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Post by hiroshi976 on Jun 8, 2022 13:21:12 GMT -5
I have an Onkyo 608, already repaired here, (thanks to the advice of Tjmotter.) Now have other problems. A few days ago when turned off, the subwoofer speaker started making noise occasionally (similar noise buzzrr!). The next day, you could hear the typical noises of the click of the relay, of the power supply. After several days, it does not turn on (led rest fixed on HDMI trought), when it turns on, it often does not turn off, it restarts by itself (reboot). Other times, if I turn it off, all the LEDs go out. From today, it does not turn on anymore, if I press the power button, the LED flashes, always, until I release the power button. I replaced, again, the Q181, I checked in the power supply C922, C930, D925, C902, and the 47 Ohm resistor R921 (46.7) everything is perfect, or at least it seems. What can I check? What does the error mean, flashing of the led? this amp is perfect for me, i wish i could fix it. Thanks for any advice and sorry for my english.
Hiro!
edit: I have attached the schematics, sorry if I didn't do it before.
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Post by hiroshi976 on Jun 10, 2022 16:04:01 GMT -5
Hi
I completed the tests of Power supply, disconnecting the JL901 connector from the MPU, and checked without the MPU card. Checking all pins of JL901, I detect 11.50v, on PIN1, PIN2 and PIN4, on PIN5 I have 6.50V. The service manual says that on the PIN2 I must have 10V and on the PIN4 12V. Could this be the cause?
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Post by hiroshi976 on Jun 14, 2022 13:16:01 GMT -5
Now I often find the STANDBY led turned off. These days I have been testing other parts - Q702 and Q703 voltage regulators, they are ok. Q702 5.6V in IN and 3.3V OUT. Q703 10V in IN and 5.6V OUT. I have the 3.3v on C508. R650 is ok. What else can I check? I notice that I have "dancer voltage" in the pins of JL901 if I unplug and plug in the electrical plug. They range from 10.5V to 12.6V. What would be the correct voltage of the 5 pins at standby amp? I noticed that after the R181 I don't detect the 12V.
JL901
PIN1 MPOWERED: 10.40V
PIN2 +10VS: 10.40V
PIN3 GND:
PIN4 12V: 10.40V
PIN5 P.OFF : 4.50V
after unplug/plug come up to (random)
PIN1 MPOWERED: 12.60V
PIN2 +10VS: 10.20V
PIN3 GND:
PIN4 12V: 12.60V
PIN5 P.OFF : 4.50V
thank you for any advice.
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nodols
Junior Member
Posts: 75
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Post by nodols on Jun 14, 2022 19:02:55 GMT -5
Just exploring some possibilities here, have you tested for leaky caps?
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Post by hiroshi976 on Jun 15, 2022 11:02:37 GMT -5
Just exploring some possibilities here, have you tested for leaky caps? Thanks a lot for the answer!  yesterday it did not turn on. Then, after some time, the red standby led came on again and I was able to turn it on. I checked, out of the circuit, the diodes D182 and D183 and the resistor R181. All perfect! I have verified that in the area after R181 and before D182 I have the 12V when the amplifier is on, but in the cathode of D182 I do not have the 10V indicated in the manual, but about 12.50V, I detect the 10V in standby. I also checked the presence of 3.3v on the MPU and I find 3.3 volt in C508 (pin34/Q701), I checked many resistors and capacitor around Q701, all ok!
I noticed that when the amplifier (succeeds) switched ON I had these measurements on the JL901 connector JL901 in standby (red led on) PIN1 MPOWERED: 12.90V PIN2 + 10VS: 10.50V PIN3 GND: 0 PIN4 12V: 12.90V PIN5 P.OFF: 4.90V
after press ON (receiver active,display operative)
PIN1 MPOWERED: 80 mV PIN2 + 10VS: 12.50V PIN3 GND: 0 PIN4 12V: 12.50V PIN5 P.OFF: 5.40V
now I have unplugged the electrical plug, at the next restart if he comes back dead again, I want to see what measures I detect on JL901, so I can make a comparison between dead measurements and operative measurements.
Can you recommend a total recap of the power supply? Last time I tested the power supply, I only checked the capacitance of the capacitors, and shorts, and checked the relay. Maybe the capacitors are really leaking. Maybe I suspected too much it was the fault of the relay, and instead it is a generic problem of power supply (??).
Thank you all! : D
Thanks for any advice
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Post by hiroshi976 on Jun 16, 2022 8:06:53 GMT -5
I checked, with everything connected. It is the subwoofer connection that is causing problems. If I turn on the 608, noises come from the sub (brrr) when press ON/Standby. After a few turns on and off, the amplifier dies! Standby led go off! Could it be a short in the PRE output for the subwoofer, or a short in the active subwoofer?
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Post by tjmotter on Jul 21, 2022 14:57:50 GMT -5
I would be suspicious of the mute circuit for the subwoofer. Specifically, check Q4107 and Q4117, I would also replace C4107.
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