I think 820-00281 is the closest schematic/boardview for your board.
In this case, GMUX U9850 is fried...
In this case, GMUX U9850 is fried...
-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
820-00928 A1707 No Display
- Thread starter iambehr
- Start date
GMUX is supposed to have firmware...
iambehr
Member
Hmm.. source? I read the datasheet, and my admittedly poor understanding of the chip design makes me think that it is just a high speed capable switch, and it's outside behavior is controlled by the Dx_SEL pin on the chip.
Or do you mean that the system firmware has to have the proper GMUX chip specified in it?
Or do you mean that the system firmware has to have the proper GMUX chip specified in it?
Get GMUX from same donor board...
Apple is actually trying to make the repair as more dificil possible.
Even charger chips have firmware.
So be aware and replace any chips susceptible to have firmware only with chips removed from identical donor board...
Even charger chips have firmware.
So be aware and replace any chips susceptible to have firmware only with chips removed from identical donor board...
ALB-Repairs
Member
I have a 00281 with this issue. Tried a to replace u9850 from a 820-3787 with no change in symtoms. Ive now pulled the MUX chip of a scrap 00928 and will get back to you with results
ALB-Repairs
Member
I Put a u9850 from another 15 touchbar and still have no internal display. I will do some more digging and swap some more parts out until it works
Don't waste time, if you can't get GMUX from the same board model...
ALB-Repairs
Member
u9850 is not the commonly known programmed GMUX. I pulled from the same model anyway. That is not the only thing failing on these boards when those lines short.