Security & Fire Protection Systems/CADDX Ranger 8600E


QUESTION: I have a CADDX Ranger 8600E wired security system, new with the house in 1995. Recently, while having some drywall and painting work done, the alarm was tripped - perhaps by dust in the smoke detector from their work?  I wasn't at home at the time, they called me, and I had them trip off the breaker powering the system.  Battery is dead, so the alarm went away.  When I got home and energized the breaker, zones 1 and 2 door monitors won't clear.  I just use the security alarm for the beep when doors open plus the smoke alarms.  I don't know if the painters caused the lingering issue, but you gotta wonder.  Could the dead battery be causing the issue?  Zone 3 door monitor works OK, so I know the door chime function turns on and off OK, and the fire alarm zone works.  I tried twisting the wires together at the door sensors on zone 1 to rule out the sensors to no avail.  Any suggestions?

ANSWER: Hello Mik, and thanks for writing.

Painters wouldn't normally put two door sensors out of whack, but as you say, it's about the timing. And since you bypassed the sensors by twisting the wires together with no luck, you'll have to look elsewhere.

The battery is not the problem, although you should replace it so the fire alarm will work during a power failure.

I'd check to see whether there is any other protection on those zones besides the door sensors. Glass break detectors, perhaps? Look for any exposed splices or connections that have been painted over. Clean any of those connections that you find.

Another possibility is that the paint has caused a ground in the circuit. That's a long shot, but worth looking at. Any exposed wiring that's been painted over around a metal door frame.

Without being able to put a meter on the circuits, there's nothing more you can check.

I hope this helps, but I think it's likely you'll need a tech to inspect and troubleshoot the zones.

Best Regards,


---------- FOLLOW-UP ----------

QUESTION: Dave - thanks for the quick response. I don't believe there are any more sensors on either of those two zones. If there are, I can't find where they would be.  There are three zones, with two door sensors on each zone.  Two of those zones won't clear, the other one does clear. There are two motion detector zones that are both bypassed because of pets, and one fire zone.

I'm beginning to think the paint issue was a coincidence or somehow they messed with something more than the fire zone, though I don't see how they could have. They weren't painting anywhere near the door sensors, but I know they were pushing buttons on the keypad to try to stop the alarm horn.

I'm going to lift the wires off zone one, and then zone two, on Tuesday and check the resistance on those loops.  It appears I should see 330 ohms from the termination resistor on each loop.

Two questions: do you know what the resistance should read across the terminals 1-2, 2-3, and 4-5, on the PCB with the wires removed and the power off?  I guess I could check zone 3, the known good zone, to compare with one and two.  Also, do you know if the symptoms I am seeing are typical of an older CADDX system?

If I can get this working again, I'll pick up a new battery, too.

Thanks again, it's great of you to spend the time to help folks on issues like this.

CADDX 8600
CADDX 8600  
Hello again Mike.

I'm glad you have a meter in hand.

The end-of-line resistor is 3.3K, or 3,300 ohms. So, on a normal zone with no power from the control applied, you should read that amount. If you read infinity (no resistance), that's an open circuit, and if you read zero ohms, that's a short circuit. While you have the zone wires disconnected from the panel, also measure the resistance between the alarm zone and terminal 20 on the panel, which is the earth ground. You should read infinity there; if you measure resistance, there's a ground on the protective loop.

The symptoms you describe are common alarm circuit issues; they have nothing to do with the age or brand of the control panel.

By the way, I'm attaching an image of the hookup diagram for your panel.

I hope this helps!

Best Regards,


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Dave Neuweiler


The design and application of burglary and fire systems for homes and businesses. Helping alarm owners understand how their system works. Helping to troubleshoot false alarm problems. Questions about monitoring issues.


Over a quarter century in the industry. Experience in installation, service, and monitoring centers. Training manager for a national protective services company; director of education and training for a national trade organization for for alarm dealers.


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