| A word of caution about the gratings: Reported **problem**, "I found that the monochrometer seems to be having trouble. I tried to reset it to 518 nm and found that thanks to what seems to be a belt problem, it is stuck at 926 nm", David Mc **responded** on (9/12/21), "I (kind of) fixed the spectrometer. I know what the problem was, but I do not know what caused it. BUT, YOU should figure out what caused the problem, as it has damaged the instrument already and if it happens again it may further damage the instrument. | A word of caution about the gratings: Reported **problem**, "I found that the monochrometer seems to be having trouble. I tried to reset it to 518 nm and found that thanks to what seems to be a belt problem, it is stuck at 926 nm", David Mc **responded** on (9/12/21), "I (kind of) fixed the spectrometer. I know what the problem was, but I do not know what caused it. BUT, YOU should figure out what caused the problem, as it has damaged the instrument already and if it happens again it may further damage the instrument. The indicators on the 2 spectrometers read the wavelength in the range 0-999. But what they are really doing is indicating the angle of the grating, which is turned with the sets of gears and pulleys. The indicator that was at 926 nm had arrived at that point not by going from 518 nm up to 926 nm, but rather by going from 518 nm, down to 0 and thorough 0 (to the negative side) and stopping at 926. Thus the grating was at an angle where no light goes through the spectrometer. The spectrometer is not designed to go past 0, so the gears and belts locked up. By removing some belts and applying gentle but firm force, I was able to independently get the 2 spectrometers back into the “positive” region. With the coupling belt removed, I set one spectrometer to 518 and then adjusted the other by monitoring the spectrometer output. The output was maximized with the second spectrometer (closer to the lamp) set to 545 nm. This indicates that the gears and belts slipped quite a bit. Unfortunately, now we do not know which dial, if either, is correct. The system needs to be recalibrated. Moreover, the gears appear to slip during a manual scan and this may cause problems for a computer controlled scan." |
| The indicators on the 2 spectrometers read the wavelength in the range 0-999. But what they are really doing is indicating the angle of the grating, which is turned with the sets of gears and pulleys. The indicator that was at 926 nm had arrived at that point not by going from 518 nm up to 926 nm, but rather by going from 518 nm, down to 0 and thorough 0 (to the negative side) and stopping at 926. Thus the grating was at an angle where no light goes through the spectrometer. The spectrometer is not designed to go past 0, so the gears and belts locked up. By removing some belts and applying gentle but firm force, I was able to independently get the 2 spectrometers back into the “positive” region. With the coupling belt removed, I set one spectrometer to 518 and then adjusted the other by monitoring the spectrometer output. The output was maximized with the second spectrometer (closer to the lamp) set to 545 nm. This indicates that the gears and belts slipped quite a bit. Unfortunately, now we do not know which dial, if either, is correct. The system needs to be recalibrated. Moreover, the gears appear to slip during a manual scan and this may cause problems for a computer controlled scan." | |
