A1989 (820-00850) - 5V@0.23A - shorted usbc cable

[wnt2fx]

dear fellow tech enthusiasts, I would appreciate your help ! I have an 820-00850 here that died on a squeezed/shorted charging cable.

I found several shorted ldo's on both U3100 and U3200. I replaced them with cd3215c00 ( originally c00Z )

D3301 was shorted, removed without replacement for now. No other visual / obvious findings. ports look good.

4,86V / 0,23A on usbc meter and ppbus 12.28V, ppdcin_g3h 5V and pp3v3_g3h 3.3V - all ports/orientation. Nothing obvious on a thermal picture, only t2 warms up to 35Celsius.

1V1 LDO missing on u31/32 ! all other LDOs present on all ACEs.

PP3V3_UPC_XB LDO and _TA LDO are present at U2890 / UB090


(Only when charger connected to the corresponding port/orientation (just one at a time)):

pp1v1_upc_xa_ldo_bmc - 0V

pp1v1_upc_xb_ldo_bmc - 0V

pp1v1_upc_ta_ldo_bmc - 1.1V

pp1v1_upc_tb_ldo_bmc - 1.1V

usb CC around 1.75V ( of which each time 6(7) do oscilate)

-

few diode mode readings:

pp1v1 ldo'S - all four around 0.47

pp20v_usbc_xa_vbus - 0.17

pp20v_usbc_xb_vbus - 0.13

pp20v_usbc_ta_vbus - 0.17

pp20v_usbc_tb_vbus - 0.13


this seems not ok to me. Am wondering if I should remove other diodes on pp20V lines, doubt the new or even the 2 left original cd3215 or if I should think about the tbt rom next. I am unsure what steps to take best next.

[mon2]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

U31/U32 are suspects. You must have the 1v1 ldo rail for the bmc communication to function to allow for the negotiations of the power delivery contracts.

The current draw is too high for the logic board in this state. The 5v default power rail is being pulled down from an excessive load.

Are these cd3215 devices from a donor board or purchased from a vendor? Properly reflowed and did the hot air 'dance' ?

The market does show parts available with c00 and c00z suffix. If you continue to have issues, source the c00z.

With no power, check the resistance to ground of each pp20v rail and the CCx (communication) line to compare. This may show us where there are damaged esd diodes.

[piernov]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

The current draw is too high for the logic board in this state.

Normal on T2 boards.

[mon2]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

More ...

https://boards.rossmanngroup.com/thr...battery.59438/

[wnt2fx]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

hey guys, thanks for helping out !

my soldering should be fine. due to often too low air flow for a real dance I confirm with light taps on the side if all is melted well, if the chip snaps right back.

Regarding wether to trust the source of the two cd32c00 I used or not is difficult to say. On the one hand the shop does not seem to have any products online since a while, on the other the general given feedback is ok. the precise feedback for that product is not available. https://www.aliexpress.com/store/3177036 Bought in october 21. One piece 6,25€. Same order cd3217b12 18€. Generally I look for good product feedback before buying.

So I can not be sure and should source few trusty cd3215c00z / donor boards clearly anyways. Will do so tomorrow. But as I can not yet be sure either that the ACEs are the problem I would like to look better into other possible reasons ( like diodes, cc lines, rom(s), maybe "scanning" for shot resistors / lines)

Thanks for your link mon2. I read that as well as https://www.badcaps.net/forum/showth...=104877&page=2 before. Confusing and of hints to follow, as well as https://logi.wiki/index.php/CD3215_Bootup_Sequence. Went over it again. Have to sort my thoughts. Will post CC lines resistance values later when I am back at the board. I find theese readings shady enough for the time beeing


2nd and 3rd values taken with highest manual kohm setting.


diode mode red GND / resistance red GND / resistance black GND

pp20v_usbc_xa_vbus - 0.17 / 12k / 50k ( 3rd value in auto mode: continuously jumping, high values to 0L )

pp20v_usbc_xb_vbus - 0.13 / 5k / 30k (dont remember auto mode readings but they had been constant)

pp20v_usbc_ta_vbus - 0.17 / 12k / 400k ( 3rd value in auto mode: continuously jumping, high values to 0L )

pp20v_usbc_tb_vbus - 0.13 / 5k / 30k (dont remember auto mode readings but they had been constant)

[wnt2fx]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

mixed something up so here pp20v_usbc_??_vbus resistances correction:

Only took traditional resistance now. Will maybe check later if I maybe made a mistake as well noting down Rs red GND.

-manual- because auto mode was oscilating/fluctuating

xa 50k
xb 30k constant "slow" falling -manual-
ta 380k -rarely it seems above 400 and then needs manual mode too for stated reason
tb 25k constant "slow" falling -manual-


CC Pins:

xacc1 xacc2 xbcc1 xbcc2 tacc1 tacc2 tbcc1 0L but USBC_TB_CC2 - 0.86M


Rs in circuit:

RB640 - 0.538k

RB630 - 0.481k

RB660 - 0.498k

RB650 - 0.577k

R3460 - 0.509k

R4350 - 0.529k

R3440 - 0.543k

R3430 - 0.499k

[Simplebeans]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

dear fellow tech enthusiasts, I would appreciate your help ! I have an 820-00850 here that died on a squeezed/shorted charging cable.

I found several shorted ldo's on both U3100 and U3200. I replaced them with cd3215c00 ( originally c00Z )

D3301 was shorted, removed without replacement for now. No other visual / obvious findings. ports look good.

4,86V / 0,23A on usbc meter and ppbus 12.28V, ppdcin_g3h 5V and pp3v3_g3h 3.3V - all ports/orientation. Nothing obvious on a thermal picture, only t2 warms up to 35Celsius.

1V1 LDO missing on u31/32 ! all other LDOs present on all ACEs.

PP3V3_UPC_XB LDO and _TA LDO are present at U2890 / UB090


(Only when charger connected to the corresponding port/orientation (just one at a time)):

pp1v1_upc_xa_ldo_bmc - 0V

pp1v1_upc_xb_ldo_bmc - 0V

pp1v1_upc_ta_ldo_bmc - 1.1V

pp1v1_upc_tb_ldo_bmc - 1.1V

usb CC around 1.75V ( of which each time 6(7) do oscilate)

-

few diode mode readings:

pp1v1 ldo'S - all four around 0.47

pp20v_usbc_xa_vbus - 0.17

pp20v_usbc_xb_vbus - 0.13

pp20v_usbc_ta_vbus - 0.17

pp20v_usbc_tb_vbus - 0.13


this seems not ok to me. Am wondering if I should remove other diodes on pp20V lines, doubt the new or even the 2 left original cd3215 or if I should think about the tbt rom next. I am unsure what steps to take best next.

Hi wnt2fx can you post all the voltage readings for the 4 LDO rails on all four of the CD3215's, So that's the U3100, U3200, UB300 and UB400. If you need any help with what signals you need to measure for this let me know.

And are you using a Genuine Apple 61W USB-C Power Adapter with the USB-C Charge Cable?

[wnt2fx]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

Hello dear helping people ! Sorry for never replying, I was damn out of order the last months. The problem is yet unsolved, did not spend a single second since back then. Will definetely get my head into this again bur rather in February because I have more urging things right now. Some of them electronics too so I will post for seeking help regarding other subjects before I continue in this one. I will check again with original 90+ apple charger, which I did not have back then. 4x4 LDOs to measure to be done. You mean each time plugged in another port ?
best regards

[Simplebeans]

Re: A1989 (820-00850) - 5V@0.23A - shorted usbc cable

Hello dear helping people ! Sorry for never replying, I was damn out of order the last months. The problem is yet unsolved, did not spend a single second since back then. Will definetely get my head into this again bur rather in February because I have more urging things right now. Some of them electronics too so I will post for seeking help regarding other subjects before I continue in this one. I will check again with original 90+ apple charger, which I did not have back then. 4x4 LDOs to measure to be done. You mean each time plugged in another port ?
best regards

Yes and whenever you are ready let me know and ill be glad to help.