A cracked touchscreen. A dim, barely visible display. An operator panel that takes five minutes to boot up. These are the HMI problems that force maintenance managers into a tough decision: repair the existing unit or buy new?
Having repaired thousands of HMIs at Flexa Systems, here's what we've learned about when each option makes sense.
Common HMI Failures and Their Repairability
Cracked or Broken Touchscreen
Repairability: Excellent
This is the most common HMI failure and the easiest to repair. The touchscreen digitizer (the glass layer that senses touch) can be replaced independently of the LCD display underneath. If the LCD isn't damaged, only the digitizer needs replacement, keeping cost low.
Typical repair cost: $200-$800 depending on panel size
Typical replacement cost: $1,500-$8,000+ for a new unit
Dim or Dark Display (Backlight Failure)
Repairability: Excellent
If you can barely see the screen, or need a flashlight to read it, the backlight has failed. Older HMIs use CCFL (fluorescent) backlights that commonly fail after 5-7 years. We can replace the backlight or upgrade to LEDs, which last significantly longer.
Typical repair cost: $150-$500
Typical replacement cost: $1,500-$8,000+
Unresponsive or Drifting Touch
Repairability: Very Good
When touches register in the wrong location or the screen stops responding to touch in certain areas, the touchscreen digitizer is wearing out. Resistive touchscreens (used in most industrial HMIs) have a finite touch life and eventually need replacement.
Typical repair cost: $200-$600
Typical replacement cost: $1,500-$8,000+
Won't Power On / No Boot
Repairability: Good
When an HMI won't power up at all, the issue is usually the internal power supply or power regulation circuits. These components can be repaired or replaced. If the processor board itself is damaged, repair is still often possible but more involved.
Typical repair cost: $300-$1,200
Typical replacement cost: $1,500-$8,000+
Communication Failures
Repairability: Good
Ethernet, serial, or fieldbus ports can fail due to electrical transients, ESD, or simply wear. Individual port hardware can usually be repaired without replacing the entire unit.
Typical repair cost: $250-$800
Typical replacement cost: $1,500-$8,000+
Slow Performance / Freezing
Repairability: Moderate
If the HMI runs slowly, freezes, or takes a long time to change screens, the issue could be failing flash storage, insufficient memory, or a degrading processor. Storage can often be replaced, but processor issues may not be economically repairable on older units.
Typical repair cost: $300-$1,000
Typical replacement cost: $1,500-$8,000+
The Hidden Cost of HMI Replacement
Buying a new HMI isn't just about the hardware cost. Consider these additional expenses:
Application Reprogramming
If you're replacing with the same model, you may be able to transfer your application. But if the exact model is discontinued (common with HMIs older than 7-10 years), you'll need to recreate the entire application on a new platform.
- Simple applications (20-30 screens): $2,000-$5,000
- Medium applications (50-100 screens): $5,000-$15,000
- Complex applications (100+ screens with recipes, data logging, etc.): $15,000-$50,000+
Panel Cutout Modifications
HMI dimensions change between generations. If the new model doesn't fit the existing panel cutout, you'll need a new adapter plate or panel modification. Budget $200-$800 for fabrication.
Communication Protocol Changes
Older HMIs might communicate via serial (RS-232/RS-485) while newer ones use Ethernet. If your PLC only has serial ports, you may need a protocol converter or PLC communication module upgrade.
Operator Retraining
A different HMI platform means different screen layouts, navigation, and operation. While the process remains the same, operators need time to become familiar with the new interface.
When to Repair
Repair makes sense when:
- The failure is physical — cracked screen, dim backlight, dead port. These are straightforward repairs with predictable outcomes.
- Your application is complex — The more screens and logic in your HMI program, the more you save by avoiding reprogramming.
- The model is discontinued — Repair keeps your existing system running without the cascade of changes that come with a platform change.
- You need it fast — A repair can be done in days. Sourcing a new HMI, reprogramming, and commissioning can take weeks or months.
- Budget is constrained — Repair is typically 10-30% the total cost of replacement when you factor in all expenses.
When to Replace
Replacement makes more sense when:
- The HMI has been repaired multiple times — Repeated failures suggest end of life.
- You need features the old unit can't provide — Modern HMIs offer wider screens, better resolution, faster processors, and web-based remote access.
- Cybersecurity is a concern — Older HMIs often can't be patched and may have known vulnerabilities.
- You're upgrading the entire control system — If the PLC is being replaced too, it makes sense to match the HMI.
- The application is simple — A basic HMI with 5-10 screens is quick and cheap to reprogram on a new platform.
What About Your Program?
One of the biggest concerns with HMI repair is the application program. Here's the good news: in most cases, the program survives the repair. Touchscreen replacement, backlight repair, and power supply fixes don't affect the processor or storage where your program lives.
For repairs that do involve the processor board, we always attempt to preserve the existing program. If that's not possible, we'll let you know before proceeding so you can provide a backup.
Pro tip: Always maintain a backup of your HMI program on a computer or USB drive. This protects you regardless of whether you repair or replace.
Get a Free HMI Evaluation
Not sure if your HMI is worth repairing? Send it to us for a free evaluation. We'll diagnose the exact issue, provide a firm repair quote, and give you our honest recommendation on repair vs. replacement.
- All major brands: Allen-Bradley PanelView, Siemens SIMATIC, Pro-face, Omron, Mitsubishi, Weintek, and more
- 2-year warranty on all repairs
- Program preservation whenever possible
- Rush service available