Hey y'all. I know this is a long-shot. But I'm pretty desperate at this point so I figured I'd tap the EEVBlog to see if anyone can help.
I am an in-house engineer maintaining the lab equipment for biotech company. In >90% of the ~400 pieces I am responsible for, the manufacturers will not provide service manuals, schematics, etc. Very limited resources for the customer to repair the instrument themselves. This is a topic in itself. But it is the most challenging part of my job.
I am trying to repair a Molecular Devices SpectraMax ABS Plus. It is a spectrophotometer (called a microplate reader) for measuring absorbance of 96-well/384-well plates for biological/chemical samples. The unit has developed a 401 error - which according to the manual states 'the filter wheel is unable to find its photo interrupt'. Usually, when the manufacturer uses the term 'photo interrupt' they are referring to an optical homing sensor. However, the filter wheel in this unit has no optic homing sensor. The predecessors to this unit (such as SpectraMax M2) did have homing sensors for their filter wheels. This is just an example of how bad this company's manuals are - they just kept the old error code descriptions. In fact, the only note they provide in the maintenance section of this manual (besides the error codes) is how to replace the fuses!!!!
Anyway, I found out that this error usually means the optics are misaligned. I can see that aligning the optics is accomplished by making adjustments to set screws on the diffraction grating (or monochromator). But the problem is, I have no way to control the Xenon flash lamp manually. It only comes on while running an experiment or during the unit's initial start-up calibration/initialization. I need to be able to control the lamp to keep the beam on as long as need while I make adjustments to the diffraction grating.
Usually lab equipment like this has two operational modes 1) normal use mode 2) service mode. The service mode is usually kept hidden. It is either a different application entirely (buried in the program files folders if you're lucky) or it is enabled by some keystrokes within the regular software app. I was unable to find any service mode for this unit. I was however able to open a 'chat window' by pressing CRTL+SHIFT+ALT. In this window, I can type 'error' for example and get a list of all error codes triggered by the instrument over its lifetime. I tried typing things like 'lamp on' to see if I could turn the lamp on, but no success. I was even able to externally control the lamp with my power supply and pulse generator, but this doesn't seem practical either.
I apologize for the lengthy post, but I am hoping someone on here might know a procedure for the optical alignment of these instruments. As I said, it is definitely a long shot. It would probably have to be someone who worked for Molecular Devices or has lengthy experience repairing these model microplate readers. I don't have high hopes, but I figured I would at least try.
Thanks in advance!
-Frank