Conion Burglar Alarm help.

[the_hun]

Ok. So when I first got my conion c100ff the burglar alarm. Worked fine, while there was a ton of other issues with the box which I have fixed and gone through. Now however, the only thing not working correctly is the burglar alarm... I press the button, walk away for a couple of minutes and nothing happens when I come back.
Now if I start to slowly push the alarm button in and out and fiddle with it sometimes I hear a faint alarm sound for a split second.. What could this be? I have cleaned my pots and switches with deoxit and again the alarm worked when I first got the unit.. Now 2 weeks later nothing

 

[Transistorized]

Hearing the faint alarm sound for a moment only while jiggling the power switch leads me to believe that the power switch may be suspect. It is very rare that the sensor goes bad on these. I am willing to put my bet on the power selector switch. I am not sure which method you have used to arm the alarm however try it both ways.

Method 1: Turn the radio on and leave it on. Then while the radio is playing press the sensor power button. What should happen is you should hear the faint alarm sound until the radio powers down. The radio should stop playing, the power light should go out and only the sensor power light should illuminate. Leave the main power button depressed. At that point after 1 minute of sitting the alarm doesn't go off by walking in front of it you can try to grab a flashlight and shine that in the sensor between the LEDs to see if possibly the sensor is failing.

Method 2: The box main power switch is off and switch only the sensor power button. Wait 1 minute then test.

The reason for testing it both ways is to see if the switch seems to be functioning correctly. I have seen some where the alarm goes off when the radio was on and left on while setting the alarm where it didn't the other way around. Always led back to the switch being the issue in those cases.

It would be hard to diagnose this over a forum however my bet is a loose, faulty connection either in the power switch or its connector. Since it was working before that is my guess. Also some switches (rare but it happens) do not respond well to deoxit so if deoxit was used on the power switches it could've inadvertently dislodged some old grease or crud between two contacts internally and caused this issue as well. In this case taking the selector switch apart and cleaning may be required.

 

[the_hun]

Ok so I did try both of your methods for testing. And I get the exact same result both ways. After letting it sit a couple of minutes I go in front of the unit and nothing happens.. Now if I depress the sensor button slightly, and slowly press it back in before it actually clicks. The alarm goes off loud and clear as long as I continue to hold it in the one position. But if I let go it shuts off. I also completely removed and desoldered the sensor switch to open it up and it looked totally fine.

 

[caution]

Did you clean the contacts or use a cleaner? If you're certain the switch is A-OK and the alarm circuit is working when you hold the switch a certain amount, then you might have to do some sleuthing, maybe on the power switch board. I've clipped that area of the schematic with some notes.

A note about S2002-3: Although S2002-2 cuts power from the input to the voltage regulator at Q204/D202, which powers most everything in the box, it still leaves the deck 1 motor attached to it, so S2002-3 may sever this connection to avoid motor energy from leaching into it, if say someone were to press the alarm button while deck 1 is running.

Node E connects the power pins of the amp chips to a switch in the alarm circuit.
Node F provides power to the alarm circuit, but only when the alarm is enabled.
Node G taps into the left channel audio path. The right channel's tap is shown going to pin 2 of the amp.
Node N provides power to the alarm circuit, but only when the alarm is disabled. Once enabled, S2002-2 redirects power from node N to F. Powering the alarm circuit while not in use may help lock down its output circuits.

 

[the_hun]

Thanks for the post. We'll it turns out the LA6324 chip is faulty. It's not supplying correct voltage. The 10th pin seems to be dead.
On a side note at least I was able to get my 5k vr002 pot changed out and I have the stereo light again!