Re: Complicated Napco MA2600 Internals Issue

["Jim" <alarminex@xxxxxxx>]

On Mar 1, 10:12=EF=BF=BDpm, "Katie Wasserman" <katie10...@xxxxxxxxx> wrote:
> Russ, Thanks for the suggestion and ARRL pointer but rewiring isn't an
> easy option.
>
> But I did try GQC's idea of using bypass capacitors on all the lines
> and that made a huge different, especially on the keypad lines, noise
> dropped by almost 15db. =A0All of the noise is/was coming from the alarm
> wiring, running running on the battery alone gives the same noise
> level, so the AC line choke wasn't needed.
>
> Jim, your idea of running off the battery power feed only doesn't
> work. =A0The system needs the AC power to start up or it triggers the
> alarm, there seems to be no way around this. =A0Putting in a fake
> battery using a capacitor discharging through a diode and charging
> through a parallel resistor didn't work either. =A0The system =A0does a 1
> second test using the battery about 1 minute after AC startup, that's
> how it determines if the battery is good. =A0After that point it seems
> to do a battery check each time the system is armed. So you really do
> need to have a real battery in there (or a giant capacitor) to make
> this alarm function.
>
> Thanks to everyone for you help on this.
>
> 73,
> Kaite (k1kdx actually k1kdx/ae)
>
Oh, and by the way, you didn't say whether you used and actual 12VDC
*Power supply* on the battery leads.  Using a makeshift rectifier
isn't the same thing as a regulated power 12VDC power supply. A fixed
12VDC power supply, I'm pretty sure, would fool the "battery check"
sequence. The panel just wants to know that there is 12VDC there. A
half wave rectifier or a charged capacitor is likely not going to
work. After addressing supplying a sufficent battery source,  it would
simply be a matter of applying AC first, which my previous post may
allow you to do.