meksikan Posted October 18, 2014 Share Posted October 18, 2014 (edited) Sorry for this being my first post and if this has come up a lot, I couldn't find much info online. I bought my pro media 2.1 speakers in the early 2000's and recently it stopped working. I took the back off and took a look around the board after it stopped working. The speakers would turn on for a second, then turn off. I would hear a click after the speakers would turn off. I traced the problem to the position C118 transistor. At least I think it's a transistor. Anyhow it's blown and blackened. I found one post online saying it may just be a noise filter or something and it could be safe to just remove it and not use it, but I don't want to do so, and further damage the circuit board. If anyone could help me out, i would bee forever grateful. Also, sorry if this post is a wall of text as i am posting this from my phone. Edit: if this post is in the wrong forum, mods please feel free to move this. Edited October 18, 2014 by meksikan Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 19, 2014 Share Posted October 19, 2014 C118 would be a capacitor (hence the 'C' designation). A transistor would have a 'T'. Capacitors will work as filters, but without the schematic it would be hard to troubleshoot. Welcome to the forums. Bruce Quote Link to comment Share on other sites More sharing options...
hydro_pyro Posted October 19, 2014 Share Posted October 19, 2014 A transistor would usually be labeled as "Q." It's less common to use "T" as a designation. Yes, C is a capacitor. Usually if they're an electrolytic can capacitor, they explode and leak brown juice upon failure. It's odd for a capacitor to be blackened. Usually a cap that has enough current across it to blacken it is being used as a power supply component. Quote Link to comment Share on other sites More sharing options...
meksikan Posted October 19, 2014 Author Share Posted October 19, 2014 Hello and thanks for the replies. @hydro it is indeed on the power supply portion of the circuit board. Would I have to replace it or can I just remove the damaged part and attempt to turn it on? Quote Link to comment Share on other sites More sharing options...
hydro_pyro Posted October 20, 2014 Share Posted October 20, 2014 It's probably a filter cap, to take away the AC "ripple" from the output of the DC supply. I wouldn't advise turning it on without it. The power amp will tend to pass on the ripple as a loud hum, and other circuitry may be damaged. Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 20, 2014 Share Posted October 20, 2014 A transistor would usually be labeled as "Q." It's less common to use "T" as a designation. You are certainly correct... I was half asleep when I typed that. Quote Link to comment Share on other sites More sharing options...
WMcD Posted October 22, 2014 Share Posted October 22, 2014 Look here.. https://community.klipsch.com/index.php?/topic/118802-full-set-of-schematic-diagrams-for-promedia-21-system/?hl=schematic#entry1752639 WMcD 1 Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 22, 2014 Share Posted October 22, 2014 I couldn't find C118 on that diagram. It seems it should be in the power supply portion, and the only cap without a designation is the 0.001u on the A/C switch. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 22, 2014 Share Posted October 22, 2014 I thought that when a cap blew it was normally caused by a problem up circuit some where and it was the result, not cause of the problem. Quote Link to comment Share on other sites More sharing options...
hydro_pyro Posted October 30, 2014 Share Posted October 30, 2014 Most of the time, when caps blow its because they're defective. The circuit never exceeds the cap's voltage rating. Others just wear out or go dry over the years, but they don't necessarily explode. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 30, 2014 Share Posted October 30, 2014 They explode when you hook them up backward. I had a pregnant cap just last year. Quote Link to comment Share on other sites More sharing options...
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