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rjd2
Joined: Sep 02, 2007 Posts: 236 Location: philly
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Posted: Fri Dec 06, 2013 1:49 pm Post subject:
Help on a capacitor substitution Subject description: can a .047uf bypass go up or down? |
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hi all, hopefully a quick question.
restoring a Yamaha CS-40M. on the attached board, there are a bunch of .047uf poly caps that look like they function as bypass caps to the -15V rail, and are toast. i need to sub them out.
i've got a gang of caps laying around, but not enough .047uf(and ceramic, at that) to do the whole board. my question: can i go up or down on the value for this application, you think? and can i use ceramic? thanks for the help.
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Osal
Joined: Aug 16, 2011 Posts: 147 Location: Here
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Posted: Sun Dec 08, 2013 10:16 am Post subject:
Re: Help on a capacitor substitution Subject description: can a .047uf bypass go up or down? |
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rjd2 wrote: | hi all, hopefully a quick question.
restoring a Yamaha CS-40M. on the attached board, there are a bunch of .047uf poly caps that look like they function as bypass caps to the -15V rail, and are toast. i need to sub them out.
i've got a gang of caps laying around, but not enough .047uf(and ceramic, at that) to do the whole board. my question: can i go up or down on the value for this application, you think? and can i use ceramic? thanks for the help. |
These capacitors hold the analog value from the demultiplexer ym617. You can read the explanation in pages 28-29 of the hardware manual:
here
It is interesting the lecture from page 1 to 29 though.
So, as I understand, the capacitors must be enough large to hold the voltage value during 5ms but enough small to charge a new value during only 80 μs for each 5ms without a noticeable delay.
I would go for new 0.047uF polyester capacitors. _________________ electronic-sea.net |
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