F1 fuse repair
The Dreamcast's controller board contains a fuse labelled F1 that can blow and cause the console's controller ports to no longer function. This fuse can be replaced by an automatically resetting fuse that will revert back to a functioning state within a few moments.
The stock part, despite being labelled as a fuse, most closely resembles a 1/4 W, 0.39 Ω ± 10% metal film resistor. Various electronics component retailers sell part number MFR-25FTF52-0R39 by Yageo, which matches these specifications (it is actually a little bit better, and as of January 2020 it costs less than $9 USD for 100 of them). Note the green band on F1 actually represents a temperature coefficient, specifically indicating a value of 20 ppm/K--that is, for every 1 K increase in temperature, the resistance may change by roughly 20 parts per million.
R1, the other resistor on the Dreamcast controller board, is a standard 1/2 W, 13 Ω ± 5% resistor matched by Yageo-branded part number MFR50SFTE52-13R.