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#1 |
Shock Therapist
Join Date: Sep 2016
City & State: Victorville, CA
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 338
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![]() I would like to re-purpose the transformer from this 2013 MacBook Pro power supply, but I can't seem to locate the specific transformer they used in this power supply, and therefore I don't know how the terminals should be connected. I'm assuming that it converts AC down to 24 volts, but the last time I attempted to connect a salvaged transformer from which I could not locate its datasheet, I let the smoke out...
Here is a photo of the board. If the bottom image were slid upward it would overlay the top image and the pins of all components would match up. I also labeled the pins of the transformer so that when we discuss it, we can reference the pins accurately. ![]() What I am trying to find out, is which pins can I connect to 120 so that I can measure the other side of the transformer and determine what the output voltage is? Thank you for any input you can provide,
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#2 |
Badcaps Veteran
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 4,873
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![]() This is a high frequency switching transformer. It is not ment to be connected to 120vac. It likely operates at 20~100KHz
Pins 3&4 are likely the primary, 5&6 are feedback/run voltage and 1&2 are the secondary output If you connect it to 120vac 60hz you will destroy it. Read about switch mode power supplies Last edited by R_J; 11-04-2019 at 06:05 PM.. |
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#3 | |
Shock Therapist
Join Date: Sep 2016
City & State: Victorville, CA
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 338
|
![]() Quote:
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#4 |
Badcaps Veteran
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 2,889
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![]() The topology for that adapter is discontinuous flyback (the seeming lack of an output inductor is the big clue). That means that the main "transformer" is actually a coupled inductor. When switch Q1 is on, it charges the inductor. When Q1 is turned off, the energy stored in the inductor discharges into the output circuit. Those two devices on the output side you labelled "MOSFET" are probably rectifiers.
Not only is the "transformer" unsuitable for connection to 60Hz power, the core is gapped, probably with a spacer. That gap is what makes the part an inductor, and energy is stored in that gap. You probably can only use that "transformer" as a replacement part in a more or less identical circuit.
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PeteS in CA Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells. Where might is right There is no right. - Sophocles in "Antigone" **************************** All that is gold does not glitter, Not all those who wander are lost; - J.R.R. Tolkien, The Fellowship of the Ring **************************** To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it. Last edited by PeteS in CA; 11-07-2019 at 04:23 PM.. |
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