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Main => Everything Else => Topic started by: BadMouth on July 16, 2016, 01:32:04 pm

Title: Need help finding a capacitor or substitute
Post by: BadMouth on July 16, 2016, 01:32:04 pm
Fumbling my way through another attempted tv repair for a friend (I'm 2 for 2 so far!).
I have some burned up blue round ceramic disc capacitors that I can't seem to find a replacement for.
(have checked digikey, mouser, ebay, etc.)  Came across other message board posts about not being able to find them, but no substitutions.

They are 54pF 6Kv.

From what I can tell, these just provide some extra oomph to turn the backlight on.
Looks like this has happened over time.  The one for the bottom light looks burnt, the one for the upper light is just lightly toasted.

Can I get away with just using one with more capacitance or running two 27pF caps in parallel?
How much bigger could I go.  Having trouble finding anything even comparable to 54pF.

Title: Re: Need help finding a capacitor or substitute
Post by: ed12 on July 16, 2016, 01:50:10 pm
as you are basicly  working in the (tube light switcher) (hv) supply
the rule of thumb is easy
6kv is the important part >no less<
54pf makes it a high freq switcher
so basicly  68pf (higher freq or 52pf a little lower freq should get u into the game
just rem 6kv or a tad higher 9-10kv is the norm now

ed
Title: Re: Need help finding a capacitor or substitute
Post by: BadMouth on July 16, 2016, 03:34:33 pm
Quote from: ed12 on July 16, 2016, 01:50:10 pm
as you are basicly  working in the (tube light switcher) (hv) supply
the rule of thumb is easy
6kv is the important part >no less<
54pf makes it a high freq switcher
so basicly  68pf (higher freq or 52pf a little lower freq should get u into the game
just rem 6kv or a tad higher 9-10kv is the norm now

ed

Thanks man!  :cheers:

I ordered some 56pF 6.3kv from Digi-Key (shipping was a tad cheaper than mouser).
It's going to feel pretty good if I can fix this tv with $1.28 worth of parts.  ;D
(I did order double what I needed in case I mess one up or something)
Title: Re: Need help finding a capacitor or substitute
Post by: ed12 on July 16, 2016, 03:45:52 pm
yup they should do u just fine.:)
also well u are into google
search for cft  yes cft not crt tube tester..i built 1 never looked back
great for testing lcd tube lights


ed

thought I would clear the term up

Cold cathode

form  >https://en.wikipedia.org/wiki/Cold_cathode<

also here >ccfl tester schematic<
go to badcaps reg if u are not

enjoy
Title: Re: Need help finding a capacitor or substitute
Post by: Howard_Casto on July 16, 2016, 06:32:24 pm
Note to noobs:  cft=compact fluorescent tube... aka a modern fluorescent bulb like those commonly used to back-light tvs.   
Title: Re: Need help finding a capacitor or substitute
Post by: BadMouth on July 20, 2016, 06:48:28 pm
TV seems fixed.  I'm 3 for 3 now. 
Thanks again Ed.

(http://uploads.tapatalk-cdn.com/20160720/46618e9d2cd2a56db7bb2b2642e6c24d.jpg)