About Copper caps

PabloTincho

PabloTincho

Super Member
I have a tuner with copper caps, the tuner is a NEC T-710 and is a very good tuner, the tech who is doing the recap told me "I am not keen to replace the Copper caps... It would remove that particularity from the tuner"

What do you guys make about copper caps, should I replace those ?

Here is a review of the tuner " The NEC T-710 is a 4-gang, dual-gate front end
MOSFET design, that features copper foil capacitors. That means that
it still sounds like new, after 15 or so years, and is very quiet."


Do you guys have any experience with copper caps ? Do they last forever ? Should I change those copper caps
here is a picture of the copper caps top left

T710_MainBd.jpg

thanks for your time
 
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The tuner is almost 40 years old, I want the tuner to last another 40 years, why not ?
Do coppers caps last forever ?
 
PabloTincho said:
Do you guys have any experience with copper caps ? Do they last forever ? Should I change those copper caps
here is a picture of the copper caps top left
Click to expand...
They look like 'Noble' Polystyrenes to me, yes they do last forever and are extremely good quality polystyrene capacitors - you won't be able to find a better replacement, so I recommend you leave them alone. Note they are very sensitive to heat - so don't go 'bulk reflowing' the solder underneath them - when desoldering them most people use a heatsink - that's how heat sensitive they are. They are also sensitive to some solvents - which will melt the body of the capacitor and ruin them - beware.
PabloTincho said:
Do coppers caps last forever ?
Click to expand...
The ones in the picture look in 'rude health' to me, my strong recommendation is to leave them alone.
PabloTincho said:
What is so special about copper caps ?
Click to expand...
They have Polystyrene dielectric (the best), they were made by Noble (the best), will you be able to find better ones today? - no.

Did I mention leaving them alone? :)
 
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I was going to say they look like polystyrene caps.

Polystyrene caps in general are exceptionally stable and don't tend to break down with age.

As are film caps, ceramic caps (usually) and basically any type except electrolytic or paper.

Also if you were to replace them, you'd no doubt mess up the alignment of the tuner.
 
You are going to trust that tech to perform an alignment and he can’t recognize a copper foil polystyrene cap in that section . I’d be wondering.
PS If you are only changing ecaps, alignments are not usually required
I see those orange ecaps which are low leakage I hope you are planning to use similar ie. nichicon UKL
 
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rcs16 said:
You are going to trust that tech to perform an alignment and he can’t recognize a cooper foil polystyrene cap in that section . I’d be wondering.
Click to expand...
Reread the original post. The tech not only recognized the copper foil caps, he also advised against replacing them.

OP, it seems your tech knows his business quite well, while from your questions it appears you may be on a steeper bit of the learning curve. Learning is good, as is asking questions, however you've received sound advice, both from your tech and members here. Don't let any bias - based on misinformation or lack of knowledge - prevent you from heeding it.
 
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Polystyrene are very reliable with one big exception: they do not like heat. Hitting them with a soldering iron to pull them out of circuit for measurement is very likely to shift their value, so its generally suggested to not touch them unless you have no choice in the matter.
 
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