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Originally Posted by darbyjudy
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What could have happened that the 12 volts will no longer work. Do I have to purchase a new Digital magic? Can you buy parts for them? I can continue using the 9 volt battery but it is a hassle to change when the battery goes dead. Any one with a little help.
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I haven't looked at the pc board in quite a while and don't remember what the 12 goes through before it gets to the circuitry. Usually devices used in an automotive environment have some voltage conditioning components to protect the circuitry from transients/spikes. I suspect that one of those components has failed or there is a bad solder joint.
You can try to get a friendly (as in free - maybe a ham radio operator or retired tech) technician to troubleshoot it.
Paying someone to do it will probably cost as much as a new board.
Since the circuit works on the 9 volt input you could do what I did. My unit was installed by the dealer and he did not run 12 volts to it. He chose the easier 9 volt battery route.
I got tired of replacing the battery every couple of months and made a simple voltage regulator that has a 9 volt output.
I got a LM7809 integrated circuit at Radio Shack, added a couple of capacitors, a 9 volt battery snap on connector, soldered it together on a small piece of perf board (also from Radio Shack), then mounted it with double sided tape on the inside wall of the display housing. Note that since the battery connector is intended to snap on a battery and not where a battery snaps on, the snap on connector red wire will go to the negative 9 volts from the regulator and the black wire will go to the positive 9 volt output.
I got 12 volts from the back of the Winegard amplifier wall plate and connected that to the regulator.
You can get a data sheet off the internet that has the circuit diagram and capacitor values.
Mine has been working great for several years with the regulator.
One thing to be aware of when using either a 9 volt battery or the 12 v supply is that the unit can sometimes get lost in the land of digital bytes and need to be reset by removing all power for 30 seconds or so. I have had to do that four times in the 7 years I have had it. Only once with the regulator circuit in place though.
As I recall I got a "ER" on the display when it had to be reset.