Blinking power LED

Fire Alarm Help
1

What does blinking power LED indicate on Siemens MXL fire alarm panel and how to reset it.
Regards

2

I went ahead and moved this to Fire Alarm Help.

According to the manual, a blinking power LED means the panel is running off of battery backup. Try checking the AC connections to the panel, the transformer, the AC wiring, and the breaker. The breaker may be tripped and that may be why you arenā€™t getting any AC power.

Hope this helps!

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3

Hello Robert,
Thanks for your prompt response.
AC input power is ON and if I dieconnect batteries panel remains functional. However there is one more trouble noticed on the display that reads ā€œAC Brownoutā€. Although input supply voltage is about 235VAC. What could be the reason for such a situation? What is the threshold level for system to generate AC BROWNOUT alarm?

Regards

4

Iā€™m assuming the primary AC voltage of your panel is 220-240 VAC, right?

The manual doesnā€™t give too much info on the subject unfortunately, it only says that for the AC BROWNOUT trouble that the AC voltage is ā€œbelow the brownout levelā€ without actually stating what it is. 235 seems pretty nominal so Iā€™m not sure why you would be getting that trouble.

Iā€™m going to go ahead and sit this one out as I am not a tech, and defer to another Siemens tech (we have a couple here), but in the meantimeā€¦

Keep in mind that you should only do this in accordance with your local codes, but if you cycle the main breaker to the panel (i.e. disconnect AC, then reconnect AC), does the panel go back to normal? The reason I say this is because sometimes the panel is receiving the proper voltage but doesnā€™t catch up with itā€¦ maybe cycling the AC power to it will be enough to kick in enough voltage to clear the brownout trouble. This is just and idea, and if you are a tech I will yield to your judgement.

5

Try a ā€˜warm resetā€™ by either pressing the reset button on the SMB/MMB or shorting out the jumpers on the SMB/MMB labelled reset. There was a bug with some of those panels where the AC light would continue to flash even though power is normal.

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6

Thanks Robert for your detail reply. Much appreciated. Actually we have done this several time in past as this trouble is persisting for more than 8 months now, but there is no change in status of this trouble. I even doubt battery charging circuit of MXL since I noticed that when we place new batteries, battery wire open trouble goes off but again after a period of time, it reappears (may be batteries not getting fully / properly charged).

Need help on how to get rid of this issue. Wondering if replacement of MMB3 PCB will fetch desired result but not sure if this could be due to bad Power supply unit or bad MMB3 PCB.
Anyone knowledgeable on the subject, please suggest.

Regards

Regards

7

Thanks for your suggestion, I will definitely try this out on first available opportunity. As you said, power supply voltage level is around 230-235V which is within normal range, however Power LED continously blinking. But I feel there is some issue in power circuit since battry wire open trouble also crops up with passage of time.

Regards

8

That AC Brownout fault is actually a problem with the MMB. All of those Siemen panels will give you that fault and the fix is a defective component on the board. Iā€™ve repaired a lot of things on those boards but havenā€™t figure out the fix for the Brownout yet. If I ever find the fix Iā€™ll post a comment. 1/26/24.

1/31/2024 I just found the reason for the AC Brown out failure. I have 2 different boards doing the same thing, turns out there was a missing component on the board, a very small capacitor added the part and it fixed my issue on both boards.