What does this Capacitor identification mean on a circuit diagram?

JohnB47

Hi all.

I'm embarking on a repair on my ancient Arcam Alpha 5 CD player and I've found a great forum thread (very old but still relevant) on a site called Pink Fish Media, giving me some good advice on what the problem might be.

I can see, on the circuit diagram I've found, that the suspect capacitor is shown as C416 470U ELST and the thread identifies this as a 470 microfarad electrostatic capacitor.

However, nearby I see another capacitor and it's labelled C415 470N PEST. Another is labelled C414 100N PEST. These two aren't ones that are recommended to be replaced but I'm curious about those labels. I've searched and can find no info.

Anyone any ideas?

DiseasedBunny

The N means nanofarad, so it’s 1000 times smaller than microfarad 

Cornucopia

Your 470uF will be an electrolytic capacitor, and these can deteriorate with age.    The other two will be different composition and are not likely to deteriorate.   

You'll need both the voltage and capacitance in order to replace your suspect capacitor, and the new one will need to be installed in the same polarity as the old one.

JohnB47

Thanks both.

The thread does recommend replacing the electrostatic one with a higher voltage than that fitted (25V), so I'll bear that in mind.

Any idea what PEST is supposed to signify?

JohnB47

Just been doing a bit of searching. One type of capacitor is 'polyester film'. Could that be what PEST is referring to?

Cornucopia

JohnB47 said:

Just been doing a bit of searching. One type of capacitor is 'polyester film'. Could that be what PEST is referring to?

Yes - Polyester Film would be consistent with those values.   "PEST" would seem to be a proprietary code - not come across it before, and Google says:  meh.

getmore4less

JohnB47 said:

Hi all.

I'm embarking on a repair on my ancient Arcam Alpha 5 CD player and I've found a great forum thread (very old but still relevant) on a site called Pink Fish Media, giving me some good advice on what the problem might be.

I can see, on the circuit diagram I've found, that the suspect capacitor is shown as C416 470U ELST and the thread identifies this as a 470 microfarad electrostatic capacitor.

However, nearby I see another capacitor and it's labelled C415 470N PEST. Another is labelled C414 100N PEST. These two aren't ones that are recommended to be replaced but I'm curious about those labels. I've searched and can find no info.

Anyone any ideas?

Check the manuals and service guides for other Arcam products this google found loads.

https://www.google.com/search?q=c415+470n+pest

JohnB47

getmore4less said:

JohnB47 said:

Hi all.

I'm embarking on a repair on my ancient Arcam Alpha 5 CD player and I've found a great forum thread (very old but still relevant) on a site called Pink Fish Media, giving me some good advice on what the problem might be.

I can see, on the circuit diagram I've found, that the suspect capacitor is shown as C416 470U ELST and the thread identifies this as a 470 microfarad electrostatic capacitor.

However, nearby I see another capacitor and it's labelled C415 470N PEST. Another is labelled C414 100N PEST. These two aren't ones that are recommended to be replaced but I'm curious about those labels. I've searched and can find no info.

Anyone any ideas?

Check the manuals and service guides for other Arcam products this google found loads.

https://www.google.com/search?q=c415+470n+pest

Thanks for that. I see numerous mentions if PEST. Perhaps that's my curiousity settled. No reason for other otherwise . 

JohnB47

Cornucopia said:

JohnB47 said:

Just been doing a bit of searching. One type of capacitor is 'polyester film'. Could that be what PEST is referring to?

Yes - Polyester Film would be consistent with those values.   "PEST" would seem to be a proprietary code - not come across it before, and Google says:  meh.

Yep. Me too, doing a search. Ta

Micron

JohnB47 said:

However, nearby I see another capacitor and it's labelled C415 470N PEST. Another is labelled C414 100N PEST. These two aren't ones that are recommended to be replaced but I'm curious about those labels. I've searched and can find no info.

Anyone any ideas?

What about:  Polyester Stacked  =  PE ST

It would look like a small cube rather than a cylindrical wound type?

Just an example:

Coated type  https://uk.farnell.com/kemet/r60qn3100aa30j/cap-0-1-f-1-kv-5-pet-radial/dp/2710234

Uncoated type  https://uk.rs-online.com/web/p/film-capacitors/4833933

JohnB47

Micron said:

JohnB47 said:

However, nearby I see another capacitor and it's labelled C415 470N PEST. Another is labelled C414 100N PEST. These two aren't ones that are recommended to be replaced but I'm curious about those labels. I've searched and can find no info.

Anyone any ideas?

What about:  Polyester Stacked  =  PE ST

It would look like a small cube rather than a cylindrical wound type?

Just an example:

Coated type  https://uk.farnell.com/kemet/r60qn3100aa30j/cap-0-1-f-1-kv-5-pet-radial/dp/2710234

Uncoated type  https://uk.rs-online.com/web/p/film-capacitors/4833933

Yes, spot on. I've removed the lid of the Alpha 5 now and I can see C416 and the other two PEST types. The PEST ones are indeed little rectangular box ones, just like those shown on your links.  So that's that answered.

Some posts on the thread on that other site mentioned weeping or discoloration around C416 but I can't see anything amiss. Perhaps I need to remove the board and look at the soldered side.

I've cleaned the Laser lens now - it seems there's only one lens there. I was expecting a sort of transmitter lens and a receiver lens. I might look into that in case I need to clean something else too.