Yamaha R-N602: no display/no audio
Yamaha R-N602: no display/no audio, power relay drops out after startup — extensive troubleshooting done
I have an R-N602 that powers into standby but won't complete startup. No display and no audio. Normally RY541 pulls in during startup, but the receiver shuts down after a few seconds.
I've got the service manual and have traced the PSU/protection circuitry. 5.5 V and 3.3 V standby rails are good. Transformer secondaries are present. DC_PRT is ~1.6 V, I_PRT 0 V. The LM19 heatsink sensor circuit has 3.3 V VCC and approximately 1.6 V PRT.
Interesting behaviour: disconnecting CB207 (the higher-voltage transformer secondary feeding the ±B amplifier supply) allows much more of the receiver to operate; the Speaker A/B relays can be operated, and the low-voltage supplies come up. Connecting CB207 causes the original startup failure.
Has anyone seen an R-N602 with this particular behaviour, or knows what protection condition would cause RY541 to drop out?
Questa è una buona domanda?
