Hi Jeevan.
First check your power supply and see that power gets into the radio.
check fuses if they are there.
Be carefull with the mains side of the transformer 220 / 230 Volts.
Secondary is probably around 6 to 12 Volts ac.
Then check the bridge rectifier and elco and you have dc on your supply rail.
Check the switches and work your way step by step through the recorder.
If the amplifier works you should be able to get some hum or scratching sound while operating the tape/radio switch, check the potentio meters for volume etc.
Check the little microswitches which drive the tape motor.
Check for loose connections, discoloured parts and possible smell of something burned out etc.
If it was a battery/mains tapedeck, maybe leakage from old batteries has corroded some terminations inside.
I hope some of these steps may help you on your way a little.