5-Inch Custom Instrument Display — CRT to LCD Replacement Case Study

Compact 5-inch CRTs were once common in industrial instrumentation, measurement equipment, and dedicated machine controllers. As these CRTs fail, finding exact replacements is increasingly difficult — most have been out of production for over a decade. This case study covers a custom 5-inch TFT LCD replacement developed for a multi-function instrument display application.

The Challenge

The customer's instrument used a 5-inch monochrome CRT with an analog RGB input. The CRT had developed severe burn-in (permanent image retention from years of displaying the same readout), making critical measurements difficult to read. The original CRT assembly was no longer available, and the instrument's value didn't justify a full electronics redesign. A custom LCD replacement was the only practical option.

Custom 5-inch TFT LCD replacement module — front view | Source: Kongto Technology

Original 5-inch CRT — rear view with signal and power connectors | Source: Kongto Technology

New 5-inch TFT LCD — rear view with matched connectors for direct replacement | Source: Kongto Technology

New 5-inch TFT LCD — front view, drop-in replacement module | Source: Kongto Technology

The Solution

We provided a custom 5-inch TFT-LCD module (800×480 resolution, 400 cd/m², LED backlight) with an analog RGB input that reads the instrument's existing video signal directly. The mounting dimensions were matched to the original CRT bezel opening for a drop-in fit. The module accepts DC 12-24V input and includes an OSD for brightness/contrast adjustment. The entire upgrade is reversible and requires no permanent modifications to the instrument.

5-inch custom LCD in installation — matched bezel opening | Source: Kongto Technology

5-inch TFT LCD installed and displaying instrument readout | Source: Kongto Technology