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Fisher Fischer Scientific 225 Cat 04-978-50 Centrific Centrifuge W/221 Rotor & Manual Centrifuge Questions & Answers
How to deduce the centrifugation speed from the scale provided?
Do you have a biomedical group in your facility or somebody who's responsible for maintaining your equipment? If you do, they should have a photo-tachometer. They can place a piece of reflective tape onto the rotor to get you the true rpm speed. You probably need an accurate speed anyway to ensure proper rcf for your samples.
Fischer Scientific AB15 -- Unable to calibrate or take any readings.
The electrode you have is a combination electrode with an integral calomel reference half-cell and built-in temperature probe. Since the temperature reading is good, the temperature probe is okay. It isn't part of the pH circuits anyway. (Your meter uses the temperature to calculate a temperature correction of pH.) Something else is going on with the electrode proper. Its funny behavior suggests to me that it has dried out internally.
pH electrodes don't last forever. How old is this one? If it's an old one, it's probably time to replace it. If it's new and doesn't work, it may be under warranty.
If you shop for a new electrode, get a gel-filled one. And go for one with a silver/silver chloride reference instead of a mercury one -- especially if you are using it on food or other samples that may be consumed. Another consideration about calomel electrodes: they take hours to recover from relatively small temperature changes. Ag/AgCl references aren't as sluggish.
Finally, take care when storing the electrode. It should be stored under humid conditions to keep it from drying out. The best way is to put a small piece of cotton or glass wool soaked with distilled or deionized water inside the plastic end cap. For shorter-term storage, e.g., overnight, you could immerse the tip in pH 7 buffer.
I have a fisher stereo microscope on boom stand.
You need to tighten the coarse adjustment screws to provide more tension so it sticks. Leave the fine adjustment as it is, it works on a different system. It's the coarse adjustment crank that is slipping due to the weight of the stage and lack of pressure from the screws.
How do you change the bulb on a stereomaster
There are two ways to do it. There are 4 screws on the bottom plate that you can remove, but I find it easier to remove the frosted diffuser on the base plate. There is a thumb screw on the front that if you back it off a bit, the frost stage plate (diffuser) will pop out. Changing out the florescent bulbs can be a bit tricky this way, but if you angle it just right it will fit in and will save you a bunch of time.
The upper one is a bit easier depending on the age of it. They had two different styles. The newest on uses and MR11 style bulb, and to remove it all you need to do is to un-thread the metal housing that covers it. It just twists off. The older ones use a G4 style halogen bulb, and they are a bit trickier. I found it best to remove the two thumb screws on either side of the lamp housing (at the point where it piviots). Once removed the lamp house will drop down and you can get at the bulb.
AA-Spectrometer Unicam 939 Error
The error you are experiencing on your Unicam 939 AA-Spectrometer with the software reporting error 16 and 2, along with lamps 1,2,3,4, and 10 lighting up, could indicate a few different issues. Here are some steps you can take to try to fix the problem:
- Restart the spectrometer: Turn off the spectrometer and unplug it from the power source. Wait a few minutes, then plug it back in and turn it on again. Sometimes, a simple restart can fix issues with the instrument.
- Check the calibration: It is possible that the instrument needs to be calibrated. Follow the manufacturer's instructions for calibrating the spectrometer.
- Check the lamps: If multiple lamps are lighting up, it could be due to a problem with the lamp assembly. Check that the lamps are properly installed and functioning. Try replacing any lamps that appear damaged or worn.
- Check the power supply: Make sure the power supply is functioning properly by testing the voltage output with a multimeter. If the voltage output is incorrect, try replacing the power supply.
- Check the communication between the software and the spectrometer: Ensure that the software is properly communicating with the spectrometer. Check that the cables are properly connected and that the software settings are correct.
If these steps do not resolve the issue, it may be necessary to contact the manufacturer for additional support or to seek the assistance of a professional repair technician.
3/24/2023 6:39:35 AM •
Science &...
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Answered
on Mar 24, 2023
Eppendorf centrifuge model 5702: lid not does latch/lock after emergency release.
If the lid of your Eppendorf centrifuge model 5702 is not latching or locking closed after the emergency release, it is possible that the locking mechanism is damaged or misaligned. Here are some steps you can try to troubleshoot the issue:
- Check the alignment of the lid: Make sure that the lid is properly aligned with the base of the centrifuge. If it is not, the locking mechanism may not engage correctly. Adjust the lid as needed and try to latch it closed.
- Inspect the locking mechanism: Check the locking mechanism on both the lid and the base of the centrifuge for any signs of damage or wear. If you see any damage, you may need to replace the locking mechanism.
- Check the safety interlock switch: The safety interlock switch is a small button located on the base of the centrifuge that is depressed when the lid is closed. If this switch is not working correctly, it can prevent the lid from latching closed. Check that the switch is functioning properly by pressing it with a small tool while attempting to latch the lid.
- Contact Eppendorf customer support: If none of the above steps work, you may need to contact Eppendorf customer support for further assistance. They can help you troubleshoot the issue and provide advice on how to proceed.
3/15/2023 4:55:19 AM •
Science &...
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Answered
on Mar 15, 2023
Enigma 8 autoclave error code E13
The E13 error code on an Enigma 8 autoclave typically indicates a problem with the vacuum system. This error code is indicating that the vacuum is not reaching the proper level during the sterilization cycle.
Here are a few things you can check to fix the E13 error code:
- Check the vacuum pump: Make sure that the vacuum pump is functioning properly and that it is not blocked or clogged.
- Check the air filter: Make sure that the air filter is clean and not clogged. A clogged air filter can prevent the vacuum pump from functioning properly.
- Check the vacuum hose: Make sure that the vacuum hose is not damaged or disconnected.
- Check the door gasket: Make sure that the door gasket is not damaged or leaking. A damaged or leaking door gasket can prevent the vacuum from reaching the proper level.
- Check the control board: Make sure that the control board is not damaged or malfunctioning.
- Check the water level: Make sure that the water level is at the correct level in the autoclave chamber.
1/14/2023 10:21:30 PM •
Science &...
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Answered
on Jan 14, 2023
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