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| 44 year old electrolytic capacitor as good as new |
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| VK3DRB:
--- Quote from: Zero999 on March 06, 2020, 09:13:02 am ---You only measured the capacitance. What's the ESR? --- End quote --- ESR measured at 0.12 ohms. Not bad for its age. |
| amyk:
In my experience, leaky capacitors will often read high on a meter. How much leakage current does it have at 5V? --- Quote from: bd139 on March 06, 2020, 12:04:09 pm ---I wouldn't trust the ESR either necessarily. I recently repaired something which the capacitors were pissing out electrolyte but the ESR and capacitance were fine. --- End quote --- You won't see any change until the plates start drying. Maybe they were very full of electrolyte. |
| all_repair:
--- Quote from: VK3DRB on March 06, 2020, 12:20:56 pm --- --- Quote from: Zero999 on March 06, 2020, 09:13:02 am ---You only measured the capacitance. What's the ESR? --- End quote --- ESR measured at 0.12 ohms. Not bad for its age. --- End quote --- These well made capacitors most probably can go on for additional 5 year or more, where newly made capacitors with all kind of cost cutting likely last for only 2 years. |
| all_repair:
--- Quote from: bd139 on March 06, 2020, 12:04:09 pm ---I wouldn't trust the ESR either necessarily. I recently repaired something which the capacitors were pissing out electrolyte but the ESR and capacitance were fine. --- End quote --- A good capacitor tester should include a "stink" indicator. Many time the leak is just at the base, and you have to see closely through the seam between the capacitor base and the PCB, or place your nose close for detection. |
| rsjsouza:
I also have very ancient capacitors that are still relatively in spec but, as others have said, other parameters will tell how good a capacitor still is. The dissipation factor (which ESR is one of its components) and leakage will be the measurable specs. My largest capacitor is a Siemens 75mF / 25V and it was manufactured in 1980. It currently shows ~82mF and its leakage hovers around 2mA. The oldest still in good shape fits my 50 year old Power Designs 5015A. The absolute oldest ones are a Philips populating a 1946 Radio (Philips BX462A) and two Teslas from the 1950s. All of them are shot (awaiting time for the equipments to be restored). In my experience, all "Computer-grade" capacitors are the all-time kings of longevity. |
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