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Resistance to GND on PPBUS is 25 kOhm and climbing. Fuse (F7700) is good. DCIN on U7100 is 14.38V

- to Gnd, + to rail, didn't have to go over 2V to find the short.

Found the short and replaced C7582. No more short but now I'm running into the exact same issue as I describe in this post: https://www.rossmanngroup.com/boards/forum/board-repair-troubleshooting/29660-820-00164-no-power-weird-behavior-on-ppbus-g3h Waiting to see what's going on in the other...

2.3 Ohm between 17/18, 19.8 Ohm between 27/28. No power from battery but according to the magsafe when connected it is still charging, percentage unknown.

This board had a short on it which was resolved by replacing C7371. Now I still have no power but on PPBUS_G3H I have 500mV and slowly rising up to 1+V. Never seen behavior like that so not sure what to do or go after next. Checked all points for PPBUS_G3H they all show the same number. When I...

Much appreciate the education guys :)

Thanks to a tip from jadao on another post, Found the short. Had to set the Amps to max (5.1) and then start raising the Volts.

Thanks for the explanation jadao. So Amps = always at max, then I start raising the Voltage (just repeating to be sure). Will try that.

Injected power, up to 8.6V at 2.5A, nothing gets warm. Power supply outputs no more than 00.30V at those settings. This is the second board I inject and the second one that does not get warm, am I doing something wrong here? - to GND and + to the shorted rail, as you said. In this case + goes to...

Without heatsink, CPU does not get warm. Checked caps near jtag, don't get warm. No caps near the fuse itself except the ones feeding power into the fuse and those checked out.

Louis with the good news special! ;) as this is my first time injecting a board, is there a rule as to how high I can go on V/A? Figured 8.6V was at that point anyway so it’s safe but Amps wise I don’t know. Set to 8V 2A it only outputs 0.022V, is that enough to warm anything? Will check cpu...

Got a light on the charger but no power. PPBUS_G3H not present. I have 8.6V incoming on F7140 but 0V coming out. Replaced F7140 and put the board back in the Mac, connected battery and smelt something burning. Upon checking F7140 I had 8.6V going in, 0V coming out. Not sure if it was F7140 that...

Will test with - instead of GND tomorrow. jadao mentioned the same, was just waiting for confirmation that was the way to go :) EDIT: Yup, using - instead of GND everything works as it should. Thanks jadao and smiba for pointing that one out.

Nono, I used the 1V for test with meter. With the magsafe I use the Volts and Amps appropriate for that model Mac.

I set it to 1V and 1A, output is 20mV and dropping.

Smiba, this is the power supply Louis links to under his videos. I try to get tools and parts through his links/store so some cash flows his way as well through the affiliate program. It’s about $150. And if it’s good enough for a pro it should be good rnough for me I figured. Duke, because...

Tested with a few magsafe cables. Shield to ground, center conductor to +, set V and A... nothing. Different Mac, nothing. Guess I was sent a faulty PSU.

The cable works, took it from a charger that i used on that same Mac just minutes before. There's a white shielded cable in the center with a metal mesh woven around. I assumed that mesh was ground and the core was Voltage. There's no black. This is a 85W Magsafe 1 with L-connector.

Thank you Duke, will tinker with it this weekend :)

Hi Folks, I got the PPS2116A power supply and am having trouble getting magsafe plugs to work with it. The magsafe cable only has two wires in it, one is + and one is GND, when I connect it to the PSU and set the Voltage and Amps as printed on the original power brick the cable was attached...