Condition: Used – Professional Laboratory Surplus / Vintage Analytical Asset - UNTESTED
This is a highly rare, custom-integrated laboratory configuration from Cambridge Scientific Instruments Limited (England), built specifically for the legendary Stereoscan 600 Scanning Electron Microscope (SEM).
The heart of the unit is a high-precision Keithley Instruments Model 427 Current Amplifier, factory-modified and front-panel branded as the dedicated Cambridge 600 S.C.A. (Specimen Current Amplifier) system. It is accompanied by its rare, custom-matched top-mounted companion routing/preamp switch box featuring dedicated manual signal toggle controls ("IMAGE / S.C.A.").
In historical SEM workflows, this exact hardware array was responsible for collecting, stabilizing, and boosting the ultra-faint pico-ampere absorbed currents coming off microscopic samples under electron beam bombardment, allowing researchers to generate high-resolution surface and defect imagery.
System Brand: Cambridge Instruments / Keithley Instruments, Inc.
Component Models: Unified Model 427 Base Engine + Custom Matching S.C.A. Routing Box
Serial Number: 32440 A
Gain Selection Ranges: 8 decade steps spanning from 10^4 to 10^11 Volts/Ampere
Rise Time / Bandwidth Controls: Variable internal filtering adjustable from 15 µs (DC to 30 kHz tracking) up to 330 ms for maximum background noise suppression.
Front Panel Configuration: BNC Signal Input, Manual Suppression Pots, Overload & Power Indicators, Dedicated Rise Time and Gain dials.
Rear/Top Interface Connectivity: Hardwired multi-point inter-modular umbilical signal cable assembly (as pictured) with active rear output links.
Mains Power Input: Configured for UK Mains (Set to 234V). Features a dual-voltage switch-selectable internal transformer design (117V / 234V) operating at 50–60 Hz.
Fuse Requirements: Standard 3AG Slow-Blow fuse footprint (1/8A currently utilized for safe 234V UK operations).
Total Combined Weight Approx: 4.2 kg (Including top-mounted routing module and interface cables)
Main Unit Width: 21.7 cm (Standard 3½” laboratory half-rack width format)
Main Unit Height: 10.0 cm * Main Unit Depth: 31.0 cm * Top Box Dimensions: 11.5 cm x 4.5 cm x 26.5 cm
Completeness: Uniquely preserved with its hard-wired interconnecting leads, original control dials, and matching switcher box, making it an excellent replacement line or static exhibition asset for historical computing/microscopy restorations. This set is untested.
Cosmetic Condition: Exhibits typical dust, and aging consistent with long-term placement in a laboratory store room environment as well as some areas of superficial rust. Faceplate text and dial markings remain clean and legible.
Postage: Please allow up to 6 days for shipping and dispatch. Contact prior to purchase if required sooner.
Collection: Collection in person is also welcome from Warrington (WA3).
Note: For collections, please contact us following the sale to arrange a suitable time slot.