I'm getting some transient disc reading errors and I want to verify that it's actually the laser before I do any pot tweaking.

- Disc reading errors are typical: it either fails to load at start, quits loading after the Sega logo, or eventually crashes after playing for some time.

- The errors do not happen consistently. No games are affected worse than any others. I also tend to get a run of errors followed by a period of no errors at all. Length of time playing a game doesn't seem to correlate to whether it will start having read errors or not

- Just as an example, I've had Shenmue crash twice about fifteen minutes into the game. I've had it start to deteriorate w.r.t load times after about hlf an hours once. I've also played it several times for at least an hour at a time with no deterioration at all.

- The DREs aren't THAT common, but they're frequent enough to be troubling.

- I have noticed that manually pushing the laser up and down the worm gear a few times does resolve the issue temporarily. Disassembling the GD-ROM assembly and putting it back together without doing anything else, or with just cleaning the gears and nothing else, does too, which is something making me think it might be a mechanical problem or something with the ribbons, and not the laser itself.

- The GD-ROM spindle appears to be spinning quite fast, although I don't know how fast they're supposed to spin. Might this indicate that the resistance to the laser is too low? I was under the impression that GD-ROMs need to be spun slower to read properly.

- The drive unit made a noisy, but lower-pitched, somewhat grindy sound initially. After cleaning off all residual and new lubrication, the sound's taken on a considerably higher pitch. Dreamcasts are noisy, but what's the usual timbre of GD-ROM motor noise?

- It's a Rev. 2 system.

- I only use GD-ROMs in the system, so I can't tell you if it would read CD-ROMs better or worse.

- I found a set of Reader Calibration Disc isos for the Dreamcast online. Can I use those to determine how well the laser is working, and as a guideline for pot tweaking, if my focus is on actual GD-ROMs, or are those calibration isos intended for tweaking towards playing CD-Rs?

So. Pot tweak? Replace the ribbon cables? Lubricate the worm gear with silicon/white lithium grease? Something else?

Is it safe to run it without any lubrication for a bit to see if I still get read errors, or is the risk of messing up the little plastic nubby gripping the worm gear too high?

(If I do need to pot tweak, I have to get a multimeter anyway since I have some corrosion on my XBox's motherboard that needs dealt with. Good times).