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#1
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Denon - is there a back up battery?
I recently bought a Denon 'Personal Component System/AM-FM Stereo Receiver DRA-F100' unit from a charity shop - sold for spares or repair. Apart from a tuner issue the main fault is that after a while in standby mode it switches off completely from standby as though the mains has been switched off/a power cut.
Is there a back-up memory battery somewhere, I have tried leaving the unit powered up and switched on for at least 24 hours kidding myself that it will recharge the memory battery, if there is one? |
#2
Posted to rec.audio.tech
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Denon - is there a back up battery?
On Thu, 13 Feb 2014, Sainthunter wrote:
I recently bought a Denon 'Personal Component System/AM-FM Stereo Receiver DRA-F100' unit from a charity shop - sold for spares or repair. Apart from a tuner issue the main fault is that after a while in standby mode it switches off completely from standby as though the mains has been switched off/a power cut. Is there a back-up memory battery somewhere, I have tried leaving the unit powered up and switched on for at least 24 hours kidding myself that it will recharge the memory battery, if there is one? It would depend on the vintage. After a certain point, there were high value capacitors in very small packages that were used to keep memory alive. Don't leave it in standby, let it run for a decent amount of time at low volume and see if that solves the problem, which isn't really stated but would seem to be that the memory doesn't keep remembering. The weird thing is, a lot of recent equipment never turns off. The on/off switch controls the secondary of the power transformer (one reason being that it avoids bringing the 120VAC from the wall to the on/off switch and then back to the transformer), and so those can keep memory alive with a trickle of power from the power transformer. Michael |
#3
Posted to rec.audio.tech
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Denon - is there a back up battery?
The user manual makes no mention of a backup battery.
Dave M. |
#4
Posted to rec.audio.tech
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Denon - is there a back up battery?
On 13/02/2014 7:57 PM, Sainthunter wrote:
I recently bought a Denon 'Personal Component System/AM-FM Stereo Receiver DRA-F100' unit from a charity shop - sold for spares or repair. Apart from a tuner issue the main fault is that after a while in standby mode it switches off completely from standby as though the mains has been switched off/a power cut. Is there a back-up memory battery somewhere, I have tried leaving the unit powered up and switched on for at least 24 hours kidding myself that it will recharge the memory battery, if there is one? **I don't have the service manual for that model, but most machines of that vintage use a large, low leakage electrolytic cap of approximately 20,000uF @ 6.3Volts. It will likely be near the main microprocessor. -- Trevor Wilson www.rageaudio.com.au |
#5
Posted to rec.audio.tech
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Denon - is there a back up battery?
On 29/03/2014 10:32 AM, Trevor Wilson wrote:
On 13/02/2014 7:57 PM, Sainthunter wrote: I recently bought a Denon 'Personal Component System/AM-FM Stereo Receiver DRA-F100' unit from a charity shop - sold for spares or repair. Apart from a tuner issue the main fault is that after a while in standby mode it switches off completely from standby as though the mains has been switched off/a power cut. Is there a back-up memory battery somewhere, I have tried leaving the unit powered up and switched on for at least 24 hours kidding myself that it will recharge the memory battery, if there is one? **I don't have the service manual for that model, but most machines of that vintage use a large, low leakage electrolytic cap of approximately 20,000uF @ 6.3Volts. It will likely be near the main microprocessor. **BTW: By "large", I mean in capacity. The physical size is likely to be approximately 20 ~ 25mm high and 15mm in diameter.It may also use a 'supercap', which could be in the range of 0.1F ~ 1F @ 5.5 Volts, but I doubt it. -- Trevor Wilson www.rageaudio.com.au |
#6
Posted to rec.audio.tech
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Denon - is there a back up battery?
On Sat, 29 Mar 2014, Trevor Wilson wrote:
On 29/03/2014 10:32 AM, Trevor Wilson wrote: On 13/02/2014 7:57 PM, Sainthunter wrote: I recently bought a Denon 'Personal Component System/AM-FM Stereo Receiver DRA-F100' unit from a charity shop - sold for spares or repair. Apart from a tuner issue the main fault is that after a while in standby mode it switches off completely from standby as though the mains has been switched off/a power cut. Is there a back-up memory battery somewhere, I have tried leaving the unit powered up and switched on for at least 24 hours kidding myself that it will recharge the memory battery, if there is one? **I don't have the service manual for that model, but most machines of that vintage use a large, low leakage electrolytic cap of approximately 20,000uF @ 6.3Volts. It will likely be near the main microprocessor. **BTW: By "large", I mean in capacity. The physical size is likely to be approximately 20 ~ 25mm high and 15mm in diameter.It may also use a 'supercap', which could be in the range of 0.1F ~ 1F @ 5.5 Volts, but I doubt it. That's a good point. I remember the cartoons in hobby magazines about what a Farad capacitor would look like, usually the single unit delivered ont he back of a truck. If such large capacitors existed, they sure weren't at the hobby or consumer level forty years ago. I remember buying a 'computer grade" electrolytic, the size of a Coke can, 15,000uF at about 16V. Barely high enough voltage rating for my purposes, but it was what I could get surplus. Now you can get even higher capacitance electrolytics in a much smaller package. ANd yes, by physical size, you'd never grasp that those backup capacitors in more recent equipment had such large capacitance values. Michael |
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