Fix for "blown ADB Controller," replace the fuse on the PCB?

[Trash80toHP_Mini]

Found something interesting: a simple repair for a board with a "blown ADB controller" in the Wikipedia Article on ADB:

One peculiarity of ADB was that in spite of being electrically unsafe for hot-swapping on all but a few machines, it had all of the basic capabilities needed for hot-swapping implemented in its software and support hardware. On practically all original ADB systems it is not safe to plug in or unplug a device once the system is powered on (unlike modern day busses designed with hot-swap in mind). This could cause the opening of a soldered-in fuse on the motherboard. If brought to an authorised dealer this could result in a motherboard swap at a significant expense. A simple alternative was to obtain a fuse at a nominal cost and wire it in parallel across the open motherboard fuse (not even requiring soldering if done appropriately)

Insert usual warning here about info posted on Wikipedia.

 

[Unknown_K]

I don't think all boards with ADB had fuses.

Going by the Guide to the Macintosh Family Hardware Second Edition:

SE, SE30 no fuse (page 293)

II, IIx, IIcx, IIci 1A fuse on the 5V line (Page 294)

IIfx 1A fuse on the 5V line (page 295)

Mac Portable no fuse (page 299)

 

[Trash80toHP_Mini]

I don't think all boards with ADB had fuses.

Likely a safe assumption, almost undoubtedly removed to "save room" on Compact PCBs and to lower costs on all later models. :

I might just cut the lines and add fuses to my KVM'd Compact Macs or any others I find lacking protection. Maybe just add it to the ADB in and out connectors of the KVM?

 

[Unknown_K]

If they are fast acting enough.