I am trying to repair/refurbish an old Farnell L30d power supply, 0 - 30v and current limiting to 2 amps. There are two caps inside, one of which has blown. The caps are Hunts 3132A. Hunts no longer exist. I have a circuit diagram for the ps and it shows these caps are 2200nf 63v high ripple.

Can I just replace the caps, with any old modern 2200nf 63v electrolytic caps? The ones I have found on eBay are considerably small tha the ones fitted, so is it just a case of securely mounting the new ones? They are connected in parallel.

  • 1
    \$\begingroup\$ Do you really mean 2200nF == 2.2µF? If yes, I wouldn't bother with electrolytic caps at all but use PP ones. \$\endgroup\$
    – Janka
    Feb 16 '18 at 15:15
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    \$\begingroup\$ A picture speaks a thousand words. \$\endgroup\$
    – Andy aka
    Feb 16 '18 at 15:18
  • \$\begingroup\$ And if you actually meant 2200uF 63V, then get any good quality modern equivalent. Just avoid dubious suppliers or the new capacitors won't last long. \$\endgroup\$
    – Simon B
    Feb 16 '18 at 15:24
  • \$\begingroup\$ Does the circuit diagram that you have happen to have a note near the bottom left stating "ALL CAPACITOR VALUES IN μF" like the one linked to on Farnell L30 Stabilised Voltage Supply 1963 Germanium? \$\endgroup\$ Feb 16 '18 at 16:23
  • \$\begingroup\$ Andrew, thank you. Yes, I did mean 2200uf and 63 volts. The link does show the ps, but it is later than that, not germanium, it is the section later, which h starts "from about 1969" all silicon, I believe. I think that is also where I got the manual and diagram from. \$\endgroup\$
    – Rob Manser
    Feb 16 '18 at 18:06

Assuming the actual value of the capacitors is 2200uF, any modern electrolytic of the same physical size and value from a reputable company should work. Make sure it's rated for at least 63V, more is ok. Slightly higher capacitance may be ok, but we would need to see the circuit diagram to confirm this. Try to find caps from Panasonic, EPCOS, Nichicon, Rubycon, or Nippon-Chemicon. They are some of the most reputable capacitor manufacturers out there.

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    \$\begingroup\$ It is certainly 2200uf my mistake. As above, I think that is where the circuit diagram is. I have looked around for suitable caps already, but there is nothing remotely near the same physical size. These are about 75mm long, by about 40mm dia. I guess that's how much things have changed. Should I mount them on some heats ink? \$\endgroup\$
    – Rob Manser
    Feb 16 '18 at 18:20
  • \$\begingroup\$ As long as you can get a capacitor with a similar pin spacing and narrower body (less than 40mm), it should work. What is the lead spacing of the original capacitor? Can you post a photo? You should not need a heat sink for a capacitor. \$\endgroup\$
    – DerStrom8
    Feb 16 '18 at 18:43
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    \$\begingroup\$ And even if you can't get the same pin spacing, just by leaded capacitors - radial or axial - and bend the leads to fit. No need for heatsinks. \$\endgroup\$
    – Simon B
    Feb 16 '18 at 20:15

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