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Old 3rd June 2008, 05:22 PM   #1
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Lightbulb Capacitor help

Hi to all, this is my first post and its a help me sorry.
I am going to re cap my moth power amps and i have found a shop that has most parts in stock, my problem is which caps to use.
The caps fitted to the amps are samhwa 4700uf 63v and there is 2 others which are 470mFD 16v and 470uf 63v.
My question is what is uf and mFD i have been told that 2 of the caps are feedback caps and have to be right i need to know what the parts are before i send a order off as i dont want to blow up the amps.
Hope this makes sense


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Old 3rd June 2008, 05:41 PM   #2
Netlist is offline Netlist  Belgium
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mFD is often used instead of F. It's a source of confusion as mF is in fact milli(F) and uF or (F) is micro(F).

So, both caps are most likely 470F.
A picture would give more certainty.

Here's a nice page on capacitors:
http://www.uoguelph.ca/~antoon/gadgets/caps/caps.html

/Hugo
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Old 3rd June 2008, 06:07 PM   #3
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Thanks for that,its like school again!!!!!!!! lots of reading.
Thanks.
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Old 6th June 2008, 08:18 AM   #4
trodas is offline trodas  Czech Republic
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Another interesting thread (tough more specific about known bad caps and their replacement on voltage filtering circuits) are there:
http://capsmod.net/forum/viewthread....extra=page%3D1

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Old 9th June 2008, 03:47 PM   #5
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Thanks for the replys.
I have changed the caps and the feedback caps,only to still have a small problem!!!!!.
When i first switch the amps on i get a hum/buzz sound that last for a few seconds and the amps go quite and i then can use them.
The noise is only there when first switched on.
I thought the noise was a cap problem thats why i changed them and also there were 20yrs old.
So i am at a loss now as to were to look on the amp for the problem.
Any help please.
The amps are Moth 100 watt mono amps.
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Old 10th June 2008, 08:43 PM   #6
trodas is offline trodas  Czech Republic
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I would start replacing all the caps, becuase they are likely to be dried out already. 20 years can last only quality ones... VERY quality ones.
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Old 10th June 2008, 10:37 PM   #7
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Hi thanks for the reply, i have changed all the caps i could see and even the 2 feedback caps,but i still get a noise when first switched on.
Like a buzzing arking then all goes quite?????
I have att a pic dont know if it would be of help.
Pic to big will have to sort it and post it later.
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Old 10th June 2008, 10:48 PM   #8
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Is there anyone who can change the size of a file if i send it to them so i can put it on the page.
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