Sony PVM-20M4U

March 1, 2024, 3:56 pm

Summary

Featuring one of the latest developments in Sony display technology, the HR Trinitron, the M4 Series of monitors has a resolution of 800TV lines.

With stunning picture performance, flexibility of signal connections, a full range of optional functions and ease of operation, these new Sony monitors are designed to meet the demands of a wide range of picture monitoring and production applications.

Good all-around PVM for sitting on your desk or other space-saving applications. Not the most reliable PVM series but common repairs are well documented.

There were several board revisions, getting a later model-year will ensure a more reliable experience. Sony changed the spec of several commonly failing capacitors.

Literature

Common Repairs

  • Power Supply Failure: Try testing with known good PSU if available. If not available test PSU outputs with load to see if voltage is within spec printed below connector. Regulators commonly fail. Cap failure less likely but still possible.

  • 3 RGB lines at top of screen: Check if underscanning (either with toggle swith or due to V-Height). If not underscanning then there is a deflection capacitor failure. Replace C-572 and C-584 on A Board. There is an old reccomendation to adjust the V-BLNK (V-Blanking) value in the serivce menu to 'push' the lines up off of the screen but this is not reccomended and only a temporary fix at best. It can further accelerate the death of the aforementioned capcitors and cause damage to other components. More information here: RetroTech on YouTube

Notes

OSD Service Menu can be accessed by pressing Menu, then Menu + Degauss. New settings won't be saved unless you commit them to memory by pressing Degauss. If you want to recall a setting from memory, press Blue Only.

Removing Tint Coating

This specific model has been verified as having a tinting/anti-glare coating on the screen glass from the factory. In severe cases where the screen has distracting scratches or damage that prevent regular use, you may consider removing this coating to expose the bare (hopefully undamaged) glass surface of the CRT. By removing the coating you will remove some of the tint on the glass that helps give it contrast in daylight and also helps slightly to prevent glare.

To remove the coating you have to remove the tube from the chassis entirely (in rare cases the CRT has a removable bezel but this is almost never the case - the 20L5 has a removable bezel for example) and start peeling it off from the corner. You can use an x-acto knife to get the peel started and then just slowly pull it back section by section.

Gallery

Sony PVM-20M4U