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12-17-2018, 10:45 PM
Hi Noel
The service life for an electrolytic is generally regarded to be about fourteen years maximum, based on the changes of dielectric absorption (DA) and dissipation factor (DF). This is regardless of whether the cap is long-life and/or is operated at much reduced temperature and/or how the life calculation might come out, with a result longer than fourteen years.
Apart from that, as you describe these amps are not easy to work on - a "fix" might result in a few "breaks" that then need fixing themselves. So it is a tough decision. The old adage "if it ain't broke don't fix it" seems to apply, but if the unit fails soon after you've repaired it, the customer will think you did a poor job regardless of the fact that a completely different thing failed each time.
If the amp is played regularly then the caps will remain functional for decades even with astronomical DA or DF. The mechanical integrity to the board is important if these are axial-lead.
Note that the removal of a component from the board should be done in a manner that saves the board rather than the component - unless the part is extremely expensive or cannot be obtained or substituted. Always ADD fresh solder and remove the component with live heat THEN clear the holes. Trying to clear the holes first results in far more heat being used and potential lifting of traces or pads. ALWAYS ADD fresh solder when you are doing the solder removal step with a solder sucker or wick.
I'm not sure if any of this helps with your decision? But everyone should heed the advice of the "note".
The service life for an electrolytic is generally regarded to be about fourteen years maximum, based on the changes of dielectric absorption (DA) and dissipation factor (DF). This is regardless of whether the cap is long-life and/or is operated at much reduced temperature and/or how the life calculation might come out, with a result longer than fourteen years.
Apart from that, as you describe these amps are not easy to work on - a "fix" might result in a few "breaks" that then need fixing themselves. So it is a tough decision. The old adage "if it ain't broke don't fix it" seems to apply, but if the unit fails soon after you've repaired it, the customer will think you did a poor job regardless of the fact that a completely different thing failed each time.
If the amp is played regularly then the caps will remain functional for decades even with astronomical DA or DF. The mechanical integrity to the board is important if these are axial-lead.
Note that the removal of a component from the board should be done in a manner that saves the board rather than the component - unless the part is extremely expensive or cannot be obtained or substituted. Always ADD fresh solder and remove the component with live heat THEN clear the holes. Trying to clear the holes first results in far more heat being used and potential lifting of traces or pads. ALWAYS ADD fresh solder when you are doing the solder removal step with a solder sucker or wick.
I'm not sure if any of this helps with your decision? But everyone should heed the advice of the "note".
