Editing Commodore 64 (section)

=== Power supply ===
[[File:Commodore 64 - Joystickports, EinAus-Schalter, Poweranschluss.jpg|thumb|alt=Rear of a C64|{{nowrap|Joystick ports}}, {{nowrap|power switch}}, {{nowrap|power inlet}}]]
The C64 used an external [[power supply]], a linear transformer with multiple taps differing from [[Switched-mode power supply|switch mode]] (presently used on PC power supplies). It was encased in [[epoxy]] resin gel, which discouraged tampering but increased the heat level during use. The design saved space in the computer's case, and allowed international versions to be more easily manufactured. The [[Commodore 1541|1541-II]] and [[Commodore 1581|1581]] disk drives and third-party clones also have external power-supply "bricks", like most peripherals.

Commodore power supplies often [[Mean time between failures|failed sooner than expected]]. The computer reportedly had a 30-percent return rate in late 1983, compared to the 5–7 percent rate considered acceptable by the industry;<ref name="Infoworld Nov 1983">{{Cite magazine | last = Mace | first = Scott | title = Commodore 64: Many unhappy returns |magazine= InfoWorld | volume = 5 | issue = 46 | page =23 | publisher = Popular Computing Inc. | date = November 13, 1983 | url = https://books.google.com/books?id=wS8EAAAAMBAJ&pg=PA23 | issn = 0199-6649}}</ref> ''[[Creative Computing]]'' reported four working C64s, out of seven.<ref name="anderson198403">{{cite news | url=https://archive.org/stream/creativecomputing-1984-03/Creative_Computing_v10_n03_1984_Mar#page/n57/mode/2up | title=Commodore | work=Creative Computing | date=March 1984 | access-date=February 6, 2015 | last=Anderson | first=John J. | page=56 | author-link=John J. Anderson}}</ref> Malfunctioning power bricks were notorious for damaging the RAM chips. Due to their higher density and single supply (+5V), they had less tolerance for over-voltage. The usually-failing [[78xx|voltage regulator]] could be replaced by piggybacking a new regulator on the board and fitting a heat sink on top.<ref>{{cite web|url=https://www.youtube.com/watch?v=vWP_ELDb0Ls| archive-url=https://ghostarchive.org/varchive/youtube/20211211/vWP_ELDb0Ls| archive-date=2021-12-11 | url-status=live|title=Commodore C64 Dangerous Wedge PSU Repair|website=[[YouTube]]|access-date=May 13, 2021|date=November 1, 2020}}{{cbignore}}</ref>

The original [[Power supply unit (computer)|PSU]] on early-1982 and 1983 machines had a 5-pin connector which could accidentally be plugged into the computer's video output. Commodore later changed the design, omitting the resin gel to reduce costs. The following model, the Commodore 128, used a larger, improved power supply which included a fuse. The power supply for the [[Commodore REU]] was similar to that of the Commodore 128, providing an upgrade for customers purchasing the accessory.