Need help identifying what kind of capacitor that are used, see pictures. It's in an old Heatkit AV-3 tube voltmeter that I'm restoring.
They're rated at 33nf, 47nf / 600v. 120nF 400v. And 2uF / 200v.
I wonder that kind of capacitor it is, and how likely it is that they'll fail? Haven't measured them yet, but if it's something unreliable like paper in oil capacitors I'll definitely replace them anyway...
They're rated at 33nf, 47nf / 600v. 120nF 400v. And 2uF / 200v.
I wonder that kind of capacitor it is, and how likely it is that they'll fail? Haven't measured them yet, but if it's something unreliable like paper in oil capacitors I'll definitely replace them anyway...
Yes, these types don't have the best coating/seals and have a history of failing over time (they take on humidity).
You should replace them, any modern film cap of the same rating should be OK. It'll probably be larger than the part it replaces but it looks like you've got plenty of room.
You should replace them, any modern film cap of the same rating should be OK. It'll probably be larger than the part it replaces but it looks like you've got plenty of room.
Polyester. Measure them, if they are good you can leave them or replace them. Probably the sound will change a bit with the new capacitors.
The beige ones are "mustard caps" from Mullard, Philips, MBLE etc, and they are mylar, bulky but normally quite robust and durable. They shouldn't need replacement, but after 50~60 years, some may have failed.
I am not sure about the green Sangamo: it is probably a paper cap, in which case it should be replaces
I am not sure about the green Sangamo: it is probably a paper cap, in which case it should be replaces
Same thing. Mylar is just a DuPont patented trade name for sheet polyester, that they first produced many moons ago..
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The first one (below) is called "Mustard Caps".
I think that they were Italian production. You could find them in Hiwatt, Marshall, Vox amps, Arbiter Fuzz-Face, Vox Tone-Bender and Wah effects, JEN, Davoli, Crumar, Farfisa keyboards, amps and miscellanous devices.., These are highly regarded in the DIY musical instrument world...
T
I think that they were Italian production. You could find them in Hiwatt, Marshall, Vox amps, Arbiter Fuzz-Face, Vox Tone-Bender and Wah effects, JEN, Davoli, Crumar, Farfisa keyboards, amps and miscellanous devices.., These are highly regarded in the DIY musical instrument world...
T
That's right. Only in our country, the term Polyester caps is commonly used, Mylar less often.
That's possible, yes... Philips had factories all over the world at that time, notably in Italy.
T
In Italy it was Elcoma, in France RTC, etc.
Basically all the same products, with minor local variations
Basically all the same products, with minor local variations
Thanks for all the answers. Definitely will replace the green Sangamo cap, since it's a paper cap.
Didn't recognize the Mullard caps at first, but looks like them. If so they're are polyester and should be ok? Maybe I leave them, or replace them and use them for another (audio) project.
I don't recall them going bad, certainly not on a broad scale.
Hugo
Hugo
You might paint them a more pleasant colour - that'll going to have a strong confirmation bias effect 😉
I suspect they work fine.
I suspect they work fine.