Faulty Satellie Receiver?

I have an Amstrad DRX280 which had a faulty power supply. I hve now repaired this and all PSU putput voltages are ok. However when powered its goes thu the 5min delay then indicator goes green when pressed but error message on TV screen says "no satellite signal." As I know dish is ok( works with my own digibox) assume could be Rx front end any tips