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  1. M

    820-2877 with 0V optut on Q7910 and Q7260

    I have a 820-2877 board with all S3 power rails missing. The S5 ones are fine. P PDDR_S3_REG is 0.3V, all the other S3 rails are 0V. On Q7260, pin 5 is 12.60V, all other pins are 0. On Q7910, pin 3 is 3.322V, pin 4 is 3.344, all the others are 0. On U7200, pin 21 is 0V.
  2. M

    How to choose which power rail to investigate?

    Let's say I have a board with some problem on a certain state Six ( G3h, S5, S3, or S0). Some of the power lines are ok, some have a voltage close to the value expected, but still out or range ( for example 30%-40% below the expected value) , some have a voltage in the mV range, some are 0V...
  3. M

    820-2530, strange voltages on U7200

    Yes, I have the green led on the charger jack. I think SMC_PM_G2_EN is fine. I measured voltage between pin 1 of R7273 and ground and I get 3.401V. But on pin 2 of R7273 the voltage to ground is 14 mV. I also checked resistance 7273 and I get 43.1kohm, as opposed to 95kohm from a board where...
  4. M

    Are Are 820-2877-B and 820-2361-A compatible? and 820-2361-A compatible?

    So, 820-2877-B and 820-2361-A are electronically compatible, correct?
  5. M

    820-2530, strange voltages on U7200

    Yes, sorry, my bad. I meant, In diode mode, VReg3 = 0L VReg5 = 0L. Also, in diode mode L7220 is 0.601 and L7260 is 0.449, both measured to ground. Also, I have to mension that cap C7280 is missing, but the pads/ traces around it position look ok.
  6. M

    Are Are 820-2877-B and 820-2361-A compatible? and 820-2361-A compatible?

    I have some 820-2877-B boards to repair and a 820-2361-A DC in jack. Are the compatible? The connectors are physically compatible, but on eBay if zI search for A1342 (820-2877-B) dcin jacks, I get 820-2627-A. Is that the only one I can use on these boards?
  7. M

    820-2530, strange voltages on U7200

    Thank you for ypur reply. Please find below the info requested. V en0 (pin 13) is14mV; In diode mode, VReg3 = 0 VReg5 = 0 L7220 (pin 1 and 2) = 0.60V. What do you mean by L7220/60, exactly?
  8. M

    820-2530, strange voltages on U7200

    I have a board with all of the G3H powerails present, but on of the S5 rails present. I have the following measures from U7200: Vin (pin 16) =12.61V; Vref(pin 3)= 0V; Vfb2(pin 5) = 285mV; Vreg3 ( pin 8)= 260 mV; Vreg5 (pin 17)= 17mV; Veno(pin 13)= 14mV. Is this indication of a bad U7200? How...
  9. M

    Compatibility of peripherals between boards of the "same family"

    I have a mackbook A1278 820-2327-A and I 820-2530-A loose board which needs repairing. My question is: Can I use the magsafe dc-jack from the 820-2327-A macbook with the 820-2530-A board? Are they compatible? How about the peripherals? Both boards are for A1278 macbooks. Does it mean the...
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