crwdns2934243:0crwdne2934243:0 oldturkey03, Vendredi, Jacob Mehnert, BenZ78, and jayeff crwdns2934247:0crwdne2934247:0
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with mid 2017 A1534, board 820-00687. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. | |
| === Update (02/15/2023) === | |
| + | |
| [image|2864214] | |
| [image|2864213] | |
| As for the differences, I'm using a brd file for 820-00244, so far the only difference I found was at the XW8401 slot, which shows a component in the file but not present on the board. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934251:0crwdne2934251:0:
| + | 769575 |
|---|
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with mid 2017 A1534, board 820-00687. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. | |
| === Update (02/15/2023) === | |
| - | |
| + | [image|2864214] |
| - | Here they are, taken as best as I could: |
| - | |
| - | https://ibb.co/9bMpKBP |
| - | |
| - | https://ibb.co/DfKzy9c |
| - | |
| - | [image|2864214][image|2864213] |
| - | |
| - | Not sure if there's a better way of posting photos here. If so, I'll do that. |
| + | [image|2864213] |
| As for the differences, I'm using a brd file for 820-00244, so far the only difference I found was at the XW8401 slot, which shows a component in the file but not present on the board. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 oldturkey03
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with mid 2017 A1534, board 820-00687. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. | |
| === Update (02/15/2023) === | |
| - | |
| - | @tojaert I'm sorry, I didn't pick up on the request for photos. |
| + | I'm sorry, I didn't pick up on the request for photos. |
| Here they are, taken as best as I could: | |
| https://ibb.co/9bMpKBP | |
| https://ibb.co/DfKzy9c | |
| + | |
| + | [image|2864214][image|2864213] |
| Not sure if there's a better way of posting photos here. If so, I'll do that. | |
| As for the differences, I'm using a brd file for 820-00244, so far the only difference I found was at the XW8401 slot, which shows a component in the file but not present on the board. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with mid 2017 A1534, board 820-00687. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. | |
| + | |
| + | === Update (02/15/2023) === |
| + | |
| + | @tojaert I'm sorry, I didn't pick up on the request for photos. |
| + | |
| + | Here they are, taken as best as I could: |
| + | |
| + | https://ibb.co/9bMpKBP |
| + | |
| + | https://ibb.co/DfKzy9c |
| + | |
| + | Not sure if there's a better way of posting photos here. If so, I'll do that. |
| + | |
| + | As for the differences, I'm using a brd file for 820-00244, so far the only difference I found was at the XW8401 slot, which shows a component in the file but not present on the board. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| - | I've been trying to diagnose a problem with |
|---|---|
| + | I've been trying to diagnose a problem with mid 2017 A1534, board 820-00687. |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with 2016 or 2017 A1534. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. | |
| Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? | |
| + | |
| + | Edit: BKLT_EN_R coming from CPU to U8401 does go to 3.3v and stay there. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with 2016 or 2017 A1534. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the L8410 inductor. | |
| Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. | |
| I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. | |
| + | |
| + | Probably that "something" is U8401 which controls the Q8406 MOSFET which should be doing the pulsing. |
| + | |
| + | Are there any preconditions to U8401 initiating the pulsing? Or should I assume that it's dead? |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with 2016 or 2017 A1534. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| - | So far I think I've narrowed it down to something around the |
| + | So far I think I've narrowed it down to something around the L8410 inductor. |
| - | |
| + | Schematic says that after the inductor voltage should be around 45v, while instead it's 8.6 exactly like before it. |
| - | Before the backlight goes on, BKLT_EN_R is 0v and LCDBKLT_EN_L is 8.6v. |
| - | |
| - | After backlight goes on for a moment and then turns back off, BKLT_EN_R goes to 3.3v and stays there, LCDBKLT_EN_L drops to about 5.6v and also stays there. |
| - | |
| - | I assume from what I've read that LCDBKLT_EN_L should be dropping to zero, but it doesn't in this case. |
| - | |
| - | Any advice would be appreciated. |
| + | I assume something should pulse the input into it to boost the voltage for the backlight, but there is no pulsing. Just stable DC. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934245:0crwdne2934245:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
| I've been trying to diagnose a problem with 2016 or 2017 A1534. | |
| Doesn't turn on. | |
| When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). | |
| Negotiates and takes 20v properly from charger. | |
| Gives a chime when connecting the charger. | |
| I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. | |
| So far I think I've narrowed it down to something around the Q8406 MOSFET. | |
| + | Backlight fuse is fine. |
| + | |
| Before the backlight goes on, BKLT_EN_R is 0v and LCDBKLT_EN_L is 8.6v. | |
| After backlight goes on for a moment and then turns back off, BKLT_EN_R goes to 3.3v and stays there, LCDBKLT_EN_L drops to about 5.6v and also stays there. | |
| I assume from what I've read that LCDBKLT_EN_L should be dropping to zero, but it doesn't in this case. | |
| Any advice would be appreciated. |
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open
crwdns2934241:0crwdne2934241:0 The Man Himself
crwdns2947189:0crwdne2947189:0:
Only 1 second of backlight
crwdns2934249:0crwdne2934249:0:
I've been trying to diagnose a problem with 2016 or 2017 A1534. Doesn't turn on. When trying to turn on, LCD backlight comes on for about one second, and nothing happens after that, also there is no image while that happens or after (when shining a light on LCD). Negotiates and takes 20v properly from charger. Gives a chime when connecting the charger. I'm a complete novice in board level troubleshooting, so don't be surprised if I don't know something obvious. I did read up everything I could find. So far I think I've narrowed it down to something around the Q8406 MOSFET. Before the backlight goes on, BKLT_EN_R is 0v and LCDBKLT_EN_L is 8.6v. After backlight goes on for a moment and then turns back off, BKLT_EN_R goes to 3.3v and stays there, LCDBKLT_EN_L drops to about 5.6v and also stays there. I assume from what I've read that LCDBKLT_EN_L should be dropping to zero, but it doesn't in this case. Any advice would be appreciated.
crwdns2866306:0crwdne2866306:0:
Retina MacBook 2017
crwdns2915684:0crwdne2915684:0:
open