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What it is...


I have an Infinity BU-120 Powered Home Theater Subwoofer that was given to me by my father who no longer has any use for it as his receiver does not have a sub out on it.

What it does...


When turned on it has a mild volume fluttering sound. This can be heard simply just by being pluged into the wall and without anything in the input.

What I have found...


I have found through searching that it is the 50 volt C6 capacitor and the Infinity service manual recommends trading it out with a 100 volt. Upon further investigation I have found the service manual for the sub which covers this in great detail as well. Here is the Infinity BU-120 Service Manual . And the specific problem in question is addressed on page 15 of the manual and can be fixed with Infinity part# 30722 or JBL part# 30721.


I have found some of the components that combine the 30722 or 30721...
C6 – (10uf 100v NPE cap)
R23 – (20k 1/2W resistor – used only on models BU120, HTS-20 revA)
R46 – (47 1/4W resistor)

What I would like...


I need some help as far as what cap it is on the amp within the sub, this may be more obvious once I have the parts in hand. The srvice manual lists this as the specific action to repair this issue "Replace C6,R23, C24, R46 with Infinity part# 30722". I have yet to locate the C24 – (100nF 50v cap). I also need verification from someone that knows what they are talking about that these parts I have listed will indeed work.


 

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were you ever able to fix this subwoofer. i am trying to fix mine and am in the same boat. but i have 2 burned resistors R57 and R52
 
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