The dark beige/tan Commodore 1541 disk drive is rather well known. The lighter beige, almost white 1541c is more of a curiosity. The drives are closely related, but the difference is more than just the color.
The 1541 dates from 1982 to 1986. In 1986, the 1541C replaced it. It was a lighter beige color than the most common dark tan variant of the 1541—part of a broader initiative in mid-1986 to make Commodore’s product line look more up to date—but there were internal changes as well.
Regarding the color: Early home computers were dark beige or tan in color. In 1984, Commodore experimented with black computers, releasing the ill-fated Plus/4 and 16. 1985’s C-128 and Amiga 1000 used a light beige similar to the IBM PC and its early clones. In 1986, Commodore refreshed the venerable 64 and 1541 to match the 128’s design.
Commodore advertised that the 1541C had a track 0 sensor like the 1571, to eliminate most of the head knocking that made the 1541 the drive everyone loved to hate. Disk errors caused the 1541 to lose track of where the drive head was, so it would knock the drive head up against its head stop until it figured it out. Copy protection schemes (what we would now call DRM schemes) used disk errors, so loading games made for a loud drive. Someone in the next room could tell what game you were loading. It was irritating to your ears and your wallet. Over time, the knocking would cause the head to go out of alignment, which would prevent the drive from properly reading disks produced by a healthy drive. This was generally a $40 or $50 repair, so anything that eliminated that repair was welcome.
The problem was that the track 0 sensor didn’t always work. If you want to quiet a loud 1541C, cut jumper J3 on the main circuit board.
The 1541C took one other measure to improve reliability. Its ROM performed an initialization routine from time to time. Often when the original 1541 showed symptoms of being out of alignment, simply initializing a disk would fix it. This simple modification improved the reliability of the drive without adding any additional cost. However, if the track 0 sensor wasn’t working properly, it did make the drive a lot louder when it initialized without a disk in the drive.
Aside from those two internal changes and the cosmetic change, the 1541C was just like its predecessor.
By the fall of 1988, Commodore replaced the 1541C with the 1541-II. The 1541-II incorporated some of the changes that the better 1541 clones made. This included an external power supply and DIP switches that easily allowed multi-drive setups, and some cost reduction measures to make it cheaper to produce.