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Author Topic: Help with capacitors...  (Read 1306 times)

guitarbth

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Help with capacitors...
« on: February 10, 2005, 12:57:32 PM »

Hi all...
So Im fairly new at working on my own gear and I need some help with a capacitor replacement. I have a Crown DC300A that was acting up on me. Yesterday I was fortunate enough to have an aquaintence at Oceanway Nashville put it on the bench and walk me through reading the schematic, checking some test points, and isolating the problem. We came to the conclusion that there are a few bad capacitors in the circuit and that I'll need to replace them. Im going to pick up the caps at a local electronics store this weekend and will be doing the replacement by myself and want to double check with you guys first about a few things. My acquaintence told me to make sure the polarity on the caps was right when I put them in or I could be in a heap of trouble. So, the style of caps that sit up vertically on the board have a line down one side... is this the positive side? Also, one of the caps that Im replacing is one that sits on its side longways and has a groove on one end. In case Im only able to get the other style cap (the kind that sits up vertically), I'll need to know which end of the horizontally placed cap is positive and which is negative. Is the end with the groove in it the negative side? Any other info that may be helpful is totally welcomed. Wow... I hope that made sense. Thanks in advance for any help you can offer.

Brandon
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U1176

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Re: Help with capacitors...
« Reply #1 on: February 10, 2005, 02:08:00 PM »

guitarbth wrote on Thu, 10 February 2005 13:57


Hi all...
So Im fairly new at working on my own gear and I need some help with a capacitor replacement. I have a Crown DC300A that was acting up on me. Yesterday I was fortunate enough to have an aquaintence at Oceanway Nashville put it on the bench and walk me through reading the schematic, checking some test points, and isolating the problem. We came to the conclusion that there are a few bad capacitors in the circuit and that I'll need to replace them. Im going to pick up the caps at a local electronics store this weekend and will be doing the replacement by myself and want to double check with you guys first about a few things.



Congrats!

guitarbth wrote on Thu, 10 February 2005 13:57


My acquaintence told me to make sure the polarity on the caps was right when I put them in or I could be in a heap of trouble.



True.

guitarbth wrote on Thu, 10 February 2005 13:57

 
So, the style of caps that sit up vertically on the board have a line down one side... is this the positive side?



No. First of all a Capacitor which 'sits up vertically on the board' is called a radial capacitor. They typically have a line down one side but this indicates the negative lead. Have a closer look you should discern some kind of arrow pattern on the stripe and a '-' symbol.

guitarbth wrote on Thu, 10 February 2005 13:57

  Also, one of the caps that Im replacing is one that sits on its side longways and has a groove on one end.



This type of package is called an axial type.

guitarbth wrote on Thu, 10 February 2005 13:57


In case Im only able to get the other style cap (the kind that sits up vertically), I'll need to know which end of the horizontally placed cap is positive and which is negative. Is the end with the groove in it the negative side?



The end with the groove denotes the positive lead again you should be able to confirm this if you look closer.

guitarbth wrote on Thu, 10 February 2005 13:57


Any other info that may be helpful is totally welcomed. Wow... I hope that made sense. Thanks in advance for any help you can offer.

Brandon




You're welcome as always Brandon, nice to hear from you again.
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guitarbth

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Re: Help with capacitors...
« Reply #2 on: February 10, 2005, 04:16:56 PM »

Exactly what I was looking for... thanks so much.

Brandon
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David Kulka

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Re: Help with capacitors...
« Reply #3 on: February 11, 2005, 01:10:13 AM »

DC-300A's used a few non-polarized capacitors.  These are special types with no polarity, ie no + or - side.  If you are repacing the NP caps in your amp, be sure the new ones are also NP.
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