I've noticed occasional screen interference when the hard drive is accessed on a Classic II. The cables are connected securely and I'm assuming the problem is with the analog board. If so, what do I need to examine/replace on the board?
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Hard Drive Interference on Classic II
- Thread starter Scott Baret
- Start date
Checking the supply voltage is certainly a good recommendation. You may discover that the voltages are fine, however. If that's what you find, note that a not-uncommon source of the symptoms you describe is magnetic in origin. The magnetic fields emanating from the drive can easily perturb the electron beam, causing the raster to execute a characteristic hula dance. If that turns out to be the problem, your options are limited. Either reorient the drive (difficult), replace the drive with one whose fields are weaker or oriented differently (a crapshoot), or live with it.
What kind of interferince?
I get a feeling it's magnetic based on what was mentioned. I tried the analog board in another Classic with a different hard drive (I've got a non-Apple ProDrive LPS in the Classic II).
As for what the interference is, it's just a very minor twitch of the screen when the drive is accessed sometimes. It's really not all that noticeable (only when the drive is being accessed all the time) so I think I'll just live with it. However, I will test the voltages sometime soon just to make sure (this is not high on my priority list since the board worked fine in the other Classic but I'd like to see what it is anyways just so I can rule out all possible causes--we all know how quirky this older hardware can be).
As for what the interference is, it's just a very minor twitch of the screen when the drive is accessed sometimes. It's really not all that noticeable (only when the drive is being accessed all the time) so I think I'll just live with it. However, I will test the voltages sometime soon just to make sure (this is not high on my priority list since the board worked fine in the other Classic but I'd like to see what it is anyways just so I can rule out all possible causes--we all know how quirky this older hardware can be).
