I'm having some issues with a PCB in an alarm unit. I think the unit shorted. I'm now trying to identify the broken component to replace it.
The board is mains powered, but also has a battery - attached in the pictures red and black wires - and in the reverse picture positive terminal with the square box.
There is a rectangular component between the two terminals - in the picture this is two vertical silver strips with a black middle section running between the bat + and bat- terminal. No conductance between top and bottom on multimeter. If I touch this - the unit sounds making me think this may previously have had a length of wire between the terminals that has burnt out.
I tried putting a length of wire between the two terminals pictured and circled - and the unit come back to life.
Should I solder a bypass or is this potentially dangerous on a 6V battery supply and mains?
I'm confident nothing else is wrong downstream - I know what caused the short and this has been fixed.
- Is this a fuse or something else?
- Can it be replaced?
PCB front side:
PCB back side: