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STOP using lab PSU at this moment. The PSU is connected to an 85W MagSafe. There are only 2 wires to the power supply from the MagSafe, no? This is a LR technique, but the bench supply was at 16.5V. Begrudgingly, I did as you said, on an 85W 20V PS. And I'll fess up... Fan Spin! Also, the...

@2informaticos, I'm very sorry, but that/those were what I read, when I read it. I am only reporting voltages I had read. I understand why this is frustrating for you. I apologize on behalf of myself & the LB! :-) And now, there is no voltage in or out of U8020. VIN, EN and VOUT are all 0V...

Going down the PP3V3_SUS busses on pg.68: PP3V3_SUS_PCH_VCCSUS_GPIO = 3.3V PP3V3_SUS_PCH_VCCSUS_ICC = <can't measure> PP3V3_SUS_PCH_VCC_SPI = 3.3V PP3V3_SUS_PWRCTL = 3.3V PP3V3_SUS_P1V05SUSLDO = 3.3V (U7840 "SUS LDO" putting out 1V on PP1V05 _SUS_LDO = OK) PP3V3_SUS_PCH_GPIO = 3.3V...

Thanks for the reply & guidance, @2informaticos. A. PP3V3_S5 on p. 58/82, U7501 page: PP3V3_S5_REG = 3.3V measured at pin 1 (output side) of L7560: B. PP3V3_SUS was a little harder to track down, with some OK, and some no voltage: -PP3V3_SUS_ROM = 3.3V (pg.47, C6101, pin 1, which is VCC to...

Wrap-up. I sent this board to a shop in NYC, and there are too many layer shorts on the board to fix it. The power surge made even all the above not enough. I bought another LB, and have started a new thread about that board... Many thanks for those who helped all those hours I spent on that POS...

Experts, I have a purchased 820-4924-A, and it seems all my S5 voltages are there. But I'm working on the LB au naturel. I don't expect fan spin because the CPU is not turning on (heating up). The whole board is cool... It isn't going to S4, so my question is: Is this the point where I need to...

I was checking for pin shorts before powering up, and well, I must have had too much solder on U7100 pins 22, 23, 24, because they were all shorted together. I sucked out enough without lifting to unshort pin 24 (CHGR_UGATE), but pins 22 (GND) and pin 23 (CHGR_PHASE) remain shorted together...

@2informaticos I just lifted it, and pin 3 is 0Ω to the pad (pin 29), but without a schematic, I don't know why it isn't also grounded to pin 22 ("GND")... Right before I lifted it, I measured the full 16v across R7110, which I should have done yesterday. That told the story. Really appreciate...

Well, all MOSFETs replaced, and now I have a very strange symptom-once again on the U7100. First a pic for reference: This is from page 54 of the schematic for 820-4924-A. At pin 1 of R7110 I have good voltage ~13v. At pin 2 of R7110 I have nothing(!). So U7100 has nothing on pin 3 (ACIN)...

The charging circuitry is inside the laptop-that is, the current and voltage regulators. You can charge either on or off. For on, you just need to know the 'normal' current draw (without a batter in). That is your target. [1] LiPo (and other) batteries charge by hitting the device with full...

I realize this is old, but in case anyone searches here for USB C and PD... You can buy either adjustable modules: https://www.amazon.com/JacobsParts-Voltage-Trigger-Module-Adjustable/dp/B08NWG54LP ...or fixed ones (this one is 20v)...

Thanks @2informaticos! I screwed up and removed U7501, and cleaned/tinned the pins-all with the power on. Ordering dual MOSFETs for both sides now. It sounds like I shorted out Q7560 (if this is how they fail). Dohh!

Thanks @2informaticos ! I think I made progress. But first: "PCH requires high level on PM_BATLOW_L to start power on sequence. " Just by the name of the signal, does this mean a battery that is not 0% is required to boot? I must not understand the signal. re: Progress: 0. 820-4924-A p...

Thanks @2informaticos. You guys are great. The first 3 signals were all 3.3V, and PM_BATLOW_L was 0V, but that makes sense as the LB is not in the case. Checked the MOSFET "BATLOW# ISOLATION", nothing on any pin. Gate signal comes from PP3V3_S4_TBT, and U3210 seems to be off, with both...

Experts, I hit a wall, and could use your insights on how to get moving. A1502 820-4924-A 70mA when in case, 20mA when not. No fan spin. Unit is in S3AC mode, per chart on schematic p.64 using SMC_ADAPTER_EN, SMC_PM_G2_EN[ABLE], and SMC_S4_WAKESRC_EN Symptoms: 1. Every rareth time, system...

I know it's old, but if anyone else searches for that part, it is (currently) at aliexpress a ton cheaper than on ebay...: https://www.aliexpress.com/item/1005003442131314.html