Of all these, recap seems to be the most debated. Some swear that no values should change, some that everything should change, can we at least agree on the terms?
A short bio: I built my first circuits from kits in the late '60s / early '70s: first an Eico "light organ" then an Eico oscilloscope (round CRT, single-trace recurrent trace), was always a stereo-head and spent much of my teens in a local high-end stereo shop (Pioneer, Marantz, Kenwood, McIntosh, Philips, Dual, JBL, Advent, et al), worked as a Tech for a stereo shop during college, electronics Design Engineer (R&D and high-volume production) for much of my career. Today I enjoy the hobby of collecting, listening to, servicing and restoring stereo equipment both vintage and new.
The concept of recap is the most ambiguous to me as it seems to involve replacing some of the capacitors in older equipment under the assumption that the existing capacitors are bad. It is a term often perverted by those who buy and sell to get a higher price, I even see a shop in Ann Arbor that claims to "re-rate" the output of his "serviced" Marantz products at a higher output because he has added additional capacitors to the power supply filters. This is to me neither a restoration nor a recap, it is a modification.
Recap to me means replacing all suspect capacitors (usually this includes all electrolytic and tantalum in older equipment) with the same rating new parts, period.
Restoration (electronic) to me means a recap, and adding replacement of all suspect semiconductors (those known to have problems) with like-specification new, and testing all remaining, testing many critical resistors and replacing as needed, testing and replacing diodes as needed, cleaning and replacing all thermal paste (or pads), checking all solder, a thorough cleaning including cleaning and lubricating potentiometers and switches as needed (some contacts should remain dry, some are designed to have lubrication), and replacing relays. In some units this also includes light-bulb replacement and velum replacement. Then all voltages etc. are checked and adjusted, any calibrations made. Any Factory Service Bulletins should be part of this restoration.
Servicing is harder to define but is at least a thorough cleaning of switches and pots, removal of dust and dirt in the unit, repair of anything not performing as new (need test equipment for this), adjustment and calibration, and addressing any FSBs.
Modification is anything deviating from the original spec. In most older equipment the original spec parts are not all available and substitutions need to be made and I'd categorize necessary (by availability) minor and calculated substitutions as restoration. Substantial changes or the common "bigger is better in caps" is to me a modification.
A short bio: I built my first circuits from kits in the late '60s / early '70s: first an Eico "light organ" then an Eico oscilloscope (round CRT, single-trace recurrent trace), was always a stereo-head and spent much of my teens in a local high-end stereo shop (Pioneer, Marantz, Kenwood, McIntosh, Philips, Dual, JBL, Advent, et al), worked as a Tech for a stereo shop during college, electronics Design Engineer (R&D and high-volume production) for much of my career. Today I enjoy the hobby of collecting, listening to, servicing and restoring stereo equipment both vintage and new.
The concept of recap is the most ambiguous to me as it seems to involve replacing some of the capacitors in older equipment under the assumption that the existing capacitors are bad. It is a term often perverted by those who buy and sell to get a higher price, I even see a shop in Ann Arbor that claims to "re-rate" the output of his "serviced" Marantz products at a higher output because he has added additional capacitors to the power supply filters. This is to me neither a restoration nor a recap, it is a modification.
Recap to me means replacing all suspect capacitors (usually this includes all electrolytic and tantalum in older equipment) with the same rating new parts, period.
Restoration (electronic) to me means a recap, and adding replacement of all suspect semiconductors (those known to have problems) with like-specification new, and testing all remaining, testing many critical resistors and replacing as needed, testing and replacing diodes as needed, cleaning and replacing all thermal paste (or pads), checking all solder, a thorough cleaning including cleaning and lubricating potentiometers and switches as needed (some contacts should remain dry, some are designed to have lubrication), and replacing relays. In some units this also includes light-bulb replacement and velum replacement. Then all voltages etc. are checked and adjusted, any calibrations made. Any Factory Service Bulletins should be part of this restoration.
Servicing is harder to define but is at least a thorough cleaning of switches and pots, removal of dust and dirt in the unit, repair of anything not performing as new (need test equipment for this), adjustment and calibration, and addressing any FSBs.
Modification is anything deviating from the original spec. In most older equipment the original spec parts are not all available and substitutions need to be made and I'd categorize necessary (by availability) minor and calculated substitutions as restoration. Substantial changes or the common "bigger is better in caps" is to me a modification.
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