The Scanning Electron Microscope at Noisebridge.
- "TV Mini-SEM (R)" by ISI (International Scientific Instruments)
- lives in the "science ghetto" on the west end of the south wall at 2169.
- is tended by Mike Kan and the rest of the SEM mailing list
- If you release the vacuum without venting the pump hose, pump oil will flood the chamber and contaminate the entire mechanism, requiring 10 hours of cleanup.
- If you vent air into the column without powering down the filament, you'll probably destroy the filament ($100).
- Get the power cord from Mike.
- See PDFs on vacuum start up and operators manual linked below.
- Isolate vibration from external sources; buses, people, etc. See Repair and Enhancement notes below. (2010-12-12)
- Create/obtain specimen stage clamp or spring to prevent specimen vibration. (2010-12-12)
- Obtain some sputter coated specimens. (2010-12-12)
- Column liner needs to be replaced. Larry may be able to provide a clean liner. (2010-06-15) (update: Larry has taken column liner to his lab for cleaning)
- Build digital capture stage to replace CRT mechanism (2010-06-15)
- Replace 8.4" slow scan CRT with slow scan XGA LCD? (see above)
- Build sputter coater for specimen preparation (2010-06-15)
- Test repair of X Stigmator circuit. Replaced 741 op amp. (completed, work began 2010-11-20, tested 2010-12-10)
- Adjust vertical overscan of CRT (completed 2010-12-12, including hack sawing access port to overscan potentiometers in the CRT module)
- Fix 2x magnification toggle switch (2010-12-12)
- Diagnose and repair barrel distortion and occlusion at low magnification (2010-12-12)
- Sew dust cover (2010-12-12)
- Rubber grommet around edge of CRT potentiometer port needed
Repair and Enhancement Notes
- Before repair, disable pumps and high voltage then put it into operation mode by placing a magnet on the operation relay.
- schematics framed behind SEM are to a similar, potentially slightly more modern model
- poorly designed wire harness may cause linear op amp and transistor on the J1 board of the power module to fail.
- camera mounting stage and bellows hood for slow-scan exposure. Proposed (2010-06-15), Completed by Mike, Miloh, and Chris (2010-11-06)
- CRT V. scan, V bias, H. frequency potentiometers are located on the underside of the CRT module.
- broken stigmator Y lock tab is in altoids tin in SEM kit box.
How to mitigate vibration:
- Measure and pinpoint vibration sources
- Dampen vibration from the rough pump-line by one of these methods: routing it through a concrete block and adding a hose extension, sandbag the existing line, or utilize water as a mass.
- Hang the column from the ceiling with bungee cord and platform
- Potentially relocate the microscope to the server room to diminish dust and increase distance from Mission St.
- Create spring clamping specimen slug to keep the specimen from moving.
- Made in Japan
- Delivered in September, 1975
- magnifies up to 20,000x
- outputs to a CRT
- non-digital, non-NTSC, non-PAL, analog output signal
Media: Vacuum_System_Operating_Instructions.pdf - How to start the pump
Media: ISI_Mini-TV_SEM_Manual-Troubleshooting-Reference_Guide.pdf - How to use and fix the SEM
Media: Specimen_Stage_Service_Request.pdf - Why the rotating stage is broken
Media: Cards.pdf - Historic docs
Media: Other_Docs.pdf - Repair notes
Media: Packing_Lists.pdf - Original Packing Lists, the contents of the shipping crate
Overall schematics for the TV MINI-SEM (Model: MRS-2-2 WN76-7-01). These schematics are for a model of SEM that is perhaps newer than than the SEM at Noisebridge. It is still an invaluable reference to the technician. Note: This schematic is a mosaic of 9 images stitched together with Hugin 2010.2.0. Some minor alignment issues exist in the content of the schematic. I think alignment can be guessed/interpreted accurately. Available in: LOW RES 1.5MB (4330 x 3109, posterized grayscale, JPEG) and HIGH RES 8MB (8680 x 6217, color, JPEG).
Media: Polaron_Pirani_Schematics-PE_Pir-SW_Issue_4_E5000.pdf - Polaron Pirani sputter coater schematics