Context: In the 1990s, Dell switched from using primarily ATX motherboards and PSU to using boards and power supplies with mechanically identical but differently wired connectors. This meant customers wishing to upgrade their hardware would have to replace parts with scarce Dell-compatible parts instead of commonly available parts. While motherboard power connections reverted to the industry standard in 2003, Dell continues to remain secretive about their motherboard pin-outs for peripherals (such as MMC readers and power on/off switches and LEDs).

Question: What decade did Dell switch to PSUs and boards that had differently wired connectors?
Answer: 1990s

Question: With what kind of parts were consumers able to upgrade their Dell systems with?
Answer: Dell-compatible parts

Question: What year did Dell revert its power connectors to industry standard ones?
Answer: 2003

Question: What part of their motherboards does Dell not reveal the specifications of?
Answer: pin-outs

Question: What decade did Dell switch to SPUs and boards that had differently wired connectors?
Answer: Unanswerable

Question: With what kind of parts weren't consumers able to upgrade their Dell systems with?
Answer: Unanswerable

Question: With what kind of parts were consumers unable to upgrade their Dell systems with?
Answer: Unanswerable

Question: What year didn't Dell revert its power connectors to industry standard ones?
Answer: Unanswerable

Question: What part of their motherboards does Dell reveal the specifications of?
Answer: Unanswerable