Thermo Fisher Scientific NX50 Cryostat
Thermo Fisher Scientific · Model NX50 Cryostat
Cryobar holds 18 freezing stations and one fast freezing station Constantly cooled chamber at a temperature of -25°C+/-2°C at ambient temperature of +20°C Constantly cooled knife holder at a temperature of -27°C to -20°C +/-2°C at 20°C to 30°C ambient Active Object head cooling -43°C+/-2°C at 20°C ambient. The object head temperature can be user defined Integrated Peltier fast-freezing device -57°C +/-3°C at 20°C ambient with separate cooling element (single position) Sliding glass door with integrated LED lighting Choice of immediate or scheduled defrost cycle Color coded specimen chucks help to identify specimens.
Typical Failure Modes
Compiled for this model from its own documentation and established engineering knowledge for this equipment class - not from a verified service record. Confirm against the manufacturer's service manual.
Chamber will not hold set temperature
HighSymptoms: Chamber warmer than -25 C, long pull-down time, frost buildup, poor section quality.
Root cause: Refrigeration compressor wear, low refrigerant charge, condenser fouling, or failed chamber door seal.
Peltier fast-freeze / object-head cooling weak
MediumSymptoms: Fast-freeze station or object head fails to reach spec (-43 to -57 C), specimens freeze slowly.
Root cause: Degraded Peltier module, dried thermal interface, or a failing Peltier driver.
Microtome advance / handwheel fault
MediumSymptoms: Uneven section thickness, skipped sections, coarse/fine feed not tracking, mechanical noise.
Root cause: Worn micrometer feed mechanism, contamination in the cross-roller slide, or backlash in the advance.
Automatic defrost / condensate handling failure
MediumSymptoms: Excessive ice on the evaporator, water pooling, chamber temperature swings, drain overflow.
Root cause: Defrost heater or timer fault, blocked condensate drain line, or full evaporation tray.
Sliding glass door / LED illumination fault
LowSymptoms: Door binds or does not seal, chamber light out or flickering.
Root cause: Worn door track/rollers or gasket; failed LED strip or its driver.
Serviceable Parts & Consumables
Serviceable items for this model, compiled from its documentation and engineering knowledge for this equipment class. Service class and relative cost are estimates, not manufacturer figures; no part numbers are given. Confirm intervals and pricing against the manufacturer.
Chamber door gasket / seal
Class Periodic replacementRel. cost $$R&R Fairly easy
Refrigeration compressor
Sealed-system work; requires refrigeration certification.
Class Major service partRel. cost $$$$R&R Expert-level
Peltier module (fast-freeze / object head)
Class Major service partRel. cost $$$R&R Difficult
Microtome micrometer feed assembly
Class Major service partRel. cost $$$R&R Difficult
Defrost heater and thermostat
Class Major service partRel. cost $$R&R Moderate
Chamber LED lighting strip
Class Major service partRel. cost $R&R Fairly easy
| Part | Service class | Relative cost | R&R difficulty |
|---|---|---|---|
| Chamber door gasket / seal | Periodic replacement | $$ | Fairly easy |
| Refrigeration compressor Sealed-system work; requires refrigeration certification. | Major service part | $$$$ | Expert-level |
| Peltier module (fast-freeze / object head) | Major service part | $$$ | Difficult |
| Microtome micrometer feed assembly | Major service part | $$$ | Difficult |
| Defrost heater and thermostat | Major service part | $$ | Moderate |
| Chamber LED lighting strip | Major service part | $ | Fairly easy |
Relative cost: $ lowest · $$$$ highest service-part cost for this equipment class. Not a price.
Troubleshooting Approach
A starting sequence for this model, compiled from its documentation and engineering knowledge for this equipment class. Follow the manufacturer's service documentation for the actual procedure.
Symptom: Chamber not reaching or holding temperature
- Confirm the set point and that the door seals fully; inspect the gasket for compression set and tears.
- Check the condenser and filter for dust and clean; verify the condenser fan runs.
- Measure pull-down rate and compare to spec; a slow, steady rise points to seal/door, a fast rise to a sealed-system fault.
- If sealed-system pressures are out of range, escalate to a refrigeration technician for charge / compressor evaluation.
- Verify stable temperature over a full cycle and a clean test section before releasing.
Symptom: Poor or uneven sections
- Rule out a dull or wrong-angle blade and incorrect clearance angle first.
- Check chamber and knife-holder temperature against spec for the tissue type.
- Cycle the coarse and fine advance through full travel, feeling for backlash or binding.
- Clean the cross-roller slide and specimen head; re-check anti-roll plate alignment.
- Cut a test block and confirm consistent thickness before returning to service.
Documents & Manuals
Safety & Recalls
Synced live from the FDA openFDA API.
- RECALL
Through internal quality review, firm determined the need to conduct a more comprehensive system validation to support the claim of complete bacterial, fungal and viral disinfection efficacy.
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