Hi, everyone!
I am trying to fix an old yamaha p95 keyboard. 12 V doesn't arrive to regulator Ic401 nor ic402. 12V arrive to transistor Tr401 (emiter and base). 0V in the collector. Nothing changes pressing the switch. Led is of? Don't know what check. I would greatly appreciate any help to diagnose. Thanks!

 

Hi, everyone!
I am trying to fix an old yamaha p95 keyboard. 12 V doesn't arrive to regulator Ic401 nor ic402. 12V arrive to transistor Tr401 (emiter and base). 0V in the collector. Nothing changes pressing the switch. Led is of? Don't know what check. I would greatly appreciate any help to diagnose. Thanks!

 

Power source is giving 18V. Probably this caused some damage.

 

Hi! I bypassed transistor TR401 and the keyboard works. This was thanks to Mrchips explanation on a previous thread. So, thanks a lot Mrchips. Still don’t know why the switch doesn’t works but I can leave without it, I suppose.