Electrolytic Capacitor with no polarity

[audiobeginne]

I Removed one cap from a Technics SUV85A amp from the pre Amp side. C311 capacitor has no polarity marking. But the replacement cap has Positive and negative marking on the new cap. How should I solder it?

 

[Hyperion]

How should I solder it?

You shouldn't, - you have the wrong type of capacitor. I assume you bought a 'Capacitor Kit' from somewhere, this is a common mistake made by some sellers of such kits. (AK member, capacitor kit vendor "affinity for artifacts" is not one of those).

This is important, the original Bipolar type capacitor can tolerate voltages of either polarity, whereas the replacement you have is 'Polar' meaning that it can tolerate voltage applied to it of one polarity only.

 

[mbz]

Schematic has C311 as 47uf/16V N (= Non-Polar)
As above, you cannot use a polar(+/- marked) cap as replacement.

edit appears to be in the audio path, I'd go with a Nichicon UES or similiar

 

[Gibsonian]

Get a non polarized cap and go

 

[Robisme]

You could make one with a couple 100uf back to back in series, if they would fit. 50uf should be close enough.

I assume you don't want to buy one capacitor and pay for shipping? Is there one in each channel or just the one?

You could start a private conversation with me and provide an address (if in the lower 48) and I could send you what you need.

Rob

 

[audiobeginne]

You shouldn't, - you have the wrong type of capacitor. I assume you bought a 'Capacitor Kit' from somewhere, this is a common mistake made by sellers of such kits.

This is important, the original Bipolar type capacitor can tolerate voltages of either polarity, whereas the replacement you have is 'Polar' meaning that it can tolerate voltage applied to it of one polarity only.

I bought the kit from Marblehead at Ebay. He is not an honest seller. All his full restoration kit is just capacitors. He put in wrong caps but I check carefully and did not install the non polarised caps but the values are still in spec so I solder back the old parts back. Thanks

 

[audiobeginne]

You could make one with a couple 100uf back to back in series, if they would fit. 50uf should be close enough.

I assume you don't want to buy one capacitor and pay for shipping? Is there one in each channel or just the one?

You could start a private conversation with me and provide an address (if in the lower 48) and I could send you what you need.

Rob

There are two such caps but I measured the values and it's surprising still within spec after 35 years. Japan knows what they are making

 

[rickl]

There are two such caps but I measured the values and it's surprising still within spec

this is probably the next best thing to do. Put it on your list for your next project.

He put in wrong caps but I check carefully and did not install the non polarised caps but the values are still in spec so I solder back the old parts back.

it happens. I'm happy you posted the question.

 

[audiobeginne]

this is probably the next best thing to do. Put it on your list for your next project.


it happens. I'm happy you posted the question.

Can we replace with a film capacitor like Wilma film cap?

 

[rickl]

Can we replace with a film capacitor like Wilma film cap?

you can but a 47uF is pretty large (and might be difficult to find and $$$$).

use a pretty green UES cap

 

[jheu02]

Can we replace with a film capacitor like Wilma film cap?

I personally prefer the Fred or Barney (Rubble) caps. Really has that vintage sound...