iMac G4 Power Supply Component B1

[lfletche]

Hey All, hoping someone can help point me in the right direction. I'm working on a later revision iMac G4 that has a dead power supply. This is one of the later "USB 2.0" 1Ghz revisions and it has a Samsung power supply unit in it with model number: PSCF161101A.

The first thing I noticed was the fuse had blown on this power supply.... digging around further I found it's had a rather catastrophic failure up around the bridge rectifier (D1) with one of the legs on that completely melted away - see the pics. My working theory with this is the fault was either that D1 rectifier or a nearby component which looks like a diode labeled B1. The issue is when I look at that component I can't see any text on it and I am struggling to find any references to what that part actually is. The component itself if it is a diode is stuffed as it's letting voltage through both ways. I've been able to work out all the replacement parts for everything else nearby - except this B1 component.

Hoping someone has tried a repair on one of these before and may have an idea or reference on this component? Thanks for any help in advance!

Cheers,
Luke.

 

[Michael_b]

Hey All, hoping someone can help point me in the right direction. I'm working on a later revision iMac G4 that has a dead power supply. This is one of the later "USB 2.0" 1Ghz revisions and it has a Samsung power supply unit in it with model number: PSCF161101A.

The first thing I noticed was the fuse had blown on this power supply.... digging around further I found it's had a rather catastrophic failure up around the bridge rectifier (D1) with one of the legs on that completely melted away - see the pics. My working theory with this is the fault was either that D1 rectifier or a nearby component which looks like a diode labeled B1. The issue is when I look at that component I can't see any text on it and I am struggling to find any references to what that part actually is. The component itself if it is a diode is stuffed as it's letting voltage through both ways. I've been able to work out all the replacement parts for everything else nearby - except this B1 component.

Hoping someone has tried a repair on one of these before and may have an idea or reference on this component? Thanks for any help in advance!

Cheers,
Luke.

I have a G4 which *might* have the same power supply. I could check to see if there’s any legible marks on mine, if that’d be helpful.

 

[lfletche]

Hey @Michael_b - if you do and you could that would be extremely helpful and greatly appreciated!

As I understand it, it is the USB2.0 models that have this power supply - You can tell by looking at the screen of the iMac - the word “iMac” is written in the newer font (Myraid?) rather than the older Apple Garamond font.

The diode is sandwiched between two capacitors so requires some degree of dismantling of the power supply itself. If you’re willing to do that as I said it would be greatly appreciated.