不得自行维修 英语怎么说

Shall not be self-maintenance

I have to maintain it myself
我不得不自行维修
he has to maintain it himself
他不得不自己维修

have to mend the bike

Can not be repaired on thier own.

Repairing by yourself is not allowed

The applliance, should only be serviced by qualified engineer.

婉转一些。要比说自行维修好些。