Pioneer DT-400 MOD

[Mrcoolest123]

Hey guys. I have been rearranging my components a lot lately for cosmetic reasons and had to unplug my timer various times. I got a pioneer DT-400 for a nice bargain and the little thing has been part of my hifi system ever since. I love the machine, but having to reset the clock every time it's unplugged is really annoying, so I decided to try to fix it.

I read online that it is possible to stick a battery on the circuit to power it on for a short period of time while the timer is unplugged. Is it really possible to do it? Has anyone here done it and care to share some info on how to do it?

 

[markthefixer]

Don't believe everything you hear online.
And would you want to risk that irreplaceable LSI chip by essentially dropping it's power inputs dedicated to the constant running of the display?

An integral part of it's function, those display electronics....
Absent a datasheet that explains what it will and won't tolerate I wouldn't even try. TOO great a risk.

Stick the thing on a good UPS ("sinewave"?) and let the UPS keep it running.

 

[QSilver]

I've thought about the same thing however one point stops the idea in its tracks. The LSI samples the line frequency and uses that to drive its clock. Sure, if you unplug it and give it a battery it won't forget the time. But there's no line frequency anymore so you've essentially stopped the chip and the time.

Plug it back on and at best, time will have been paused. At worst, the absence of a clock pulse will have confused the lsi and you'll have to reset the power to it anyway. Setting the clock to 00:00.

In essence, it's simplicity is its biggest boon, with the slight con of no backup supply.

Still though, it's not too bad to set it back up again.

 

[redk9258]

The clocks that featured battery backup would use a crystal to generate 60Hz (or 50Hz). I've noticed on a clock that we used to have would gain time like crazy after a power outage. I have a Heathkit clock that I built in 1980 still in use. There's a guy that hacked it (I really hate calling it a hack) by adding a GPS and micro-controller to sync the time every night at midnight. It would also reset the time and alarm after a power failure. This is done in a way that is totally reversible and uses the original IC!