Repair guide

Check a CRT monitor that shows nothing, while staying safe

Many CRT faults are the cable, the source or a setting, so work through the outside checks first. Anything past the case needs stored-voltage knowledge, so stop and hire a professional.

Open the interactive checklist Tick off each step as you go. It saves in your browser.

Display · Careful · about 45 minutes. Worth doing. Reports say this fix helps on many machines.

You are in the right place if: The monitor has no picture, a rolling or pinched picture, or the wrong colours.

Before you start

A CRT can hold lethal high voltage after being unplugged. Do not open the case or touch the tube neck or anode cap.
Do not discharge a CRT yourself unless you are trained.
If there is smoke, a burning smell or a loud crackle, unplug and stop.

Board revisions and models

Commodore 1084 revisions and the Apple RGB monitors have different known faults.

Parts you may need

Replacement video cable. Rule out the cable Amazon · eBay
Signal source for testing. Isolate the fault Amazon · eBay

Tools

Second computer or console. Test the monitor Amazon · eBay
Multimeter. Check wall power only Amazon · eBay

Affiliate links. As an Amazon Associate I earn from qualifying purchases. These links only search by name. Disclosure

Step by step

Check the source Try the monitor on a second computer or a signal generator.
Check the cable and connector Try a known-good cable and look at the connector pins.
Check the controls Reset brightness, contrast and any mode switch.
Check power and fuses on the outside See if the monitor powers on, shows a light and warms up.
Listen and look Listen for a high-pitched sound and look for a faint glow on the tube.
Try the degauss function If the monitor has a degauss button or does so at power-on, try it once.
Look for the obvious Check for loose or burnt smells, but do not open the case.
Search for the model's known faults Look up the model's common faults before booking repair work.
Stop if it is internal Anything inside the case, including the tube and the high-voltage area, is for a trained technician.

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us.

Tip (Medium confidence). CRT Database lists common faults and manual links for the 1084S-D2. Source
Story (Medium confidence). A 1084S-D forum thread cured a pinched picture by replacing two capacitors, which is a job for someone qualified. Source

Guides we used

We wrote the steps in our own words from these. They have the photos and the full detail, so please read them and support their authors.

Commodore 1084S-D2 (CRT Database) (Wiki) by crtdatabase.com. Page with service manual links and common faults for the 1084S-D2.
CRT monitor display distortion problem (Forum) by EEVblog forum. A 1084S-D worked example where a pinched picture was fixed by replacing two capacitors; also notes brown glue residue.

Boards and models vary, so check what is in front of you. A repair can involve hot tools, chemicals and, on some machines, dangerous voltages. You do it at your own risk.