Yamaha MT100 II crackling noises when recording

[aerogramma]

Hello everyone,
my old MT100 II has developed a n issue, when recording I sometimes get loud crackling and pop noises, it seems to me that is more likely when approaching red levels on the meters. Those noise are then printed on tape.

I'm running a prerecorded song from my PC through my audio interface into the tape deck

Any suggestion on where I should start to look for troubleshooting?

Many thanks

 

[sweetbeats]

Hi. Does this also happen when you are listening to audio at an input, or does it only happen when you are monitoring tape playback?