Hi everyone,
There actually was a time when early SMPS and late bakelite housed electrolytic caps coexisted in high end industrial gear. A friend of mine just got himself a CNC milling machine form that time with its first set of now 41 year old caps still installed in the PSU... and it's malfunctioning.
Two of the caps have already leaked slightly onto the board. I have not desoldered or measured any so far but they should qualify for replacement.
Now I'm wondering what to put in there as a replacement. First idea was state of the art low-ESR Nippon KY, LXZ or Panasonic FR. After all it's an SMPS.
But then again it's an ancient SMPS and some folks say that super low ESR is not always the best choice for ancient gear as it may be designed expecting a certain resistance in the caps to limit current spikes. The original Siemens EK caps are probably the same as Roederstein EK but I have no idea what their properties may have been when new.
So another idea would be using something more general purpose like Panasonic EB.
What caps would you use in such a PSU?
There actually was a time when early SMPS and late bakelite housed electrolytic caps coexisted in high end industrial gear. A friend of mine just got himself a CNC milling machine form that time with its first set of now 41 year old caps still installed in the PSU... and it's malfunctioning.
Two of the caps have already leaked slightly onto the board. I have not desoldered or measured any so far but they should qualify for replacement.
Now I'm wondering what to put in there as a replacement. First idea was state of the art low-ESR Nippon KY, LXZ or Panasonic FR. After all it's an SMPS.
But then again it's an ancient SMPS and some folks say that super low ESR is not always the best choice for ancient gear as it may be designed expecting a certain resistance in the caps to limit current spikes. The original Siemens EK caps are probably the same as Roederstein EK but I have no idea what their properties may have been when new.
So another idea would be using something more general purpose like Panasonic EB.
What caps would you use in such a PSU?
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