Is it the TRANSPORT (drawer won't open/close properly)
OR
Is it a LASER problem (they get weak, unable to read the disc)
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If Laser
I bought a used Oppo BDP-83, arrived with "Unknown Disc" repeatedly. Tech diagnosed: "It's the Laser". Oh, now a bit of research, lots of comments about Lasers going bad. Found this:
https://www.ebay.com/itm/Blue-ray-Laser-Head-OPPO-BDP-83-Cambridge-AZUR-650BD-For-KEM-430AAB-Accesso...Returned for full credit including shipping cost.
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No precision needed for replacement, just a screwdriver and steady hand to remove/replace the ribbon cable and a few snap connectors.
It's sandwiched in between layers, various players have more or less layers, but ANY computer or electronics, or handyman can change them.
The Oppo BDP-83 (I imagine others) assembly mounts on springs, simply tighten/loosen the two front screws raises/lowers the front of the transport to open/close thru the faceplate's mouth without hitting anything.
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Bought an Oppo BDP-105. Checked first, too many people sell the laser, it clearly fails eventually.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=bdp-105+laser&...I insisted on a low-mileage Laser, found one.