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Old 01-08-2018, 11:01 PM   #1
benja1475
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Default YAMAHA RX-V775 Strange Problem

Hi... Good day to all and Happy New Year... I have a Yamaha RX-V775 and I have some strange problem, I update it to the latest version (1.93) via Internet. I notice some strange behavior with my unit after the update. First, I notice that the unit will not remember his last mode (e.g. if you turn off the AVR while in radio mode, by the time you turn it ON again will display that he is in radio mode) but now it won't, it will always be in TV mode. Second, it will cycle Tone Control Setting (bass, trebble) by it's own, and sometimes sound is cut-off (no sound) but the unit is still ON and it's not responsive, you can't control the AVR. I notice that the unit is not responsive if theirs no sound, but still the unit is ON and in the LCD display Tone Control setting cycle itself. It happen in random, Tone Control Setting cycle by itself then sound is cut off, sometimes Tone Control Setting cycles itself but sound is ok. The most strange thing I notice is... you can now turn ON/OFF the unit by pressing Tone Control button in the front panel and sometimes pressing the MAIN power switch button will not power the unit, but pressing the Tone Control button will turn it ON without miss, and also very strange that while the unit is ON, you can cycle the Tone Control Setting by pressing the MAIN power switch button (main power switch is suppose to be just to turn ON/OFF the unit... hhmmmmm). I reset the AVR to factory setting, but worse thing happen, standby led will not light, but you can still turn ON/OFF the unit by either MAIN switch or the Tone Control button, and more worse issssssss... any of the buttons except Tone Control (which is now the power key) will cycle the Tone Control Settings. So I decided to download a new copy of the firmware (v1.93) from yamaha website and re-flash the unit via USB, because maybe I think the update via internet is not doing good (but I think it's done successfully because I still use the unit for several days until I notice the first symptom, "not remember the previous mode") but still the problem is the same. Any help is very much appreciated... thank you

Last edited by benja1475; 01-08-2018 at 11:02 PM..
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Old 01-09-2018, 09:45 PM   #2
Longbow
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Default Re: YAMAHA RX-V775 Strange Problem

After flashing the firmware you should get a message saying that the flash is successful. If so, you don't have a firmware problem and it won't be fixed by doing another update. First, do the factory reset (somewhere in the manual usually). Second, I would start looking for water damage or some reason that the display/front panel button micro isn't working. That might appear as one of the button scan lines missing (shorted, open). Does the unit behave badly with the remote AND the front panel equally?

Also try this: put the remote control in a drawer, and at the same time place some black tape over the remote sensor window. The remote might be transmitting continuously, or florescent lighting may be falsely triggering the unit. Just a thought.
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Old 01-10-2018, 06:33 AM   #3
benja1475
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Default Re: YAMAHA RX-V775 Strange Problem

Thank you for your reply, I decided to open the unit because I notice some trace of mice urine in the AVR top cover... unfortunately some of it went through the air vent and to digital board, IC83, IC921 and it's surrounding components are wet, not much but i think its enough to cause some problem. I clean it with denatured alcohol and after blow drying for several minutes... after an hour i test the unit, its thesame.
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Old 01-12-2018, 09:02 AM   #4
Longbow
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Default Re: YAMAHA RX-V775 Strange Problem

That figures. That's why the symptoms always change from day to day. There is no way to fix it, unless you can get a spare board from another unit.
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