Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
Look for burned areas on the paper covering the power supply.
For more information on fixing it, here's the guy: http://maccaps.com/MacCaps/Repair_Service.html
This guide will work for you: [guide|21422]
'''UPDATE'''
OK, the video with sound was not up when I answered. That's the disk drive trying to read a disk. Hold the mouse button down when starting up to eject the disk. Then try another disk to see if it's the disk or the drive. If the disk will not eject, use a paper clip in the hole in the disk drive and manually eject it.
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It also appears to have a SCSI hard drive installed and that could also be your sound source, try unplugging it.
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It also appears to have a SCSI hard drive installed and that could also be your sound source, try unplugging the molex power connector to it.
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
Look for burned areas on the paper covering the power supply.
For more information on fixing it, here's the guy: http://maccaps.com/MacCaps/Repair_Service.html
This guide will work for you: [guide|21422]
+
'''UPDATE'''
+
OK, the video with sound was not up when I answered. That's the disk drive trying to read a disk. Hold the mouse button down when starting up to eject the disk. Then try another disk to see if it's the disk or the drive. If the disk will not eject, use a paper clip in the hole in the disk drive and manually eject it.
+
It also appears to have a SCSI hard drive installed and that could also be your sound source, try unplugging it.
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
+
Look for burned areas on the paper covering the power supply.
For more information on fixing it, here's the guy: http://maccaps.com/MacCaps/Repair_Service.html
This guide will work for you: [guide|21422]
+
'''UPDATE'''
+
OK, the video with sound was not up when I answered. That's the disk drive trying to read a disk. Hold the mouse button down when starting up to eject the disk. Then try another disk to see if it's the disk or the drive. If the disk will not eject, use a paper clip in the hole in the disk drive and manually eject it.
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
+
Look for burned areas on the paper covering the power supply.
+
For more information on fixing it, here's the guy: http://maccaps.com/MacCaps/Repair_Service.html
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
-
This guide will work for you: https://www.ifixit.com/Teardown/Macintosh+128K+Teardown/21422
+
For more information on fixing it, here's the guy: http://maccaps.com/MacCaps/Repair_Service.html
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.
+
This guide will work for you: https://www.ifixit.com/Teardown/Macintosh+128K+Teardown/21422
Bad capacitors will sometimes whistle. I would pull the cover off (to do this you will need a very long torx #15 ) (some come with a case spreader), and see if you can determine if the sound is coming from the power supply or the motherboard. If coming from the motherboard I would use a good light and look every capacitor over very carefully. Your looking for one that is bulging or bowed outwards and/or leaking.