Time to troubleshoot FBII XL2T

[SpaceGuy65]

The house we bought came with two separate identical systems (panel code SAXL2T-2) one for upstairs and one for the basement suite. Basement suite installation on has two keypads so we can sit it off from upstairs. Upstairs installation has only one keypad.

The problem

The basement suite keypads don't "fully come to life". You can tell there's power as there's some level of backlighting to them but the buttons/indicator lights don't light up.

I've replaced the transformer and battery and still no difference.

I've replaced both user-replaceable fuses (1A and 3A). The 4A non-user-replaceable one is blown, but it is blown on both panels... so that is not the culprit. It just means the battery doesn't get charged and I have to program the AC/LB Sounder to not be audible for now until I solder in a new fuse.

The upstairs installation works fine.

But that second panel has me stumped. I'm out of ideas of what to try next. Any suggestions?

 

[Delta Prime]

Welcome to Maker Pro.
If I may; @ChosunOne Help!!

Do you have the manual?

Fbii XL-2T Manuals

Fbii XL-2T Pdf User Manuals. View online or download Fbii XL-2T User Manual

www.manualslib.com

In the meantime.

 

[SpaceGuy65]

Thanks for this
Yes I do have the manual which has some some help

I have measured my AC voltage in connection at screws 24-25 and am at roughly 14.20 - 14.30 on both panels

My DC voltage however is at 13.75 on the working panel and only 11.50 on the panel that is defective

Could this be the problem? And if so any idea where to look for the fault?

M

 

[SpaceGuy65]

Thanks for this
Yes I do have the manual which has some some help

I have measured my AC voltage in connection at screws 24-25 and am at roughly 14.20 - 14.30 on both panels

My DC voltage however is at 13.75 on the working panel and only 11.50 on the panel that is defective

Could this be the problem? And if so any idea where to look for the fault?

 

[SpaceGuy65]

Same numbers on the regulated power at 21 and 23

 

[SpaceGuy65]

Thanks for this
Yes I do have the manual which has some some help

I have measured my AC voltage in connection at screws 24-25 and am at roughly 14.20 - 14.30 on both panels

My DC voltage however is at 13.75 on the working panel and only 11.50 on the panel that is defective

Could this be the problem? And if so any idea where to look for the fault?

That's measured at the panel connections, 12 and 15

 

[ChosunOne]

First of all, kudos for keeping your systems going for the last 30-or-so (?) years . I apologize for my delay in responding: I haven't worked on one of these for almost that long--they were good panels--and I needed to look over the Installer's Manual to re-familiarize myself.

The symptoms you describe sound a lot like your errant panel is suffering from low voltage--either because (1) it isn't getting enough juice from the 12VAC transformer, or (2) it's losing its power in the panel itself somewhere (least likely statistically, but not uncommon), or (3) the panel voltage is being drawn down at one of the nominal 12VDC outputs (Terminals 12 & 15 and (less likely) Terminals 16 & 21).

Your transformer is reading nominal, so I'm going to overlook it as a possible trouble source; but I may come back later.

Before I'd condemn the panel, I'd try disconnecting everything from T-15 and T-21, the positive sides of the aux outputs. CAUTION: Tape the ends of the wires you've disconnected so they don't touch anything: Those are live 12VDC wires that can blow the panel for sure if they hit the wrong thing.
Also, you might want to disconnect the siren from T-22 while you're working, in case the panel wants to get noisy.


If T-15 & T-12 read nominal (~13-14 VDC) with wires off of T-15, then your problem is probably some panel-powered peripheral device drawing down the voltage. Add the wires back, one at a time, until the voltage drops again; and you'll have your culprit. Same with T-16 & T-21.
If you find the trouble is in a peripheral device (keypad, motion sensor, glassbreak sensor, etc...), post back and we'll go from there. If the voltage is still low twix T13 & T15, then your panel is shot and there's not a lot I can do for you but recommend a replacement.

We didn't repair malfunctioning devices in the field, so if you manage to fix yours, more power to you; but I'd have to have the panel on my bench even to think about trying that.

 

[SpaceGuy65]

Thanks for the detailed post.
I just came back from work travel and started looking at this again.

It does look like the panel itself is the problem. I have ordered a replacement in eBay, hopefully this week fix it.

I'll post the result when it arrives