at all?
Here’s a link that shows where they’re located.
If so, disconnect the power from the device then remove the batteries.
After they’ve been removed, turn on the device for about 10 seconds and then turn it off again. This is just to dissipate any residual charge left in the device that may be holding any corrupted settings that may be preventing a normal operation.
Then reconnect the power to the device and see if it is now working etc. You can leave the batteries out at this stage as they are only there to maintain the settings in the event of a power failure. Also check if they may need replacing by measuring their voltage with a digital multimeter (if you have one) or if you think that they’ve been there for a long time.