Re: Fire Lite MS5024UD

[Jim Rojas <jrojas@xxxxxxxxxxxx>]

On 11/28/2014 9:08 PM, ABLE1 wrote:
> Ok, So just to spark a few post here I thought I would share
> my latest challenge.  And to maybe get some insight at the same time.
>
> I have just inherited a MS5024UD panel.  Trying to evaluate the
> problem has become a problem.  Panel is showing a F 4 trouble.
>
> According to the manual this is a Fault on Zone 4.  Cool that was easy.
>
> Well when I check the resistance of the loop I get 4.76k worth.
> That is correct.  I placed a 4.7K resistor across the zone.  No Change.
>
> My thought is that the mother board has a problem with Zone 4 OR the
> panel has some program issue that is causing the fault.
>
> So my question is:
> Any of you guys know anything about this panel enough to give some insight??
>
> Thanks,
>
> Les
>
>

I use to field repair hundreds of fire panels before NFPA72 stated we
couldn't do it anymore.

I am assuming you removed the field wiring before you put the resistor
across it? Did you swap zones around? Try swapping zone 3 & zone 4.
(make sure you are swapping same class zones (Class A or Class B)

If yes, the panel most likely took a strike or a surge on that zone. It
is a very common problem. There is a diode or resistor on the board near
the zone. It is most likely an SMD diode. If not, use a meter and test
the diode. They are designed to blow to save the panel.

Remove field wiring on zone 3 & 4 (Must be same Class). Then take a
voltage reading across zone 3. Then take a voltage reading across zone
4. This will help to determine if it is a field wiring problem or the panel.

I can't tell you how many times in my 30 years I have walked on a huge
fire system service call with nothing more than a meter, soldering iron
and a box full of parts, and start replacing common components that fail.

It is a lost art, just like window foiling... :)

Jim Rojas