Pioneer VSX-LX51

RS232

Member
2006-01-17 1:49 am
Swindon
Hi everybody
Here to ask for a bit of help and advice regarding this 7.1 home cinema...
Problem:
Completely dead apart from blinking blue LED at the centre of the amp (HDMI 1/HGMI 2) and doesn't wake up after reset procedure.
Traced aux (stand by) voltage all the way to the main controller on the front panel and found to be correct including the signal from the "on" button.
After much head scratching and looking at the service manual I found that the "Wake Up" voltage from the aux power supply is low but not sure if it is (are) my voltmeters at fault.
Can someone help a depressed member before I scrap the thing....
Regards

PS: Yes I disconnected the flat cable and the voltage didn't change
 

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rayma

Member
2011-04-29 8:37 pm
If the two series parts are good, then it must be be of the three shunt parts instead,
or a fault on the pcb. First look at the pcb carefully. If that is ok, the capacitor would be the least likely.
So just measure the resistor. If that seems ok, then replace the Zener.
 

rayma

Member
2011-04-29 8:37 pm
It appears that the rectifier does not make DC, but a pulsating positive AC half sine
that is clamped by the Zener diode. If possible use a scope to check this after the 3.3k resistor.
There should be 8mS wide positive pulses, with 8mS of 0V in between them.

The amplitude of the pulses is the Zener voltage. 5.1 volts. The meter will read an average of this,
which is around 2.5V. Maybe there is no fault there after all.
 
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