820-01814_A Power cycling between 5v.040 A to .468A then it repeats

[J_george]

I would like some help and advice which will be much appreciated, I am looking at a mac Macbook Pro A1990 board 820-01814-A. When I connect the USBC meter via external Power Supply I see Power cycling between 5v.040 A to .468A then it repeats.
After doing some diode tests I get a complete Short on L9530 which is the output inductor for PP1V8_ssd1.
I have given the screenshot here, I would like your recommendation and advice if anything I need to test get this issue sorted Or is it SSD short , Your help on this will be much appreciated

[mon2]

What is the exact resistance to ground of L9530? No power during this resistance checking.

Would you have an adjustable dc power supply for voltage injection? Use it to dial up 1 volt (not higher); 3-5A current. Apply this voltage at L9530. Check who is heating up.

Hope it will be a capacitor. When found, flux and remove it. Then test the resistance again at L9530.

[J_george]

Thanks mon2 for your help , I have shown here the picture of Diode mode reading while probes shorted and while testing at L9530 .
I do have Adjustable bench top Power supply I will do the test today a as per your advice and come back with what I see,
Just a clarify my understanding, I need to feed that 1 V nearly 5A setting to the point where the PP1V8_SSD1 of the Inductor ?

Thanks again

[J_george]

I should have simply said Diode reading 0.001 .

[mon2]

Yes. There is a short on this power rail. Proceed with a 1 volt (not higher) voltage injection at the power inductor- downstream / consumer side. If practical, you can lift one side of this inductor to isolate which side of this inductor is shorted. Use lots of flux.

[J_george]

Thanks, mon2 again. Here I have attached pictures of what I see, please check and tell me if my setup is correct if so I see that U9200 is only the component that gets hot. That is worrying not sure of the IC.

Any advice on this would be greatly appreciated

[mon2]

https://boards.rossmanngroup.com/thr...-ground.61529/

[J_george]

Thanks for letting me know , I have informed the customer ,
Thanks I got to learn something here.

Thanks everyone .it is a great to have this forum.