Hi Everybody .

i got a AVR 171S for free yesterday , "same" symptom as you describe . Standby light is on , when i power it on , white light for aprox 10 sec, no text in display and then back to orange.
Put it straight on my bench and popped the hood , a strange hissing sound from the SMPS , started meassuring the voltage lines and soon found out 12 V + was missing .
Regulator IC97 (7812A ) ok , but the smoothing capacitor C 933 was all dried out . Replaced cap , unit is up and trunning :-)

Hope this helps someone :-)...