I am beginning the dismantling process of this scope. Based on notes from last year, I am suspicious that CR1541 has failed. I will not power up the scope
because I am not equipped to safely work with high voltages. I need to remove the lower board in order to access the solder side of the board. I have a soldering iron tinned with 60/40 tin lead solder that is specifically assigned to this project.
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| Figure 01-A: Lower board with HV shield attached. CR1541 is in the far upper right corner. |
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I removed the HV shield and replaced the screws in their respective holes. I preserved the unique location of each screw.
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| Figure 01-B: Lower board with HV shield removed. |
After removing the HV shield, I removed dust using cotton
tipped applicators and then used the cotton to polish the capacitors and surrounding components. I was careful to not apply fingerprints to the components which could otherwise affect conductivity across the exterior of the components.
In Figure 01-C, note the blue wire passing through the board. Adjacent to this blue wire is a solder post secured by a machine screw/nut assembly. This post also attaches a gray wire that goes to the 115/230 voltage selector switch.
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| Figure 01-C: Note blue wire adjacent to machine nut. |
In Figure 01-D, I de-soldered the blue and gray wire and replaced the post into it's mounting location.
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| Figure-01-D: The two wires are de-soldered and dislodged from board. |
In Figure 01-E, the knobs for INTENSITY, FOCUS, SCALE ILLUM, POSITION and A TRIG HOLDOFF are loosened. I carefully and fully seated a 1/16" hex driver in the hole and incremented pressure until the screw rotated. The screws loosened without issue to allow the knobs to remove.
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| Figure 01-E: 1/16" hex driver used to loosen set screws |
Note in Figure 01-F that the POSITION knob is unique on this scope and can adjust two dimensions. There are two set screws on this assembly.
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| Figure 01-F: Two set screws on this unique knob. |
There are matching set screws on the variable components in Figure 01-G. These set screws are loosened, the connecting rods removed and screws are re-tightened to to retain them from loss. The documentation quotes "SETSCREW:4-40 X 0.188 INCH,HEX SOC STL" which provides the outer dimensions, but suggests nothing on the hex wrench needed. A T5 Torx marginally did the job, this time."
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| Figure 01-G: Set screws of unknown dimension on variable components. |
