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.
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. Pixonian
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.
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.
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Check for open Fuses first of all. Test the battery again on load not just with Multimeter. You can use a 10Kw potentiometer resistor or a 80W Car head lamp as the load on battery and see if the voltage still reads 11.8V for the first 30 second. If the Voltage drops rapidly and there are no open fuses, replace the battery. Alternatively contact a local technician for troubleshooting on the Board.
read the manual yet, or lost it> or?
most of these have 2 batteries
one that pops out one more that solders down.
guess which one retrains data.
finding parts for relics like this is not fun
what good is this thing besides, wall art?
why ask here at all, we are not HP , nor are there HP books here.
so ask here.
there are folks there that might remember so long ago
or even have old books laying about after all they are HP.
there be an internal fuse or reset button on or close to circuit board, you'll have to open it up to get at curcuit board, make sure you have power at wall receptical, cord isn't bad, unplug when you open it, be safe
internal failure possibly on power side, lower than 300A fault current so unit could not trip i/p protection and as fault was post ac section, continued to burn internally. it just broke no breakers tripped out so it kept drawing current until the fault burnt away.
maybe this is what happened, need to know a lot more info to change hypothisis
More often than not, it is the internal battery of the UPS that causes switching off. In some instances it may be that too many devices are attached and drawing power from the UPS. In rare instances, it is the electronics controller that is at fault.
1. Since checking the battery involves opening the unit, you may be better off seeking the services of a qualified professional (there are dangerous voltages inside the unit even when off);
2. Try removing some of the devices connected to the UPS and simply leave the PC itself connected to the UPS. All others may be plugged in to the mains;
3. Checking if it's the electronics would be similar to # 1.
Hope this be of some help/idea. Post back how things turn up or should you need further information.
Good luck and kind regards.
You have to first charge the backup battery, for charging insert a fully charged main battery into the MC906x. Then the backup battery will starts charging leave it there for one day. if that message is still coming then the problem is with the backup battery and u have to replce it