During a failed attempt to observe and photograph the Camelopardalids meteor shower, I found out that the finderscope of the 4SE was not working. If you have not done this, try doing it, it is ridiculously hard to successfully aim the telescope at anything if your finderscope is not working.
After testing with multiple batteries, my immediate worry was that the LED in the finderscope may have burnt out. If this was the case it would be quite hard to fix it. That's when I decided to dismantle the finderscope to pinpoint what exactly went wrong.
Removing the finderscope from the telescope is quite easy. You need to unscrew the two bolts on the side of the finderscope, just under the switch and the calibration screws.
Once done, you need to remove the unscrew the calibration screws themselves.
You need to hold the calibration screw with one hand and unscrew the bolt. The calibration screw will otherwise turn along with the bolt.
And this is what the inside looks like:
The brightness controlling screw is a mechanical latch and a variable resistor connected together. The red piece you can see in the image works as a latch that keeps a circuit open. When you turn the brightness controller the latch drops and the circuit completes.
Further turning the brightness screw changes the resistance of the variable resistor, thus changing the brightness.
As it turned out, the problem was in the brightness screw. I think the continuous turning of it may have worn it out and the circuit wouldn't complete through the variable resistor.
Solution: Short circuit the variable resistor.
Note: It is not recommended to do this on your own unless you are ready to accept the consequences. Tampering with the devices will automatically void the warranty from the manufacturer. As it turned out, my hand slipped while soldering the short circuit wire and the plastic latch that keeps the circuit open got burnt. Now the finderscope is in an "always on" state where you have to remove the battery to turn it off.
Note 2: It is not recommended to unscrew the calibration screws too often. They could easily wear out and you will not be able to adjust/calibrate the finderscope afterwards.
After testing with multiple batteries, my immediate worry was that the LED in the finderscope may have burnt out. If this was the case it would be quite hard to fix it. That's when I decided to dismantle the finderscope to pinpoint what exactly went wrong.
Removing the finderscope from the telescope is quite easy. You need to unscrew the two bolts on the side of the finderscope, just under the switch and the calibration screws.
Once done, you need to remove the unscrew the calibration screws themselves.
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And this is what the inside looks like:
The brightness controlling screw is a mechanical latch and a variable resistor connected together. The red piece you can see in the image works as a latch that keeps a circuit open. When you turn the brightness controller the latch drops and the circuit completes.
As it turned out, the problem was in the brightness screw. I think the continuous turning of it may have worn it out and the circuit wouldn't complete through the variable resistor.
Solution: Short circuit the variable resistor.
Note: It is not recommended to do this on your own unless you are ready to accept the consequences. Tampering with the devices will automatically void the warranty from the manufacturer. As it turned out, my hand slipped while soldering the short circuit wire and the plastic latch that keeps the circuit open got burnt. Now the finderscope is in an "always on" state where you have to remove the battery to turn it off.
Note 2: It is not recommended to unscrew the calibration screws too often. They could easily wear out and you will not be able to adjust/calibrate the finderscope afterwards.
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