macbook A1708 820-00840-A

[mon2]

This rail should be active after the TBT rom has booted.

Check the other LDO rails on the CD3215:

PP3V3_UPC_XB_LDO
PP1V8_UPC_XB_LDOA
PP1V8_UPC_XB_LDOD

[PITERPENY]

PP3V3_UPC_XB_LDO=3.3V
PP1V8_UPC_XB_LDOA=1.8V
PP1V8_UPC_XB_LDOD=1.8V
I don't understand why it doesn't switch to 20V

[mon2]

The cd3215s must be all operational to switch. Check the voltage on each pin of the TBT rom. The TBT rom firmware may be corrupted. There are dumps of the firmware available on this website.

[PITERPENY]

Thunderbolt is U2890?

[PITERPENY]

Can I get it from another board?

[PITERPENY]

it worked! Mac works! thank you for your help, this is the first time I've encountered such a problem as a non-working thunderbolt!

[mon2]

Ghetto is about right. Glad to hear of some success for today. Time for another episode of Top Boy (Netflix). Soon I will be able to speak Brit / Jamaican slang...

[PITERPENY]

Ghetto is about right. Glad to hear of some success for today. Time for another episode of Top Boy (Netflix). Soon I will be able to speak Brit / Jamaican slang...

This is wonderful ! good luck with this))