NAC 1 fried on my firelite ms 9200 ud

My firelite ms 9200 ud’s nac 1 is fried I know it is because I hooked up an alarm to it and it didn’t receive it’s power. Everything was wired correctly could someone tell me how to replace this nac card

Just a few questions:

Are you getting a NAC trouble at all on the 9200? What signal are you using, and do you have it wired as Class A or Class B?

I do believe it is permanent dead and I will have to sadly replace the board in the panel however my idea is that I can buy ms 9200 udls replacement board and just put that in the 9200 ud cabinet but I need to get a job first

Panel will need to be replaced…

I would troubleshoot further before giving up…

[quote="The fire alarm dude" post_id=87087 time=1590347119 user_id=6131]

I do believe it is permanent dead and I will have to sadly replace the board in the panel however my idea is that I can buy ms 9200 udls replacement board and just put that in the 9200 ud cabinet but I need to get a job first

[/quote]

My questions still remain: Are you getting a NAC trouble at all on the 9200? What signal are you using, and do you have it wired as Class A or Class B?

Some signals do not play nice with the 9200 (namely Simplex devices made since the 90s). If you have the system wired as Class B when it expects Class A (or vice versa), it will not function properly.

I honestly do not know what class of wiring a or b is. But I can tell you that a trouble does come in on the 9200 ud and it won’t clear when it resistor it off. Could you explain class a and class b wiring to me please? That would be great

[quote="The fire alarm dude" post_id=87119 time=1590887526 user_id=6131]

I honestly do not know what class of wiring a or b is. But I can tell you that a trouble does come in on the 9200 ud and it won’t clear when it resistor it off. Could you explain class a and class b wiring to me please? That would be great

[/quote]

Class B is the standard form of wiring where there’s a resistor on the last device on the circuit. Class A is when the wire goes out from the panel, all the devices are wired and the wiring goes back to the panel after the last device. Generally you need an extra card to do this.

Did you meter out the NAC? Like put a DC meter on the NAC terminals, and measure in alarm and supervisory voltage?

In normal condition, if you were to meter the terminals (red probe on B+, black probe on B-), you should receive a reading of -24v because NACs are supervised by means of reversed polarity. In alarm condition, that should swap to a positive 24v.

There could very well be a fuse blown on the NAC, in which case you’d have to find the fuse, desolder it, and resolder a new one if you wanted to fix it. They’re not meant to be field-serviceable and Fire-Lite actually wants you to replace the board if a fuse gets blown.