Weird wear marks on HiMD discs

[dex Otaku]

I occasionally leave my discs sitting on my desk out of their sleeves. Yes, naughty me.

I also occasionally slide the protective cover back and blow any dust that may be on the disc surface out.

Tonight I did so, having left both of the HiMD 1GB discs I have out. I noticed wear marks on the one that I bought not long ago, which has only been written to about 6 times, and hasn't been played that often. [For regular listening I use MD80s, reserving the 1GB discs for location recording purposes.]

I decided to check the other disc which I have been using repeatedly since August of 2004. It also shows wear marks, but they aren't as pronounced as on the newer one.

The wear marks are on the top of the discs [the side accessed my the magnetic head]. They are in perfect rings as though the discs had been placed in a recorder with a damaged or improperly-gapped head.

On the older disc, the marks are spread across the top surface. They do not look threatening, per se. The disc also shows marks all the way around the outer edge on both top and bottom surfaces, as though it had been spinning while wet. Since I have used that disc in high-humidity situations, I don't find that entirely surprising.

The the newer disc, the marks are confined to a single ring halfway between the inner and outer edges of the writeable surface. They are noticeable enough that i would actually call them scratches. It almost looks as though the disc had been left in a unit with a faulty magnetic head, on pause, for at least several days straight.

I have 4 MD80s that I regularly use for making shorter PCM recordings on location. These discs actually get used far more often than either of the 1GB ones. I compared these [sony Neige and Sony "Premium Gold" MD80s, including two I have been using repeatedly and with at least 3 MD recorders other than my own 2 since 2002] with the 1GB discs; there are no wear marks on their top surfaces whatsoever. I have also compared against several MD80s that I use for downloading music onto for portable listening on a regular basis. Again, there are no marks on their top surfaces at all.

I must state that neither of my 1GB discs have ever shown problems such as write errors [that were not caused by the recorder being bumped, dropped, or otherwise disturbed while recording] or read errors. In fact, I've never had any problems with either disc that would suggest they are physically defective in any way.

Still, I find these wear marks worrisome. The fact that the newer disc shows significant wear despite having been seldom used, along with my MD80s being completely unmarked despite being used regularly [and in fact, more often] in exactly the same equipment suggests that the disc was already worn when I purchased it.

Does anyone else find this strange? Do anyone else's discs show the same kind of wear?

[btw - the older disc came with my NH700 in a factory-sealed plastic package from MD-Canada; the newer one came from the local Futureshop in Sony's shrink-wrap.]

[greenmachine]

I've noticed these as well on one (the one that came with my used unit) of my four 1GB HiMDs (the other three, which i bought new don't show these marks), as well as on some (maybe one of four) of the standard discs, more often on non-Sony brands. On some MDs you can even hear the scratching noise while recording. It scares me and i hesitete to record on these particular discs. I bought a great part of my standard MDs used and don't know what happened to them beforehand, maybe they were stored in a car, got too hot and deformed? Is it harmful to the magnetic head?

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[pauljones52]

I've experienced a similar problem with a few normal minidscs. It tends to occur around the 60-70min mark on the underside of the disc in a small circular ring. I put it down to bad storage of my minidiscs, however it is odd how it always occurs in roughtly the same place on the disc (for me anyway). 2 of the discs this has occurred on has resulted in a inability to rewrite the discs at these sectors.

[Sony_Fan]

I've experienced a similar problem with a few normal minidscs. It tends to occur around the 60-70min mark on the underside of the disc in a small circular ring. I put it down to bad storage of my minidiscs, however it is odd how it always occurs in roughtly the same place on the disc (for me anyway). 2 of the discs this has occurred on has resulted in a inability to rewrite the discs at these sectors.

The same marks would show up when I would record with my old MD unit. I think it's normal and it shouldn't affect recordability. I've used my old standard MDs on my RH10 and have not noticed any problems. I wouldn't worry about it too much. There's a clear coat like substance above the actual recording surface, so it's protected, unless it's scratched deep. Basically, I believe the marks show how much of the disc has been used or where the recording has overwritten something else.

Edited March 1, 2006 by Chris G