UPDATE:
Today I've tried more to fix the mac.
Firstly, I checked the voltage and current going to the drive. The currents are as expected, but the voltages are not. The 5V supply is fine, but, at the point where the drive shuts down, the 12V supply begins to rise (strange as the main PSU doesn't even supply more). If, however, I measure it under no load, it stays at 12V (i.e. it's not rising because of the current drop). Strangly, the drive continues to draw from the 5V supply even when it has stopped.
Secondly, I discovered a very strange thing. When starting up, the speaker emits a very quiet whistling noise, a bit like a jet plane. At first, it rises, then it wobbles a bit in pitch, then, at the point when the drive would have shut down (although the noise is there even without the drive), it starts to slowly lower in pitch, but seems to always remain present.
Are the two issues related or not? And what is causing the 12V supply to rise in voltage?
Please help; don't abandon my topic
.
Today I've tried more to fix the mac.
Firstly, I checked the voltage and current going to the drive. The currents are as expected, but the voltages are not. The 5V supply is fine, but, at the point where the drive shuts down, the 12V supply begins to rise (strange as the main PSU doesn't even supply more). If, however, I measure it under no load, it stays at 12V (i.e. it's not rising because of the current drop). Strangly, the drive continues to draw from the 5V supply even when it has stopped.
Secondly, I discovered a very strange thing. When starting up, the speaker emits a very quiet whistling noise, a bit like a jet plane. At first, it rises, then it wobbles a bit in pitch, then, at the point when the drive would have shut down (although the noise is there even without the drive), it starts to slowly lower in pitch, but seems to always remain present.
Are the two issues related or not? And what is causing the 12V supply to rise in voltage?
Please help; don't abandon my topic
.