My SVS PB13-Ultra subwoofer stopped working. It happened after a voltage sag, probably followed by some spike.
After inspection, the fuse and a power resistor were blown.
I am sending you pictures attached. This is the PCB of the 1000W power supply of the sub driver. The missing indicated component is a 7 Watt, 5 ohm resistor.
Along with the other same resistor, they are the very first thing (after a usual varistor) that the AC circuit sees. I assume both these resistors are part of the LC filter at the input stage, the resistors probably dampening the filter's response.
These sand blocks are old fashioned resistors. I tried to find a similar one in mouser and digi-key, but no luck at all. 2 questions:
1) Is there ANY difference in replacing it with an ordinary wirewound power resistor, eg:
or a 10W one:
I didn't find any 5ohms, >= 7W, so I'd have to replace both resistors.
2) What is the story behind these sand blocks? Aren't they wirewound internally? Why did they stop being produced?
Funny thing is that the date signature in back of PCB is 2010. It is not that old! tks!