Recent content by cchamberlain

Hi, I just wanted to provide a final update and to say that unfortunately I'm going to have to abandon the repair. I reballed the chip I bought from see-ic which is supposedly compatible with the 01041 board, and this time the reball was good. However, after installing it on the board I went...

Hi, Actually the recycled U7800 is from an 820-01814-A board. I bought it as a 820-01041-A board after you said that the U7800 should work from it, but it looks like the seller sent me the wrong one and I didn't notice until I had already removed the chip. It looks quite similar to the 01700...

Hi, I went through the power sequence as specified in the schematics and below is the result. It looks like I'm not getting PVDDQ_EN_R. This line is driven from U7700 (P2V5_VPP_PGOOD line) via R7756. I checked the PVDDQ_EN line which is the enable signal for U7700 and it is also 0V. Diode mode...

Forgot to mention - I went through the power sequence for the 820-01700 from repair wiki and got quite far through it including 2.5V on PP2V5_NAND_SSD0/1 and PP0V9_SSD0/1 I also found that PP3V3_S5 and PP1V8_S5 both sit at 0V but pulse at least twice to 3.34 and 1.80V respectively a short time...

I tried a reflow of U7800 with plenty of flux around it and blown under it, which went pretty well and I got a successful response to the little bump with the tweezers. But exact same result when powering up again. Maybe I need to remove U7800 and have one more attempt at replacement to try to...

Okay so the diode mode readings from the Power FETs are as follows: U8215 (PP3V3_G3S_X) = 0.340 U8210 (PP3V3_G3S_T) = 0.423 U8220 (PP1V8_G3S) = 0.302 U8240 (PP1V2_S0SW) = 0.281 U8297 (PP3V3_S0SW_TBT_X) = 0.529 U8295 (PP3V3_S0SW_TBT_T) = 0.527 Note that sense resistors R5720 and R5730 are both...

Sorry, on my schematic that was Page 79 of 200 (Sheet 76 of 135) so I guess you must mean Page 82 of 200 (Sheet 79 of 135). This is entitled "Power FETs"?

PP1V8_G3S is at 1.799V as measured at L6301 PP3V3_G3S_T is at 3.34V as measured on C5051 PP3V3_G3S_X is at 3.38V as measured on TPC4H5 L7700 is 0.398 DM and 0.000V L7701 is 0.091 DM and 0.000V L8102 is 0.099 DM and 0.000V Page 79 outputs V3P3/VOUT_RTC = 0.135 LDO_CORE = 0.359 LDO0 = 0.213 LDO1...

I tried a second revive which also completed successfully but again with nothing shown on the display. I then did a DFU restore which also completed through to the lock symbol on the host computer but again no change. I just did that restore a second time with the same result. I noticed that...

Update: I managed to use the keyboard to get it into DFU mode and completed the T2 revive process. This ended with the DFU symbol on the host Mac changing to a lock symbol but still nothing on the display of the guest machine and no fan spin. I'll check for voltages as per the power sequence chart.

Hi, yes I am using the 96w charger and associated genuine charging cable. While waiting to hear back from you I went ahead and installed the board temporarily in the top case and connected up the battery and BMU cable. Now when I plug it in, it goes to 20.5V and appears to start charging the...

Hi, Happy to report that I have replaced U7800 (PMU) again and this time it looks as if it is working. I also replaced the two fuses and R7900 and now my board is switching to 20V (20.54V actually) and PPBUS_G3H goes to 12.6V. It draws up to 0.36A at 20.54V before dropping back to 0.000A after...

Update: I think I've found the source of the short. I found a short across C7829 which is also connected to L7810 (Line PPVDDCPUSRAM_AWAKE) This line runs at 0.8V to 1.06V at 1A max so I set up 1V on my PSU and 1A current limit and injected voltage on this line using IPA alcohol to indicate...

Hi, I'm not sure if I'm doing what you are asking but here are the diode mode results with placement of red and black leads noted in the column headers. Nothing matches exactly and only the CPU and GPU supplies come close.

Since I took the readings earlier, the diode mode to ground (red on ground) for PPBUS_G3H has changed slightly to 0.402. Maybe due to capacitors discharging while it was powered down for a couple of hours. Anyway, I used this 0.402 figure to search for a coil with similar diode mode value to...