Wafer Prober — Used Alessi MH-4 (Alessi)

How Much Does Used Alessi MH-4 Cost in 2026?

The used Alessi MH-4 wafer prober typically sells in the range of $950, depending on its condition and the vendor. Units in "B" grade condition, which is common for this model, tend to fall within this price bracket. For units in "A" grade condition—meaning they’ve been fully refurbished and tested—prices can rise to $1,200–$1,400, depending on the vendor and the extent of the rebuild. Refurbishers like Ferrotec and Axus Technology are known to offer these units at a 40–60% discount compared to new Alessi models, which can cost upwards of $2,500.

Buying a used Alessi MH-4 can save a fab up to $1,500 per unit, which translates to significant cost avoidance in a multi-unit purchase. However, if a unit fails within the first 6 months due to poor maintenance or hidden defects, the cost of downtime and repair can exceed $3,000, especially if it disrupts a critical testing process. It’s important to note that units over 10 years old may require more frequent maintenance, which can erode savings over time.

Used Alessi MH-4 Specifications and Compatible Tools

The Alessi MH-4 is a compact, manual wafer prober designed for low-volume testing environments. It typically supports wafers up to 6 inches in diameter and features a standard 4-point contact system. The unit commonly has a resolution of 50 microns and a repeatability of ±10 microns. Lifespan metrics are typically measured in testing cycles, with units averaging 10,000–15,000 cycles before requiring major service.

This model is commonly compatible with older Alessi test systems from the early 2000s, such as the Alessi TPS-3000 and TPS-4000 series. However, it is not compatible with newer systems like the Alessi TPS-7000, which requires a different interface protocol. Attempting to use the MH-4 with incompatible systems can lead to signal errors and potential damage to the prober head, costing up to $2,000 in repairs.

What to Check Before Buying a Used Alessi MH-4 in 2026

1. Production Year: Units produced before 2012 may use outdated PCBs that are difficult to source. Reject any unit older than 2010 unless it has been fully upgraded.

2. Prober Head Condition: Inspect the contact tips and springs for wear. If the contact resistance is above 10 ohms, the unit may not meet testing standards. Use a multimeter to test continuity and a visual inspection for corrosion.

3. Motor and Stage Movement: Run the X/Y stage through a full range of motion. If the stage drifts more than 20 microns over 10 minutes, the motor or encoder may be failing. A failed motor can cause a full system lockup, requiring a $1,200 repair.

4. Power Supply and Safety Switches: Test the emergency stop function and verify that the power supply outputs are within 5% of rated voltage. A faulty power supply can cause unexpected shutdowns, costing $500–$800 in lost production time.

5. Documentation and Service History: Ensure the unit comes with a full service log and calibration certificate. Units without proper documentation may have hidden issues that surface during operation.

FAQ

Q: Can I use the Alessi MH-4 with a 2015 Alessi TPS-5000 system?
A: No. The Alessi MH-4 is not compatible with the Alessi TPS-5000 due to a different interface protocol. Attempting to connect them can result in a $1,500 repair bill from damaged components.

Q: Should I buy an Alessi MH-4 if it has 12,000 test cycles?
A: Yes, but only if the unit has been recently serviced. Units with over 12,000 cycles typically require a full rebuild every 3–5 years. If not maintained, they can fail within 6 months, causing $2,000 in downtime costs.

Q: How long can a used Alessi MH-4 last with regular maintenance?
A: With proper maintenance every 18–24 months, a used Alessi MH-4 can last 8–10 years. Units that are not maintained regularly may fail after 5 years, especially if they exceed 15,000 test cycles.

Q: What’s the difference in cost between a "B" grade and "A" grade unit?
A: A "B" grade unit typically costs $950, while an "A" grade unit from a refurbisher like Ferrotec can cost $1,300. The "A" grade unit includes a full rebuild and recalibration, which can prevent $1,000–$1,500 in potential repair costs over the first year.

Q: Is it worth buying a used Alessi MH-4 instead of a new one?
A: Yes, if you need a secondary or backup unit. Used Alessi MH-4s offer 40–60% savings over new models and are suitable for low-volume or non-critical testing. However, avoid buying units over 12 years old unless they’ve been fully upgraded.