Category Archives: JEOL Maintenance

Mainteance information on JEOL EPMA

JEOL Maintenance

Replacement of OpAmp (CA3030A) in ORTEC 490J/490JA AMP SCA

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Main OPAMPs (IC1 and IC2) might be damaged if the output voltage of IC1 or IC2 differs from a typical value in the manual. Furthermore, you can observe signals around OPAMPs.

Typical waveforms of 490J/490JA.

CA3030A has been discontinued, and it is not easy to obtain it. CA3030A can be electronically replaced with a modern OPAMP, keeping compensation pins unconnected. However, its pin configuration differs from that of a modern single OPAMP. A TO-99 metal might be usable for replacement, but a TO-99 package is also uncommon now. Therefore, I made the conversion PCB to use the standard 8-lead SOIC package OPAMP.

CA3030A to SO8 OpAmp conversion PCB.
Schematic

CA3030-SO8-CONV_Gerber.zipGerber files

I soldered IC sockets. Therefore, the conversion module is replaceable.

JEOL Maintenance

Unstable electron optical system

When you get an unstable beam current, please check the
three components: +80V 1.5A, +75V 7.5A, and AL-02J in the EOS unit.

+80V 1.5A and +75V 7.5A (HV and CL/OL supplies)

The first step is to check the output voltage between check terminals. If the output voltage is incorrect, adjust it by VR1. Also, if the output voltage is unstable, you need to repair the PSS module. The easiest way is to replace all electronic parts on the PCB. You need to use 1/2W or grater registers instead of the original 1/4W registers when replacing the PSS components. The simulation shows the power consumption of those registers is more than 300 mW.

 

AL-02J (ALIGN coils and STIGMATOR)

I guess that insufficient thermal design may damage transistors on the AL-02 module. If this module’s output is unstable, you can replace transistors mounted on the heatsink (TO-220 package). Please apply high-quality thermal grease.

JEOL Maintenance, Maintenance

RLV12 RL01/RL02 Controller damage

Some JCXA-733/JCMA-733 were shipped with the DEC RLV12 RL01/RL02 controller and RL drives. I saw many damaged the RLV12 installed in JCXA-733/JCMA-733 systems. Once the RLV12 is crashed, it is impossible to access any RL drive. The ZRLBC0 diagnostic program shows the MAINTENACE SEQUENCE failure. As far as I remember, all damaged RLV12 was located above the QNIVERTER. So, I guess the damage is caused by the order of modules in the Q-bus backplane.

Bandade

I placed the RLV12 controller bellow the QNIVERTER as showed in the figure.

JEOL Maintenance

[MOD][FIX] 35-DMA read error

The 35-DMA unit, digital micro ammeter, sometimes causes read error and read value becomes 0. That is, the MA register sometimes becomes 0 after executing the L DMA command. The +5V line near the Tr 14 sometimes drops its voltage when the PRINT ADVANCE signal turns into active. Then, the PRINT ADVANCE signal apparently becomes active again when the voltage drop happens.

 

Two capacitors, connected to the PRINT ADVANCE signal solve this problem.

[MOD] fix timing problem of 35-DMA

JEOL Maintenance, Maintenance

[MOD] Improve safety of SMD

The power of the stepping motor driver (SMD) is controled by the host computer via the cable from CN2 to SGMD2 (STAGE) or SPMD2 (spectrometer).

 

AC100V is applied to this cable, and I think it is danger, especially when the cable and/or relay on the OCX module are damaged.

 

The following modification applied DC24V instead of AC100V to control the power of the SMD unit.

 

733-SMD-mod

 

The AC-DC converter generates DC24V and it is applied to control the DC24V relay, replacing original AC100V relay.

 

I believe this improves safety.

JEOL Maintenance

JEOL stage gear head repairment

Degration of the gear head(s) of the stage causes large backlash and makes stage positioning inaccurate. Main problem is wear of the clutch part of the gear head unit. It can be fixed by yourself as the procedure below.

Types of JEOL gear head

There are two types of the JEOL stage gear head.

 

733-Gearhead-types

Step 1: Check backlash
Move gears by hands to check backlash. Gears should not have backlash. If gears have backlash, even small movement, the clutch part needs to be maintained.
Check gears movement
Step 2: Remove the cover
Remove three screws and the cover.
733-Gearhead-Step1
Step 3: Disassemble
Remove three screws and disassemble the gear head.
733-Gearhead-Step2
733-Gearhead-Step3
Step 4: Cleaning
Clean up all parts using acseton with ultrasonic cleaner.
Step 5: Fix clutch (1)
Apply small amount of epoxy resin adhesive to the cluch pin.
733-Gearhead-Step5
Step 6: Fix clutch (2)
Insert the gear and remove it to put small amount of epoxy resin adhesive on the clutch slit. Then, wait.
733-Gearhead-Step7
Step 7: Adjust clutch
Insert and remove the gear to adjust movement of the clutch system.
733-Gearhead-Step6
Step 8: Assemble
Assemble the gear head unit, applying suitable grease.
733-Gearhead-Step9
Step 9: Check
Check movement of gears and the clutch.
733-Gearhead-FinalCheck