SMD Capacitor ID

[Bx Bandit]

Hello,
I need to replace a surface mount capacitor that has failed on my boiler PCB. The problem is I have no idea what value it is. It tests o/c Can anyone help please?

 

[dougy83]

How do you know it has failed?

small value capacitors will show as o/c if you use a resistance meter. Borrow a capacitance meter to measure the value (once you've removed it from the PCB)

 

[Bx Bandit]

Thank you Dougy, well, the capacitor looks a tad 'fried' as the pcb was exposed to a brief erroneous short if that makes sense. All the others show a level of impedance that varies as they 'fill up'. I take your point about testing it off the board, not sure I can get a cap tester though. is there any way to identify it's value?

 

[Nigel Goodwin]

Thank you Dougy, well, the capacitor looks a tad 'fried' as the pcb was exposed to a brief erroneous short if that makes sense. All the others show a level of impedance that varies as they 'fill up'. I take your point about testing it off the board, not sure I can get a cap tester though. is there any way to identify it's value?

You obtain the circuit diagram, or parts list, and read it off that - however, it's EXTREMELY unlikely that you could obtain either of those.

It's also very unlikely that the capacitor is damaged anyway, they aren't the sort of things that are easily damaged in such accidents.

 

[Speakerguy]

He never said what type of cap it was....

 

[dougy83]

Does it have any marking (apart from char)?

 

[Bx Bandit]

Hi,
Thanks for your replies. No there are no markings, unless it's under the cap on PCB side. It's very small, beige in colour, brick shaped and with two metal contacts either side like a sandwich. It looks like this: https://img.alibaba.com/photo/204847595/SMD_Ceramic_Capacitor_0805_105_16V.jpg

 

[Sceadwian]

If the capacitor is damage the only way to find out is from the schematic. If it's not you have about a thousand other components to check.