CJ said:Mallory made some green caps
Tubetec said:Just a quick question for those in the know ,
Sometimes I pull apart old bits of electronic gear containing what looks like paper in oil caps ,these are mounted in a cardboard tube and wax dipped . Almost all of them show very poorly for leakage ,would gentle baking and then re dipping in wax bring these back to life ,could be moisture ingress thats made em go bad .
Reforming old caps is just a matter of slowly charging them up through a high impedance the limits the inrush current to prevent releasing smoke. Of course if they never charge up to full rated voltage after a decent interval, trash them.Tubetec said:Come to think of it many paper in oils in the old days used contain PCB's and a wax seal on an oil impregnated cap is going to be a waste of time anyway, so I think your right there MJ.
I really dont fancy heating those things up in my oven where I cook food at any rate ,maybe on a radiator or heater of some kind
I dont know what the cause of the breakdown could be Shab,is it possible the foils may have oxidised and damaged the dielectric ,I guess even at a modest heat for some hours if its starts to show an improvement in leakage resistance it might be worth continuing ,could Rf be used to heat the cap from within to drive out the moisture while its still soldered in an old radio ,or maybe that would be a good way to kill it off completely ,I dont know .
Has anyone tried reforming electrolytics ,I've heard about it but Ive never tried it ,I guess you have to be selective and not be bothered with anything showing signs of damaged seals or with stuff spueing out of them . It weird cause some electros say in the psu of old valve radios can still be working after 50-60 or more years .
Tubetec said:It weird cause some electros say in the psu of old valve radios can still be working after 50-60 or more years .
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