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Car Stereo Memory Loss

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  • Power Supplies
  • Memory
  • Audio
Last response: in Home Audio
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June 6, 2011 10:13:21 PM

I know this isn't exactly "home audio" but it's pretty damn close and figured this was the best suited forum.

Stereo I bought: http://www.amazon.com/Sony-CDXM10-Marine-Receiver-Slot/...

It doesn't really matter concerning the question but I know people will ask. This is being installed in a 83 Cj7.


Ok, now the problem is the stereo loses its memory every time the ignition is off. The stereo will run fine when the key is on, but every time it starts up everything is reset. I wired the stereo myself. Aside from the speaker wires there are three wire required to run the stereo properly. A ground, constant power supply (for memory), and a key on power supply. I have a good ground. Both power supply cables are wired into the fuse box. Direct wire in, no fuse. I have the power lead for the memory tied into the "clock" slot in the fuse box which provides a adequate constant power supply. I have stuck a testing probe in the slot and played with the ignition. This is always powered. I tested the wire at the end of the plastic bracket that clips into the back of the stereo as well and confirmed it to be hot there as well.

From my reasoning, the stereo should not be resetting the memory. I consulted with my father about it and he agrees and cannot figure out why it is not working.

Anyone know the problem?

More about : car stereo memory loss

June 7, 2011 1:39:49 AM

there are two power wires, one dedicated to battery, one for ignition. the battery wire maintains the memory, the ignition is for higher power.
you should see this in the installation manual. if you do not have the manual download it from the manufacturer or vendor website.
or the unit is defective.
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June 7, 2011 2:42:51 AM

well if your constant power wire is actually constant.. that leads only two rational thoughts.
1. the voltage from the constant power wire isnt high enough to keep the memory 'charged'
2. the memory inside the radio is bad.

it is good that you have tested for constant power.. but now you need to check the voltage to finalize your troubleshooting.
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June 13, 2011 5:40:51 PM

I feel a little stupid for this, but it doesn't make sense to me. I was looking at the wiring diagram again and it turns out I had the wires mixed up. There's a black wire for ground, yellow wire same gauge then a red wire that is smaller than those two. It turns out the the lower gauge wire is for the main power and the high gauge wire is used for the lower voltage memory. Doesn't make any sense to me but now It works.
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June 13, 2011 7:37:27 PM

it makes sense to me.. the main power can come from the yellow wire, the red wire, or both.

think about it like this.. if you wanted to suck up some water because you were thirsty, you wouldnt want the water to go into a second straw of smaller size before it gets to your mouth.
that means less water and more time before you can swallow.. not good for being thirsty.


if you are really confused.. an amplifier has a huge wire for positive and a huge wire for negative, then a tiny wire for the remote to turn it on and off.
the radio is basically doing the same thing with the wire from the ignition.

anyways.. dont feel too bad about it, people get a thought into the back of their mind (or they get interupted by someone else) and the mistakes happen.
as long as you were paying close attention to the power wires to not mix up negative with positive (or negative/positive with a speaker wire) that is the highest priority to prevent breaking the radio.
you didnt break anything, so you should be good to go :) 
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October 18, 2012 5:16:57 PM

Our problem is a bit different -- mainly the presets are remembered when the ignition is off, so it doesn't seem to be a wrong connection. But occasionally the memory does reset itself (without the battery being disconnected). I think this might be because when the engine is started the voltage drops a lot, and occasionally it is low long enough for the memory circuits to fail. Is this possible? We've just got a new car and it might be better in this respect.
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