What is this capacitor?

[sound guy]

I am repairing a pk klarity sub amp I have a bad ceramic capacitor that has the number 1815 printed on it. I don't have schematics and the cap is ruined so I don't know the value. Does anyone know?

 

[Nigel Goodwin]

Post a picture, so we can see where it is, and what it might be doing.

 

[ahsrabrifat]

The number 1815 on a ceramic capacitor does not directly indicate its capacitance value in the standard capacitor code format. It can be a proprietary marking.

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[sagor1]

Could it be some form of MOV? Post a picture of it.... Are there identical ones nearby as well? Picture those too.

 

[sound guy]

Yes the 1815 is a proprietary marking that's why I don't know the value don't know who made it or where the PK company gets its ceramic capacitors from. Unfortunately the cap crumbled to pieces when I tried to remove it from the PC board and there are no others like it on the unit. It is one of those small pancake caps.

 

[Nigel Goodwin]

Yes the 1815 is a proprietary marking that's why I don't know the value don't know who made it or where the PK company gets its ceramic capacitors from. Unfortunately the cap crumbled to pieces when I tried to remove it from the PC board and there are no others like it on the unit. It is one of those small pancake caps.

POST A PICTURE - if the component has crumbled, then post a GOOD picture of the board where it was, close up and one wider. What colour was the crumbled component?.

 

[sagor1]

Most caps do not just "crumble". Protective devices like MOVs can split, blow off a piece or crumble when they "protect" something due to a fault elsewhere on the board. The fact that there are no other similar devices on the board suggests it is not a regular cap. A picture of the board around the device may give a clue, as Nigel says.
Otherwise everyone is just guessing, which will not solve your problem...

 

[Tony Stewart]

How large was it? What makes you think it was ceramic? Was it polarized?

 

[sound guy]

 

[sound guy]

The ceramic capacitor was mounted next to the 120v input and it arked to it burning it out

 

[sound guy]

 

[Diver300]

One photo appears to show a space for a component labelled R10. The wires for that have changed from one photo to another, and the shape is quite distinctive.

That could have been an inrush limiting resistor, something like this:- https://www.cantherm.com/wp-content/uploads/2018/08/MF72_AUG_2018.pdf

Those can be damaged if something else takes too much current. The inrush limiting resistor is basically in series with the whole appliance. In some cases there is a relay that shorts them out after the initial inrush that happens at turn-on.

The item with T1749R is a filter. There is some odd substance at the other end of that. Is that from another component failing or is it some glue or something to hold things together? If it's glue or similar, has the same stuff been used on the component that failed?

 

[Nigel Goodwin]

View attachment 148985

The picture clearly shows it marked as R10 - so a 'resistor' rather than a capacitor, and most probably actually a thermistor or VDR used for surge limiting or over voltage?. You need to draw that part of the circuit out, to see what it's actual function is.

 

[schmitt trigger]

I join the chorus in believing that it is an inrush limiting resistor, probably even an NTC thermistor.
Like the attached image, and it is easy to confuse it with a capacitor.

 

[sound guy]

Yes the odd substance is some black goo that is all/ through the amp. I will pull it out again and trace the circuit but I belive you are right that it is a resister. Thank you

 

[Tony Stewart]

This can get destroyed by intermittent connection of power when the NTC was hot but bulk cap discharged causing the Inrush Current Limiter (ICL) to fail. PC PSU's normally have a relay to prevent rapid restart so that the ICL with the NTC characteristics is not overloaded.

DigiKey caries a wide range of ICL's.

Does this Single Event Burnout (SEB) failure sequence ring any bells?