Author Topic: capacitor replacement type  (Read 1299 times)

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Offline CramboneTopic starter

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capacitor replacement type
« on: July 18, 2020, 11:02:23 pm »
I'm looking for the following 2 capacitors but I'm unable to locate is there some other type I could use or anywhere I can find them?

1) .0056 mfd  125V 5% POLY
2) .0062 mfd  500V 5% POLY
 

Offline TimFox

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Re: capacitor replacement type
« Reply #1 on: July 18, 2020, 11:09:53 pm »
"Poly" is an insufficient description.  Do you mean polyester (polyethylene terephthalate or Mylar), polypropylene, polystyrene, polysulfone, or some other plastic film?
Polypropylene is a good choice, if you have the space, and can be had in 5% tolerance.  Polyester is a common choice for non-critical applications, but usually has a broader tolerance.
Try the search engine at a distributor, for example  https://www.mouser.com/Passive-Components/Capacitors/Film-Capacitors/_/N-9x371?P=1yznbzsZ1z0wppwZ1yx4atuZ1yzs9nv  for a 5.6 nF, 5% polypropylene capacitor.  You will have to choose a different working voltage:  what DC  voltage is actually present in the circuit?  If you don't know, then go higher.  Do not search with the obsolete term "mfd", since the modern meaning of "mfd" (millifarad) is 1000 times higher than what you want (microfarad).
« Last Edit: July 18, 2020, 11:14:54 pm by TimFox »
 

Offline bdunham7

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Re: capacitor replacement type
« Reply #2 on: July 18, 2020, 11:25:43 pm »
I'm looking for the following 2 capacitors but I'm unable to locate is there some other type I could use or anywhere I can find them?

1) .0056 mfd  125V 5% POLY
2) .0062 mfd  500V 5% POLY

It would help to know what they are for, but try looking for 5600pF and 6200pF (or thereabouts--in many applications a little more won't matter).
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline CramboneTopic starter

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Re: capacitor replacement type
« Reply #3 on: July 18, 2020, 11:47:02 pm »
They are for a Sencore TC162 tube tester
 

Offline H713

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Re: capacitor replacement type
« Reply #4 on: July 19, 2020, 05:22:27 am »
You might not find 125V and 500V parts, but you can probably find higher voltage rated parts. For 6.2 nF (same as .0062 mfd), Digikey only has 1.6 kV rated parts. That will be just fine. 5.6 nF they had 400V parts.

 

Offline floobydust

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Re: capacitor replacement type
« Reply #5 on: July 19, 2020, 06:13:33 am »
They look like polystyrene which are mostly gone nowadays. Mouser sells them as Xicon brand, but are low voltage 50V and 0.005uF or 0.0068uF offered.
In the Sencore TC162 Mighty Mite I see them for a neon lamp oscillator off 90VAC, guessing at least 160-250VDC parts are needed there.

Common are polypropylene high voltage film caps 1.25-2kVDC so they are a bit big. It depends on what can fit the lead spacing on your board.
Parts with long leads Panasonic ECWH series, consider Digi-Key Part Number   
P15430-ND, ECW-HA3C622H   CAP PP FILM 6,200pF 3% 1.6kVDC
P10479-ND, ECW-H12562JV   CAP PP FILM 5,600pF 5% 1.25kVDC 18mm with 15mm lead spacing and plump.

I think these could fit. The 50uF 50V electrolytic cap will surely need to be replaced as well.

edit: I see pics of another repair, the guy replaced the 0.01uF ceramic disc caps on the board.

Other hard to find parts https://www.justradios.com/
« Last Edit: July 19, 2020, 06:20:22 am by floobydust »
 

Offline H713

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Re: capacitor replacement type
« Reply #6 on: July 19, 2020, 09:46:53 am »
I hate to ask, but why are you replacing them? Poly caps rarely ever fail.

Lots of people go through and blindly "recap everything!!!11", and in many cases do more harm than good.
 
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Offline Gyro

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Re: capacitor replacement type
« Reply #7 on: July 19, 2020, 10:10:45 am »
They are for a Sencore TC162 tube tester

Polystyrene caps don't have any significant 'wear-out' modes, they are close tolerance and film and foil construction, so don't suffer loss of capacitance through self healing like metalized film ones.
« Last Edit: July 19, 2020, 12:11:50 pm by Gyro »
Best Regards, Chris
 
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Offline CramboneTopic starter

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Re: capacitor replacement type
« Reply #8 on: July 19, 2020, 12:41:11 pm »
The tester was given to me and they are missing from the board. I tested the transformer and it’s solid so I figured I would try to bring it back to life. All the resisters and diodes checked good. The R21 & R22 variables aren’t stock but seem ok.
 


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