[Noisebridge-discuss] Electron Microscope - Service update and status - Some messages were mirrored as e-mail messages

[Michael Kan Kan]

To all of tne SEM.


 Found that theoil from the roughing - backing pump had sucked back to the
column and contaminated the diffusion pump. This was remedied. This happend
a second time which the pump oil got sucked back into the instrument about
20 hours after the first fix. Pressed the foreline vent button sevaral times
and over a few days apart. Seems that even after that, there was enough 
vacuum that the the oil was sucked back up again.in the morning of May 6
 Did the repair again. This, Did not know that the flooding went to
the specimen chamber.
 Tried to run the instrument on May 26 and there was some crackling sound
from the display. there did not seem to be any usable image and this
dashed noise across the screen. Checked to see that it was comming from the
scntilator disk and vented the specimen chamber and found that it was
like the gulf.
 Cleaned the chamber andresumed to use the instrument.
 the dashed screen noise was gone and could gradual vertical bars that
would follow stage movent and various other adjustments.

 Then did a bean check to see where the scan raster was.
 Found that the scanning circuits had been damaged by the electrical 
flashover,
 One axis was partialy functionalbut it would move off the specimen
when magification was decreased ( Greater size raster on subject ).
 There wass only a line showing that the other axis scanis absent.

 Having to wait for the rest of the instrument to build a vacuum to
check the scanning circuit seem to take too much time.

 So the high vacuum and voltage was temporarly defeated and a magnet
was placed on the ready light and operating relay wo that the scanning
circuits could be trouble shooted more interactivly.

 There is currently signals going into the scan amplifier but nothing
comming out.

 So does any body know if there are any 16 pin DIP 741 OP-AMPs around?

 I have come to Noisebridge for people. Chris Murphy assisted me from
3 PM on Wednesday 26 till 6AM Thirsday 27 
 Mostly converted a audio cassette player to a signal tracer to do wire
tracing.  Came back around noon to configure the instrument to safe but
non functional mode to better trouble shoot the scanner circuits.


 would like to have others of this group present to help keep me company
and learn how to matain and repair the microscope.


Take care

 Mike Kan