My advise is this: Look up the RIFA parts you are replacing and then
use parametric search to find another vendor. RIFAs problem isn't wear
out from heating & cooling or "dry out". I left a fresh order of them
in their original packaging in a box in a climate controlled closet
(away from UV light) for a few years and when I opened it the
encapsulation had cracked. I believe the resin mix used is going
through an overly aggressive cure to keep the production line running
fast or something.
On Sun, May 25, 2025 at 6:54?PM bandrsn via groups.io
<bandrsn@...> wrote:
All,
Well, it finally happened - POP! - sizzle, sizzle. My fine 7104 blew its RIFA capacitor in a loud manner, and I know, I should have replaced it sooner.
I found what's left of the RIFA in the shielded power supply, but there's not enough of it left to get info from its case.
The downloaded service manual and schematics don't exactly match the B053423 S/N. The A23 Inverter Board shows two ceramic 0.02UF, 1400VDCAC capacitors in parallel (C1205 and C1206), both in series with a 27 Ohm resistor, R1205. My A23 board has (had) a single RIFA where R1205 was and what appears to be a jumper across one of the places for the capacitors.
My question is, what should the replacement RIFA be? Since the exploded one is in bits and pieces I can't get enough info from it to know.
The schematic shows the RIFA directly across the hot and neutral lines after the power switch.
Any brand/device values, etc. recommendations for a commonly available 115VAC replacement that, hopefully, will not explode again?
Also, the power supply construction makes it difficult to gain access to the back side of the Inverter Board. I was able to carefully snip away the bits of the RIFA plastic and foil, etc. so there are about 1/4" or slightly more of the tinned leads sticking out on the component side. I was planning to cut, bend and quickly solder to these exposed leads, being careful not to melt the solder too much on the other side and cause a short.
Does anyone foresee a problem with this if care is also taken to avoid any shorts, etc. on the component side too?
Thanks,
Bruce
AB6BA
