RAY CARLSENS  C= REPAIR ARTICLES

                    Information to help you diagnose, repair and improve your Commodore computers and periferals.
                   This page is a mirror of the articles on http://personalpages.tds.net/~rcarlsen  Schematics for CBM
                   equipment can be found at http://staff.washington.edu/rrcc                       latest updates: 11-20-07


Diagnosis and repair of the VIC20 (early and late versions)

Repairing the C64: chips vs symptoms.
C64 "blank screen" symptom: what it means and how to fix it.
The C64C... diagnostics and repair.
Adding a fan to your C64, SX64 or 1541.
Adding a reset switch to your Commodore computer.
PLA replacement in a C64 using an EPROM and adaptor

SX64: disassembly, diagnosis and repair.
SX64: how to add a computer reset switch without drilling any holes in the case.
SX64 disk drive replacement: how to swap the mechanism with one from a stand-alone 1541.

The Commodore Plus/4 computer: a beginners tutorial.
That crazy square connector... how to change the power socket on the Plus/4 so you can use a C64 supply.

Repairing the C128: chips vs symptoms.
C64/128 memory problems: "out of memory in 0" error message, and others.
C64 & C128 "joystick" control ports: diagnosis and repair of the ports, joystick, mouse, paddles, etc.
How to add a fan to your Commodore C128DCR (Metal Case USA model)
How to upgrade the C128 from 16K to 64K of VRAM.
C128 80 column picture "bending" and distortion on Commodore monitors.

Repairing your 1541 disk drive: chips vs symptoms, diagnostics.
Repairing your 1541 disk drive: diagnostic procedures.
The 1541-II: diagnostics and chips vs. symptoms.
Adding a reset switch to your Commodore disk drive.
A simple modification to safely defeat write protection without disabling disk change updates.
Repairing the 1571 disk drive: common problems and solutions.
Bug fixes and diagnostic procedures for the 1581 disk drive.
How to add a device change switch (8 to 9, 10, or 11) to your Commodore disk drive.
The MSD-SD2: how to install a device # select switch and other info.
MSD-SD2, link to operators manual, schematics and service info.
The disk drive "transit" card, what it's for and how to make your own.  .jpg image

Color monitor setup adjustments: how to do convergence, purity and greyscale.
How to replace the power switch in your Commodore monitor.
How to desolder and replace chips in your Commodore equipment.
How to repair a broken audio/data tape cassette.
How to clean and repair your Commodore keyboards.
Connector pinouts for Commodore equipment.
How to make and install heat sinks for IC chips in Commodore equipment.
Repairing a "wall wart" power supply.
How to safely test and evaluate the C64 "black brick" power supply.
Schematic for a repairable C64 power supply (.jpg).
The computer saver: an add-on to protect your computer from the "black brick" supply.