Help to identify old capacitor

[synthiaks]

That's right.....

But  it's not worth checking that far if the capacitance doesn't even measure normal.....

ok

 

[LevinGuitar]

This is the ebay seller I ordered them from, he have a lot of old stuff if someone want to take a look.

https://www.ebay.de/usr/roehrenseele?ul_noapp=true



Thanks again for replies!

 

[synthiaks]

????

0,22 is 0.22.  Surely film.  The other pic is 1/250, also film in that size.

This got me interested so i did some research The Silver one has MP written on it. As it is a German Capacitor

MP=

"MP-Kondensatoren (Metall-Papier) besitzen Papier als Dielektrikum, das entweder ölgetränkt, ölimprägniert oder hartwachsimprägniert ist. Ältere (vor 1980) Ölpapierkondensatoren (PIO: Paper in oil capacitor) können das im Brandfall giftige PCB enthalten ! Es gibt sie im zylindrischen Alubecher mit Schraubanschluß, im rechteckigen Alubecher, oder seltener als axiale Kondensatoren. "

 

[synthiaks]

the more i think about it, I don't understand why a 0.22uF can't be a paper cap?

 

[JohnRoberts]

They might measure correct  uF but still be DC Leaky, or am i wrong here?

you can measure that too...

JR

Im not a big tube guy but isn't this caps used to Couple tube stages?

So if they are ok at 100V but starts to let through DC at 200V they are unusable for High voltage but could be used in some Guitar Filter i guess

 

[Murdock]

The manufacturer of those .22uF paper caps is called "Hydra". They are still in business

 

[LevinGuitar]

Thanks Murdock!

 

[synthiaks]

you can measure that too...

JR

If one wouldn't use a Heathkit TI-28 or similar is this as easy as putting voltage on one end of the capacitor and a resistor to ground on the other and then measure voltage drop (if any) over the resistor or is it more to this?

Not that I would like to put 400V on my bench just like that ( as said, I'm not a tube guy)

S

 

[Tubetec]

I have one of these units , its ancient ,but it still works ,tests up to a 450 volt cap and gives a reading on the magic eye.  You'll most likely need to rewire the mains with three core cable and plug to make it safer , Id also be careful not to touch the terminals while you do the leakage test as there could be hundreds of volts across them .

 

[synthiaks]

I have one of these units , its ancient ,but it still works ,tests up to a 450 volt cap and gives a reading on the magic eye.  You'll most likely need to rewire the mains with three core cable and plug to make it safer , Id also be careful not to touch the terminals while you do the leakage test as there could be hundreds of volts across them .

I have 2 different units but both need some service. I haven't found time to do it. Honestly the time it would take to test a paper capacitor for leakage I have a brand new foil one installed.  But still it would be cool to test them after I remove them. I could still sell the "good" ones on eBay for 5$

BTW the IT-28 goes to 600V so I guess you try and focus when using the terminals on that one

 

[scott2000]

This simple method for testing leakage has been linked here before somewhere.... not sure of the consensus on it though.... accuracy where it matters etc...

https://www.youtube.com/watch?v=ASqMIFotKVo

 

[JohnRoberts]

If one wouldn't use a Heathkit TI-28 or similar is this as easy as putting voltage on one end of the capacitor and a resistor to ground on the other and then measure voltage drop (if any) over the resistor or is it more to this?

Not that I would like to put 400V on my bench just like that ( as said, I'm not a tube guy)

S

yes but of course do it carefully... could be as simple as applying expected voltage to one end, and VOM current meter from other end to ground.

When I was designing my outlet tester  that required a very high insulation touch probe, I borrowed this insulation tester to confirm the high input impedance of my mosfet input buffer. (Off scale so >500M ohm at 500V). Before borrowing the dedicated tester I did some bench tests with a roughly 500V AC supply I cobbled together by stacking several 120V transformer primaries in series and a VOM to ground on the other end. 

You also need to decide if this is worth your trouble... old film caps are probably good, old electrolytic caps probably questionable.

JR

 

[Khron]

In signal stages it's not even all that bad, but there are dozens (or even hundreds, if not more) of photos online of failed metallized-paper Rifa X2 / Y2 capacitors (used across the incoming mains)... Just sayin'...

https://www.google.com/search?q=rifa+failed&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjNn-y9_8nnAhVmxaYKHZoWAvQQ_AUoAXoECBMQAw&biw=1622&bih=740

(The logic being, since these were supposed to be designed for 24/7 across-the-mains usage, and still crapped out... How much can you trust even older parts using the same technology, but made for possibly less strenuous duty?)

 

[synthiaks]

In signal stages it's not even all that bad, but there are dozens (or even hundreds, if not more) of photos online of failed metallized-paper Rifa X2 / Y2 capacitors (used across the incoming mains)... Just sayin'...

https://www.google.com/search?q=rifa+failed&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjNn-y9_8nnAhVmxaYKHZoWAvQQ_AUoAXoECBMQAw&biw=1622&bih=740

(The logic being, since these were supposed to be designed for 24/7 across-the-mains usage, and still crapped out... How much can you trust even older parts using the same technology, but made for possibly less strenuous duty?)

Grrr....

For a Swede living abroad, these epoxy guys give me a bad rep...

I have had them fried in everything from sawingmachines to EMT plates

JR:
Ok, personally I wouldn't wanna mess with 600V on my bench it's scary enough that the IT-28 has it on the connectors if choosen.

Going through the hassle would probably only be so that I can say with serious voice something like:

"Man, that coupling cap between first/second  stage was leaking like titanic after 60V" And knowing this is true and not BS

Or sell the "good" ones on eBay

S

 

[synthiaks]

This TE-46 also has 600V as MAX. The Leakage is not measured with the eye though, it has a MA meter.

 

[Whoops]

Honestly the time it would take to test a paper capacitor for leakage I have a brand new foil one installed.

Definitely