Recent content by JdYoda

Found the problem near UB300. After i removed metal shield around U9290 i saw that pins of RB305 and RB303 doesn't looks good. After resoldering all of the resistors in this row mac turns on. Thank you very much

Hello! Can not get 20 volts on this board. Customer says that for last 2 days charging was unstable, then laptop just turned off Now there is 3 CD3215 in the loop, UB400 stable Board is clean, no corrosion, no oxidation Found blown resistor RB036 ( replaced) Already changed UB400 ( 2 times...

With disconnected LCD external video also missing. Laptop is on, i can hear a sound when i plug in a charger.

Sorry, i do have note book, but never faced missing cpu vcore before. External video is missing, customer says that laptop just didn't turn on in the morning

Hello! Mac A2141 turns on with battery, there is a chime, but PPVCCGT_S0_CPU is missing. No image, no backlight. USB activity is present, caps lock reacts Without battery doesn't turns on, 20v, 0.04a DFU restoring sucsessful. In SMC bypass mode doesn't start Before was short on PP2V5_NAND_SSD0...

Thanks for explanation

I found the problem, but it's a little weird... I decided to check all the pins under UB400 in diode mode, and found out that pin 36 ( UPC_TA_UART_RX ) has very low resistance, just 26 Ohm. This pin goes to resistor RB305, and it should be 1 MOhm. I removed RB305, puted back UB400 and mac works...

CD3215 is good 100%. Checked it on another board. Also traces is ok, checked each trace under UB400

Hello. Mac A1706 doesnt turns on. 3 of 4 CD3215 rebooting, LDO 1.1 present. UB400 steady 5V, 0Amps, no LDO 1.1v After changing UB400 no changes. Found out that all PPBUS lines are missing (ppbus_g3h, ppbus_hs_cpu, ppbus_hs_oth5v ) PPDCIN_G3H - 5v PP3V3_G3H - 3.3 Diode mode for ppbus lines is...

Thanks again for helping and explaining.

You right, R7900 was blown, 350k. There was only 1,5V on second pin. Now laptop works. Thank you so much! Really appreciate your help! So there was no power for U7800, is it correct?

Hello. Mac A2141 doesn't turns on. 20v 0.05A with battery, 5v 0.05A without battery. Found short on PP3V3_G3H_SOCPMU (C7805), after i changed cap - short is gone. Now PPBUS - 12.3v, PP3V3_G3H_RTC_X - 3.3v PP3V3_G3H_T - 0.4v Other voltages are missing, so no DFU as well...

Ok, so i've tryed to read the data from original U2890 and looks like it worked. I flash the original firmware to the U2890 from A2141 mac, and 20 volts is gone. DFU mode sucsessfuly reviving macbook, but still not charging, and no 20 volts now with original firmware...Board still turns on with...

Oh, my mistake, it's a typo...U2890 of course. I didn't find any. I have a CH341A programmer, do you think it is possible to read the firmware from original chip using this type of programmer? Or i should buy some special tool for this? Im at the small island in the middle of Indian ocean, no...

Sorry, I didn't really get it. You mean i need to search the firmware for U2980 in internet?