Over years of use, the top mechanical components can degrade. Here are the top three issues users report, along with manual solutions:
This is the heart of the "top" that users ask about. The FMX-002 has three membrane buttons located conveniently under your thumb when held naturally:
The HOLD / ZERO Button (Center / Top-Center)
The MODE or ION Button (Right / Top-Right) simco fmx002 manual top
Cause: The internal chopper (vibrating shutter) is failing or the top PCB connection is loose.
Fix:
Q: Can I use the Simco FMX-002 with the manual top removed?
A: No. The manual top contains the chopper reference. Operating without it will give false readings and may damage the sensor.
Q: My manual top won’t close completely – is there a fix?
A: Yes. The top uses a tiny leaf spring. Open the cap and bend the spring back 2mm using fine needle-nose pliers. Over years of use, the top mechanical components can degrade
Q: Is the manual top different from the auto top?
A: No – it is the same physical part. “Manual top” refers to the operational mode, not a different hardware SKU.
To comply with ISO 9001 or ESD TR53, you must verify calibration every 6-12 months. The manual top gives you access to the offset and gain trimmers.
At the very top of the FMX-002 is a plastic housing containing a vibrating chopper-type sensor (also known as a field mill). This is not a simple metal plate. It requires care: The HOLD / ZERO Button (Center / Top-Center)
A: No. That means the field exceeds the selected range (usually ±20 kV). Move the meter farther from the charged object. The top display will show “OL” (overload) if too close.
Warning: Avoid third-party "manual aggregators" that require payment. Simco generally provides the FMX-002 manual for free.