Question about Onkyo TX-DS787 Receiver

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I cannot find the internal backup battery.

Hi there, I have read a similar problem posted by Bugsey but i have checked the boards with the fuses but still cannot locate the internal battery, any ideas thoughts. Does anyone know what type of battery i am looking for size shape etc. Thanks again.

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Re: I cannot find the internal backup battery.

I ran into the same issue with my Onkyo 787 receiver that the internal settings would get reset after a short power off. Getting all settings entered again (preferences, speaker distances, volumes, stations, etc.) is a real pain. Good news is that Onkyo DOES have a battery (actually a capacitor) to store the settings and that capacitor can go bad. Another good news is that replacement is quite easy.
The settings are preserved by a 5.5V 0.1F capacitor. Digikey sells it for around $1.50, you may choose a higher capacitance, as 0.3F if you're replacing it. I didn't want to wait for the part, so I decided to replace with something I had around from an old power supply. I used 10V 1000uF capacitor as a replacement and it works fine. Yes, it is 100x less in capacitance, but preserving setting for a short time is better than not preserving them at all. Settings survived a couple of days disconnect and I haven't tried leaving the receiver off for any longer yet.
Here's how you can find it: it's on the main horizontal board, on the same side where the volume control is. It's small, looks like a watch battery turned on the edge. Mine was in a blue shrink wrap. I cut off the leads next to the battery and left the wires sticking out of the PCB. There's plenty of room to put any capacitor.

Posted on Sep 29, 2011

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Re: I cannot find the internal backup battery.

I believe it is c906 on the Harmon Kardon 500 series receiver's "Tuner/Front Panel board". It is a .1F (note the lack of a 'u' in front of that F) 5.5v capacitor that feeds into the 5v power of the main chip.

Posted on Jan 06, 2013

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Re: I cannot find the internal backup battery.

Hi Craw,

Did you find the battery pack? If so where did you get replacements. I'm about to change mine out.


Posted on Sep 20, 2008

Re: I cannot find the internal backup battery.

On a TX-DS787 receiver there are no backup batteries for memory preservation.
There is a chip, probably a c-mos chip on the circuit board.
Mine erases memory during lightning storms.
Easiest way to fix is write down all your settings and reprogram when it goes dead.

Posted on Sep 29, 2008

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