From leaking batteries to bad capacitors, Mac LC 520s require maintenance to remain in good working order. Read below to find out about what issues may need addressing.
The Mac LC 520 has many surface-mount (SMD) electrolytic capacitors on its logic board. These capacitors have a near 100% failure rate and will leak a corrosive and conductive electolyte fluid over the board that will damage components and traces given enough time. These capacitors must be replaced for continued operation of any Mac LC 475. Capacitor reference information is available under the resources page, or directly through The Capacitor Reference Library.
The LC 520's analog board/power supply can also often need recapping.
The LC 520 uses a 1/2AA size Lithium battery for backing up the computer's PRAM. The original 30+ year old batteries are prone to leaking severely in their age and need to be removed immediately from any LC 520.
The LC 520's case is now extremely brittle. These will not, and I repeat will not survive shipping. You can add all the packing material that you want, but I have yet to hear of a single case in recent years of one of these arriving intact when shipped. If you are looking to purchase one, do it locally.
When disassembling, use extreme care with all parts. Any parts that are clipped in place should be hit with a hair dryer first to soften up the plastic a bit, or they will break.
Nearly all of these have also turned yellow to some extent. For those cases, a retrobrite process can restore them to the proper color.
Many original SCSI hard drives for these have gone bad, especially those made by Quantum, which suffer from sticky rubber bumpers in the head assembly.
The floppy drives in these often suffer from eject motor failures due to a gear that falls apart with age. This gear can be replaced without too much trouble. They also suck in tons of dust, so a good cleaning is in order for just about any unserviced unit.
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