I was excited to recently find an LC 550 motherboard for cheap, allowing me to upgrade my pokey 16 MHz/16-bit-bus Color Classic to a 33 MHz/32-bit-bus Color Classic II -- and the holes in the backplate still line up.
However, when I have the board in, there's an irritating high-pitched whine from the speaker. It isn't on for a couple of seconds during power up, but then it cuts in -- it appears to be related to the display. In fact, if I change the resolution of the display (you can set 560x384 if you have an Apple IIe card), the pitch of the whine changes. Likewise, if I let the screen turn off (from the Screen control panel), the whine goes away. When I use the original board, no whine. Does anyone have any idea what might be causing this, or what might be able to be done about it, if anything? Is it likely to be my particular board, or something that's going to happen with any 550 board? Thanks for any thoughts. -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/
