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Adding a battery to a digital tuner to retain the presets

A local second-hand store has a Kenwood KT-76 digital AM-FM tuner, for a fair price. it says it WORKS. I presently have an analog tuner which works fine, but I have been wanting to get a digital tuner for the presets. This tuner would probably be an ideal match for my Kenwood Basic C preamp (which is a great preamp).

Before buying it, I decided to look it up online. I did not find any bad reviews (of the little I could find), but I did find one which said that they lose their preset settings if the AC power is shut off for more than a short time.

This poses a problem, because I always shut down my entire stereo system with a power strip. I have many components and turning each one on or off individually would be a pain. And if I cant retain the settings, I may as well just stick with my analog tuner.

However, I assume the presets are similar to the bios in a computer. When the computer is unplugged, the internal coin cell battery keep the bios settings, time and date, etc.

Is there any way to rig up a battery (coin cell or AA, or other) to retain the settings, in this kind of tuner? I guess it depends on whether this is possible, and how difficult it is..... If it's not possible, I wont buy it.

Thanks

Reply to
oldschool
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Have you studied the schematic to determine how "presets" are retained when powered? Might be a good place to start >:-} ...Jim Thompson

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Reply to
Jim Thompson

Probably an easier solution would be to use a different outlet to power the tuner. Might something bad happen that can be prevented by you turning off the tuner?

From the free previews of the service manual I've seen online, enough information can probably be had for $4.99 to determine what needs to be connected where. it looks like IC4 is the one responsible for remembering the settings, but I haven't seen enough detail on that part to say how easy it would be to provide backup power to it.

Best case is it has terminals specifically intended to provide backup power to its SRAM and you just need to fit a battery parallell with an existing capacitor, (ideally the capacitor is charged no higher than 4.2V and you can fit a rechargable lithium battery

- probalbly it won't be that easy)

Worst case is it relies on remanence to remeber during outages and it needs its powersupply circuitry modified.

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Reply to
Jasen Betts

Cycling the power on his entire stack is not the greatest method or idea either. It is not that hard to push a few power buttons, and the gear must be old, so likely damned near pops the power strip breaker each time too. Anyway, I leave all my gear off, and then only turn on what I will use. So the CD player and turntable and etc stay off and only the amp and DVD player get power, if that is the case.

Anyway... sounds like a good place for a supercap. Or like you said... place certain devices on a different power circuit.

Reply to
Long Hair

This is not all old equipment. Older, yes, mostly 80s to 90s. But it's all commercial band type stage gear. From the speakers to the two power amps, which can output a total of 1100 watts RMS. There is a lot of gear connected to it. CD player, Studio tape machine, Preamp, Tuner, Equalizer, Compressor, Delay, Turntable, MP3 player, and a studio mic mixer, along with numerous guitar effects units. It's intended for both my stereo and for guitar, keyboard and other recording uses. I have a dedicated 20A outlet feeding it. Shutting all that stuff off is more than a few switches.

And some of the stuff is shut off most of the time anyhow, plus I usually turn on the power amps separately, but they are still on that power strip, so I can shut everything down all at once, and know it's all safely turned off.

About the only parts of this system that are not commercial gear is the Kenwood stereo preamp and a few input devices, including my present analog tuner.

I dont want stuff being left on, wasting electricity and also for lightning protection. So I have that heavy duty power strip to shut everything down at once. (Especially after I have a few cold ones, and want to hit the sack without fumbling around with 20 some switches).

Reply to
oldschool

Did you actually find a FREE download for the service manual / schematic? I spent a lot of time looking and cant find anything. If you did find one and recall the URL, please post it.

I suppose it wont be that easy. Yet I know there are a million clocks, and things like weather radios and scanners that have a battery backup.

Yet, I know there are too many things that dont. Especially car audio systems. Once the car battery is disconnected, everything has to be reset. (One reason I almost prefer an analog radio in a car).

Reply to
oldschool

You're right...

So a battery backup inside the case on that NVRAM circuit or a supercap. Likely a battery. Supercaps are only for temporary outages.

Reply to
Long Hair

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