I recently acquired an Apple IIe manufactured in 1985. Expecting to need replace the RIFA caps in the power supply as to prevent the notorious puff of smoke, I opened up the DynaComp (606-5001) power supply and found WIMA MKS-4 caps instead of RIFA caps. These capacitors are encapsulated in solid red potting instead of the translucent yellow RIFA potting.
I haven't been able to find any mentions of WIMA branded capacitors being used in these power supplies and there is no indication that this power supply had been worked on (one of the screws holding in the PS was pretty well fused to the bottom of the case). I suppose it is possible some manufacturing runs simply used what they had available.
So I am wondering if anyone else has come across these in Apple IIe power supplies and if they have a better or worse reputation compared with RIFA caps. From my understanding the failure point with RIFAs were the epoxy they used for encapsulation was prone to cracking which compromised the component exposing it to air/humidity. The solid red epoxy on the WIMA caps in my power supply look pristine and everything is currently working fine.
I haven't been able to find any mentions of WIMA branded capacitors being used in these power supplies and there is no indication that this power supply had been worked on (one of the screws holding in the PS was pretty well fused to the bottom of the case). I suppose it is possible some manufacturing runs simply used what they had available.
So I am wondering if anyone else has come across these in Apple IIe power supplies and if they have a better or worse reputation compared with RIFA caps. From my understanding the failure point with RIFAs were the epoxy they used for encapsulation was prone to cracking which compromised the component exposing it to air/humidity. The solid red epoxy on the WIMA caps in my power supply look pristine and everything is currently working fine.
