Hi folks,
I have problems with my Marantz SR7000. I really need your help to fix this.
I have this marantz for years now and has been setup for 5.1 home theater system in my living room. It was working nicely until last december.
I disconnected the power source before I went for vacation for about 3 weeks. And when I returned, the unit wont turned on while stanby led is on (red light comes out).
I opened the case and checked the unit and there is no sign of burn or damage. So, I clean the unit and use the hair dryer to get rid of humidity that may have created a problem.
After cleaning and drying, the problem still exist, the remote controller still wont make the power relay to click. I understand that the click of the relay will allow power to main transformer.
Further, I observe one capacitor (470uF/35V) is swelling. It was CB66 in the -30V rail (Vkk). The schematic shows -30V, but measurement with multimeter shows -60V. (I am confused by capacitor CB63 placed in series to 22.3V AC supply from transformer).
The service manual suggest to check this Vkk and FL. The FL, which is 5.1VAC from the transformer is OK. But Vkk is -60V ! And this has drive me crazy, since it supplied from 22.3 VAC through 100uF Capacitor.
I have checked all the capacitor and managed to do this:
1. Replace all suspected caps with new one.
2. Replace 6V regulator IC, 7806 to get 5V supply
3. Replace QB52 transistor, I was suspected this is the culprit. But it is not.
4. Pull out the power relay and check it. It is still good.
5. Replaced 8.2V zener diode at FL rails.
And still not working.
Additional info,
1. This power supply board PB54 is intended to provide 5V, Vkk and Fl to front panel. The Vkk is supplying pulldown voltage (?) VEE to FL driver IC which is mpd16311.
2. This board also provide 5V to "mother board" at the bottom of casing. Whenever I disconect the supply to motherboard, the power relay is vibrating.
Attached is the schematic. Any help or opinion is appreciated.
Regards,
Javen
I have problems with my Marantz SR7000. I really need your help to fix this.
I have this marantz for years now and has been setup for 5.1 home theater system in my living room. It was working nicely until last december.
I disconnected the power source before I went for vacation for about 3 weeks. And when I returned, the unit wont turned on while stanby led is on (red light comes out).
I opened the case and checked the unit and there is no sign of burn or damage. So, I clean the unit and use the hair dryer to get rid of humidity that may have created a problem.
After cleaning and drying, the problem still exist, the remote controller still wont make the power relay to click. I understand that the click of the relay will allow power to main transformer.
Further, I observe one capacitor (470uF/35V) is swelling. It was CB66 in the -30V rail (Vkk). The schematic shows -30V, but measurement with multimeter shows -60V. (I am confused by capacitor CB63 placed in series to 22.3V AC supply from transformer).
The service manual suggest to check this Vkk and FL. The FL, which is 5.1VAC from the transformer is OK. But Vkk is -60V ! And this has drive me crazy, since it supplied from 22.3 VAC through 100uF Capacitor.
I have checked all the capacitor and managed to do this:
1. Replace all suspected caps with new one.
2. Replace 6V regulator IC, 7806 to get 5V supply
3. Replace QB52 transistor, I was suspected this is the culprit. But it is not.
4. Pull out the power relay and check it. It is still good.
5. Replaced 8.2V zener diode at FL rails.
And still not working.
Additional info,
1. This power supply board PB54 is intended to provide 5V, Vkk and Fl to front panel. The Vkk is supplying pulldown voltage (?) VEE to FL driver IC which is mpd16311.
2. This board also provide 5V to "mother board" at the bottom of casing. Whenever I disconect the supply to motherboard, the power relay is vibrating.
Attached is the schematic. Any help or opinion is appreciated.
Regards,
Javen
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