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* "TV Mini-SEM (R)" by ISI (International Scientific Instruments)
* "TV Mini-SEM (R)" by ISI (International Scientific Instruments)
* lives in the room that used to house the laser cutter
* lives in the "science ghetto" on the west end of the south wall at 2169.
* is tended by Alan Rockefeller, Jeff Miller, Chris Murphy and Jim and the rest of the [https://www.noisebridge.net/mailman/listinfo/sem SEM mailing list]
* is tended by Mike Kan and the rest of the [https://www.noisebridge.net/mailman/listinfo/sem SEM mailing list]


=== Warnings ===
=== Warnings ===
# 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 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). The filament has a design lifetime of about 25 hours, depending on the current put through it. Adjust the specimen stage and other controls at low current, reserve higher currents for final photos.
# If you vent air into the column without powering down the filament, you'll probably destroy the filament ($100).
# Mike Kan has warned that if anyone asks him anything about the SEM, he's going to move it to another hackerspace. Jeff Miller has a MinI-SEM of his own, and knows its ins and outs pretty well.
# If you


=== Startup procedures ===
=== Startup procedures ===
# If the power cord is not already present, ask around or post to the list a few days prior to using the 'scope.
# get the power cord from Mike.
# See PDFs on vacuum start up and operators manual linked below.
# (to be continued)


=== Todo list ===
=== Todo list ===
Short Term:
# column liner needs to be replaced. Larry may be able to provide a clean liner. (2010-06-15)
# Isolate vibration from external sources; buses, people, etc. Mostly finished. (2013-6-20)
# (long term) build digital capture stage to replace CRT mechanism (2010-06-15)
# Figure out what to do about the person(s) now "occupying" the clean room which houses the SEM. (2013-6-20)
# build sputter coater for specimen preparation (2010-06-15)
# Design/build/find a sputter coater so the SEM can be used as a useful tool as well as a curiosity.
# test repair of X Stigmator circuit. Replaced 741 op amp. (ongoing, work began 2010-11-20)
# Create/obtain specimen stage clamp or spring to prevent specimen vibration. (2010-12-12)
# Obtain some sputter coated specimens. (2010-12-12)


Medium Term:
=== Repair and Enhancement ===
# Build a forepump line vibration isolator. (2013-6-20)
# Relocate or otherwise isolate the forepump. (2013-6-20)
# Replace most of the rubber tubing with metal tubing to reduce outgassing and pump-down times. (2013-6-20)
 
Long Term:
# 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)(update: column liner is now clean) (2013-6-20)
# Integrate the digital capture and control unit Jeff built for his own Mini-SEM into the unit. (2013-6-20)
# 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). Sew/heat seam new plastic dust cover, evidently the previous dust cover was destroyed. (2013-6-20)
# Rubber grommet around edge of CRT potentiometer port needed.
# Replace forepump with a (hopefully larger) pump that has a ballast port.
# Buy/find some real vacuum valves, turn simple spool pieces to serve as adapters, and electro-pneumatically interlock the valves so that valve sequencing is fool-proof.
# Evaluate air-cooled diffusion pump as source of vibration and contamination. Consider Santovac fluid and/or water-cooled pump and/or thermoelectric cold cap.
# Consider replacing filament with LaB6 cathode for brighter, sharper images and lower long-term per hour operating costs.
 
=== 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
* 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.    
* poorly designed wire harness may cause linear op amp and transistor on the J1 board of the CRT 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)
* 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.


=== Specifications ===
=== Specifications ===
* Made in Japan
* Delivered in September, 1975
* Delivered in September, 1975
* magnifies up to 20,000x
* magnifies up to 20,000x (reliably up to 700x in its present condition)
* outputs to a CRT
* outputs to a CRT
* non-digital, non-NTSC, non-PAL, analog output signal
* non-digital, non-NTSC, non-PAL, analog output signal
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[[Media: Other_Docs.pdf]] - Repair notes
[[Media: Other_Docs.pdf]] - Repair notes


[[Media: Packing_Lists.pdf]] - Original Packing Lists, the contents of the shipping crate
Original Packing List - coming soon


=== Schematics ===
=== Schematics ===
 
[[Media: Polaron_Pirani_Gauge_Head_for_Sputter_Coater.pdf]]
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 [http://hugin.sourceforge.net/ 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:
[[Media: TV_MINI-SEM_Schematics-Overall_MRS-2-2_WN76-7-01_Mosaic_v._1.0_Low-Res.jpg | LOW RES 1.5MB (4330 x 3109, posterized grayscale, JPEG)]] and
[[Media: TV_MINI-SEM_Schematics-Overall_MRS-2-2_WN76-7-01_Mosaic_v._1.0.jpg | HIGH RES 8MB (8680 x 6217, color, JPEG)]].


[[Media: Schematic_of_Photomultiplier.pdf‎]]
[[Media: Schematic_of_Photomultiplier.pdf‎]]


[[Media: Polaron_Pirani_Schematics-PE_Pir-SW_Issue_4_E5000.pdf]] - Polaron Pirani sputter coater schematics
Full schematics of the SEM - coming soon
 
[[Media: Polaron_Pirani_Gauge_Head_for_Sputter_Coater.pdf]]


=== Specimen Images ===
=== Specimen Images ===
 
[[Image:IMG_0004.jpg|thumb|left|Image of mechanical pencil graphite on an aluminum slug at approximately 20x magnification. The specimen is about 1 mm across. Higher magnification images of this specimen are not available. Imaged by Chris Murphy and Mike Kan.
<gallery widths=200px heights=166px>
]]
Image:IMG_0004.jpg|Image of mechanical pencil graphite smudge on an aluminum slug at approximately 20x magnification. The specimen is about 1 mm across. This is prior to repairing the X Stigmator. Magnification was limited. Imaged by Chris Murphy and Mike Kan.
 
Image:IMG_0652.jpg|Mechanical pencil graphite smudge on aluminum slug. 1000x magnification. This is post repair of X Stigmator. Imaged by the Noisebridge SEM. Mike Kan, Chris Murphy.
 
Image:IMG_0655.jpg| Tip of mechanical pencil graphite  on aluminum slug. 500x magnification. This is post repair of X Stigmator. Imaged by the Noisebridge SEM. Mike Kan, Chris Murphy.
 
Image:IMG_0654.jpg| Tip of mechanical pencil graphite on aluminum slug. 1000x magnification. This is post repair of X Stigmator. Imaged by the Noisebridge SEM. Mike Kan, Chris Murphy.
 
Image:IMG_0656.jpg| Tip of mechanical pencil graphite on aluminum slug. 5000x magnification. This is post repair of X Stigmator. Imaged by the Noisebridge SEM. Mike Kan, Chris Murphy.
 
Image:IMG_0657.jpg| Tip of mechanical pencil graphite on aluminum slug. 10,000x magnification. This is post repair of X Stigmator. Specimen was moving on the slug due to mechanical vibration. Imaged by the Noisebridge SEM. Mike Kan, Chris Murphy.
 
Image:IMG_0624.jpg|Semiconductor ball grid array at 20x magnification prior to repairing the X Stigmator. Mike Kan, Chris Murphy
 
Image:IMG_0649.jpg|Snapped metal region of a box cutter razor blade. Imaged on the Noisebridge SEM. About 5000x magnification. This is post repair of X Stigmator. Mike Kan, Chris Murphy
 
Image:IMG_0007.jpg|Head of a small 2mm allen type machine screw. Less than 1000x magnification. This is post repair of X Stigmator. Mike Kan, Chris Murphy
 
Image:Allen_close_up.jpg|Head of a small 2mm allen type machine screw. About 1000x magnification. This is post repair of X Stigmator. Mike Kan, Chris Murphy
 
Image:IMG_0026.jpg|Diatom imaged in fast scan mode (lower resolution than slow scan photo mode). Magnification unrecorded. Mike Kan, Chris Murphy. 12/12/10
 
</gallery>
 
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