It reads "No Disc" on all 6 settings - Emerson MS9700 CD Shelf System

How often was the player used? Four years is a typical lifespan of a cheap CD player section if it sees constant use. First, let's see if the player tries to read the disc. Load a disc and listen. Does the player make squealing noises or is it totally quiet? Squealing noises may indicate that the player is trying to synchronize with the disc but can't due to an obstruction on the lens or in the laser path inside the pickup or a defect in the pickup. This can also be caused by an intermittent signal problem due to a faulty ribbon cable. Totally silent means that the photo sensor is not getting any usable input from the laser at all, meaning that the pickup is "blind" for lack of a better word. This can be caused by an obstruction of the beam by foreign matter on the lens or inside the pickup all the way to a marginal or failed laser diode and/or photosensor array. This can also be caused by a bad ribbon cable with one or more severed traces. You could try to clean the optics. It would involve taking the cover off and finding a way to take a slightly damped swab and gently rub the objective lens on the pickup clean, followed by a drying with the dry side. But, unless the player is prone to dust accumulation (which was a big problem with quite a few Aiwa shelf systems with the 3 disc changers), cleaning it may not help. Another possibility could be that the transmission ribbon which connects the pickup to the player electronics may have developed breaks, which is another typical problem with many shelf systems. Yet another possibility, which is the worst case: the pickup may have worn out. Again, if the player is four years old and was used constantly, it is very possible that the pickup has decided to give up the ghost. Another possibility, which is EXTREME worst case and is not likely to happen at any time with any CD player is a failure of the CD decoder chip. The decoder chip handles the 8-14 demodulation and error correction of the CD signal and outputs the processed signal as PCM for upsampling and conversion. If this chip fails, the CD player will spin up and synch to the disc but, without decoding, the player will be unable to read the TOC and play the disc. But, as I said before, this usually never happens as the semiconductor parts are the most reliable components in a CD player and usually never fail unless they were deliberately damaged by an external influence, like shorting out one or more leads with a screwdriver while the player is powered. In the latter three events, replacement parts may not be easily sourced, if at all, and the required labor to effect the repair may not be worth it. (In addition, a new pickup has a protective solder short designed to protect the laser pickup from static discharge damage. This short has to be desoldered in order to allow the pickup to function.) In this case, replacement of the entire shelf system becomes necessary. If buying a new shelf system, stick with some of the better brands in this area like JVC, Sony, Panasonic, Aiwa, Pioneer, and even Philips. Brands to avoid include Sharp, Sanyo/Fisher, RCA, Emerson, and any cheap store brands like Durabrand or CurtisMathes. But, in general, even the finest shelf systems are a compromise in design which can affect reliability. Most, even from the recommended brands, weren't designed to be serviced very easily when they break as people usually dispose of them rather than have them repaired.