# JSM 5600 #publish >Navigation: [[JEOL]], [[Electron Microscope MOC]] Year: ~1997 Technology Synopsis: - PC to microscope over SCSI - SCSI to frame store sub system. Frame store has RS 485 transducer for the microscope control and feedback data bus. - Video to PC over capture card - Microscope control and feedback data bus is a custom sudo [[token ring]] topology - Optics subsystem uses its own dedicated 8 bit address-data buss ## Vacuum Pump The 5600, like many SEMs from JEOL around this time, shipped with a [[Ulvac G-100 Series Rotary Vacuum Pump]] ## Reference Pictures [[JEOL 5600 Scintilator Reference Pictures]] ## Troubleshooting ### Does not exit Pre-Evac Made for a specific fault that turned out to be a RP failure to reach 26 Pa. Useful for many other SEMs that use similar vacuum systems. ![[JSM 5600 Vacuum Sequence Pre Evac Hold Diagnostic Fault Tree.excalidraw.png]] ### V4 or VV1 does not properly actuate V4 and VV1 are the largest valves in the microscope's vacuum system. They need to be large because they connect the diffusion pump to the rest of the microscope, and if they were any smaller conduction through them would be limited. Driving large valves close to the chamber or column of an electron microscope presents some unique challenges. Electromagnetic solenoid valves cannot be used because the magnetic field they create can interfere with the electron beam. JEOL has frequently used pneumatic valves for this and other reasons. However, in an effort to simplify facility requirements the 5600 and other similar microscopes use no compressed air system. In lieu of compressed air, JEOL uses the roughing vacuum pump to pneumatically actuate the valve. When V4 or VV1 is to be opened, its corresponding solenoid, V7 or VV4 respectively, is energized. When energized, the actuating solenoid connects the valve cylinders to vacuum, pulling the valve open. When de-energized, the valve cylinders are vented to atmosphere. V4 and VV1 have springs that return the valves to the closed position when V7 or VV4 are de-energized. VV1 in particular has a proximity sensor that can detect if the valve is in the fully open position. If the proximity sensor is not activated the vacuum sequence may not proceed. The solenoid used for V7 and VV4 is prone to failure with age. They should be inspected thoroughly whenever there is a problem with V4 or VV1. One possible failure mode is that the rubber inside of the valve gets hard and it no longer seals properly. Because V7 is a 3 way valve, symptoms include but are not limited to: - Not actuating at all - Partially actuating and staying in an intermediate state between NO and NC - Air leaking from the NO (air) side to the COM or NC sides (this can cause a general failures to start up properly) - this is usually caused by the rubber valve seat getting hard I have diagnosed leaking solenoid valves by placing a gloved finger or stopper over the NO port of the valve. If you feel a vacuum being pulled under your glove, or if the microscope vacuum sequence starts moving again, that solenoid valve should likely be replaced. These solenoid valves leaking can also cause the chamber or buffer tank pump down cycle to not complete. If this is suspected, monitor PI4 (chamber)/PI2 (buffer tank) pressure while blocking off the NO side of the valve with a glove or stopper. If pressure drops when NO port is covered, the solenoid valve is leaking. Take care when doing this as interfering with pump down sequences can cause other problems. You can test for power going to the valves with a multimeter. When the LED for the valve is lit up on the vacuum control board, you should see ~24VDC on across the black and red wires going to the valve. When replacing V7 and VV4, we have had success substituting locally available off the shelf 3 way 2 position 24VDC solenoid valves. See picture below, the turquoise solenoid valve is one we sourced from a hardware store (Grainger) down the street from this particular lab. ![[CleanShot 2024-04-18 at [email protected]]] ![[Pasted image 20240418145809.jpg|lg]] #### Later model JEOL SEMs using a similar valve architecture. V4 on later JEOL model SEMs (Example 6460). Note additional valves V9 and V11 and new buffer tank RT2. The addition of V11 allows the valve to be vacuum actuated in both the open and closed direction. This eliminates the reliance on a spring to close V4 when V7 is de-energized. The buffer tank (in JEOL speak known as a roughing tank) allows for V4 to be actuated without exposing the rest of the vacuum system to a sudden increase in pressure. It also allows for V4 to be actuated when RP1 is being used to do something else, like pumping down the buffer tank attached to the diffusion pump. ![[CleanShot 2024-04-18 at [email protected]|lg]] ## Schematics ![[5500-5500LV 5600-5600LV Circuit Diagrams Reduced.pdf]]