Home Theater Questions? Ask a Technician for Answers ASAP
the power led comes on and clicks in standby. when I push the power button the led flashes green and unit starts clicking. I want to do a component level repair on this. I have a service manual if you need it.
not much really. The original problem was no power. I found shorted and blown parts and replaced them. The unit powered up after. I then was told to check the idle current and forgot to set the volume to low so as soon as I turned the power on, there was smoke and then now clicking. Checked parts i replaced and they are all good. It has to be something in the power supply.
I found a transistor Q504FR on the pre amp board which is part number KSC1845F. It measured bad in and out of circuit .I was getting readings both ways and tested against a good one and it is probably defective. All of the output transistors measured good.
yes I measured R511FR and it is open, so I think I found the problem with the power relay clicking. I will order the parts and update you.
I also found R110FR and R111FR both open.
I tested all of them and they are good.
I replaced the parts and the unit still clicks.
Then it is still kicking in auto-protect mode due to another fault.
What are the voltages of pins 1 and 2 of connector CP502 of the Main Board please?
...and have you re-checkled all the output voltages of the power supply ?
I was able to get the voltages from the p/s, the 5,15 and -15v and they were all good. At CP502 the voltages jump around since the ps keeps going into protective mode. For some reason the display now stays on, the power LED is solid green and the clicking stopped, but when I try and take voltage readings they drop as soon as I touch my probe.
Yes I have an analog meter.
what will these tests check for. I also noticed that when testing voltages they jump around a even show a negative voltages even though the circuit i tested doesn't have negative voltages.
I posted a video on youtube so you can see what I am seeing with the receiver.
ok I am not getting anything consistent for either, voltage drops when I measure.
Here is another video
ok found something else. When I measured from chassis ground to the pre amp board, when I measured from chassis ground to ground, I got no resistance. I don't have any of the screws in place on the receiver, just sitting loose. When I connected chassis ground to a ground pin on the pre amp board, the power now stays on and I get all the voltages. Not sure what is missing for the ground to be gone.
Ok I got everything connected properly so I can do voltage tests now. It still keeps clicking.
Appreciate the update now and again later when able.
ok I found that if I turn the power on and don't have any outputs selected, the power stays on. Once I turn on speaker a or b, or surround, the power keeps turning off and on. On connector CP557, there is a DC protect, over protect that is normally 0v. When I turn on the output, the voltage jumps up to 0.7v,then to 0v.