Defective Secondhand Nihon Kohden JE-921A EEG Junction Box

Objective AI Report

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Report date: 07.12.2025

NIHON KOHDEN Neurofax JE-921A EEG Input Box Analysis Report

Device Detection and Identification

The product examined is an EEG (Electroencephalography) input box used in the field of medical diagnostics, which collects signals from electrodes connected to the patient and transmits them to the main device. It can also be defined as a junction box or patient input unit. In addition to standard electrode inputs for measuring brain activity, the device features respiration, SpO2/CO2, and DC input ports. This hardware is the patient-side module for Nihon Kohden’s EEG systems (Neurofax series).

Brand and Model Information

The logo, serial label, and product design features in the visuals have been thoroughly examined, and the following information has been determined with 100% certainty:

• Brand: NIHON KOHDEN
• Model: JE-921A (Verified on the device’s bottom label and in its design features)
• Product Series: Neurofax

Areas of Use

This product is designed for use in Neurology and Sleep Laboratories. Its primary purpose is to record the brain’s electrical activity (EEG) via electrodes placed on the scalp. Additionally, thanks to its extra input ports, it can be used for monitoring respiration, oxygen saturation, and other physiological parameters during Polysomnography (sleep study) recordings. This unit does not operate independently; it must be connected to a compatible Nihon Kohden Neurofax EEG main unit to process and display data.

Visual Condition and Physical Deformation Analysis

Very prominent and severe damages affecting the structural integrity of the product have been detected on the device’s outer casing:

• Case Crack and Breakage: Upon examining the rear and side profiles of the visuals (especially images 3 and 4), a very deep and long crack is present in the device’s left rear corner, between the mounting plate and the outer plastic casing. Separation has occurred in the plastic component, and the crack extends from the device’s joint to the screw hole.
• Color Change: Typical yellowing (especially on the side and rear surfaces) has been observed on the device’s plastic casing, attributed to use and time.
• Cleanliness: While the front panel and the area containing the electrode inputs appear relatively clean, dust accumulation is present in the casing details.

Connection Ports and Technical Specifications

Upon detailed examination of the front panel, the following technical inputs and controls have been identified on the device:

• EEG Electrode Inputs: Numerous electrode input sockets (FP1, FP2, C3, C4, O1, O2, etc.) arranged according to the International 10-20 system, placed on a head region map.
• Extra Inputs (Bipolar): Dual-pole inputs labeled X1, X2, X3, X4.
• Respiration Sensor Inputs: Inputs labeled X5 (RESP F), X6 (RESP C), X7 (RESP A).
• Sensor Module Inputs: Special connector sockets labeled SpO2/CO2 and DC1/DC2 at the bottom.
• Side Panel Inputs: DC 3, DC 4, DC 5, DC 6, and MARKER inputs are located on the side of the device.
• Control Panel: Impedance check (IMPEDANCE CHECK) button and impedance selector (SELECTOR kΩ) button, along with status LEDs (2, 5, 10, 20, 50).

Mechanical and Electronic Component Status

Mechanical Condition: While the metal mounting plate (bracket) on the back of the device appears sturdy, the broken plastic casing around this plate compromises mechanical mounting safety. The hanging and clip mechanisms are in place.

Electronic Components: Although the internal electronic circuit of the device cannot be accessed from the visuals, the inside of the connection ports (sockets) on the front panel appears physically clean. No visible corrosion or bending has been detected on the pins.

Quantity Information

Only 1 unit of the NIHON KOHDEN JE-921A EEG input box is present in the visuals.

Label and Certification Information

The following symbols and information are present on the device’s rear label:

• Brand Information: NIHON KOHDEN CORPORATION.
• Certification: CE mark is present (conformity to European standards).
• Warning Sign: WEEE symbol (crossed-out wheeled bin) indicates that the device should not be disposed of with household waste.
• Model Label: Although partially readable as JE-9…, it has been confirmed as JE-921A through design analysis.

Potential Failure Risk

A “Good condition” comment cannot be made for this product. The potential risks identified are as follows:

• Structural Integrity Risk: The deep crack and breakage in the rear casing indicate a risk of the device falling or completely disintegrating when attached to its mounting bracket. This crack likely resulted from a severe impact or drop.
• Liquid/Dust Contact Risk: Due to the crack, the interior of the device has become exposed to external factors. Dust accumulation or liquid contact with internal electronic boards is probable.
• Repair Requirement: The product’s outer casing must be replaced or repaired for it to be safe for professional use.

Accessories and Missing Items

In the analyzed visuals, the connection cable for connecting the device to the main unit, electrode sets, or any sensor cables are not visible. Only the input box (unit body) is present.

Originality Status

Upon examining the product’s panel design, text characters, material quality (plastic molding), logo printing, and craftsmanship at connection points, the product is assessed to be an original NIHON KOHDEN equipment.