Okay so I got my hands on this nice Yamaha receiver. But it powers on then shuts off after a second. After fiddlind around with pressing all the button combinatons the receiver started workiong and worked excellently for a month, then the problem came back.The output relay doesn't click. But some standby voltages were wrong. I replaced all 2sc1740s and dta114 on the front board. The problem is still the same, but the dta114 voltage appears to be correct.
It seems to me that, either the replacement transistors are faulty (hopefully I will receive my transistor tester in the next few days), some capacitors (will receive the esr tester in the next few days) are faulty on the output board (since the reciever is 20 years old). Since the old soviet y 101 receivers had similar problems, and the cure was new capacitors. The front panel ceramic caps are ok. The standby board is working fine (checked in another similar receiver - rx v385, but the other receiver cannot be used for anything else, since the standby board is the only fitting part, some voltages could be checked, since they are quite similar in layout).
I will replace the 2sa933 transistor on the front panel, if I cannot find anything better to try. As a last resort I will just "disable" the protect circuitry and when the receiver dies then it will die in flames
.
It seems to me that, either the replacement transistors are faulty (hopefully I will receive my transistor tester in the next few days), some capacitors (will receive the esr tester in the next few days) are faulty on the output board (since the reciever is 20 years old). Since the old soviet y 101 receivers had similar problems, and the cure was new capacitors. The front panel ceramic caps are ok. The standby board is working fine (checked in another similar receiver - rx v385, but the other receiver cannot be used for anything else, since the standby board is the only fitting part, some voltages could be checked, since they are quite similar in layout).
I will replace the 2sa933 transistor on the front panel, if I cannot find anything better to try. As a last resort I will just "disable" the protect circuitry and when the receiver dies then it will die in flames
.
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