Discussion Category: UV/VIS Spectrophotometers
Yet another mouse issue
We recently acquired a used DU-640, and I've been tasked with getting it functional. It boots up and passes all its initial diagnostics, and at that point, the mouse pointer is in the top left corner of the screen. I'm able to move the pointer all around the screen with the keyboard keys, but I can't click on the option to get beyond the results screen. Is there a unique keyboard shortcut that can replicate clicking the mouse? Neither of the enter keys, the function keys, or control/alt keys seemed to do anything.
I've been reading through the threads and I'm confident in my ability to modify the mouse's serial port with the jumper between pins. What I'm wondering is if there is a way to tell if I have a motherboard revision that includes the fix. Thanks.
The sad thing is that it really doesn't take much to place an in line bar display to show how much time the lamp has actually been on. In fact, Beckman's HPLC UV lamps had that installed like forever but we couldn't get the spectro division to do the same instead relying upon the timer built into the spec itself. The only problem was that if you had to replace the main board, which happened way too often, you also lost the lamp on time and only the DU800 kept track of the Visible lamp on time.
The key thing to look for is how discolored is the area around the opening of the anode inside the lamp. A new lamp should be clean and a used lamp will have some dark discoloration around that opening. A really old lamp will have a lot of discoloration.
Anyway, after replacing the lamp, turn both lamps on for 30 minutes or so and then "slightly" loosen the four screws on the lamp housing and adjust the housing position to maximize the output voltage at the test point on the main board at 240nm. Tighten the four screws and then check your visible lamps position for maximum voltage at 500nm because if you had to move the housing for the UV you will most likely have to adjust the visible lamps position.
OK, thanks Don. The only way I would consider aligning and potting it would be if it was a huge price difference. Do you know anyone who sells these? Recommendations? I look forward to the software copy. Thanks Don
Chad J. Stoltzmann
The bulb came in a box with the second 640 I bought. In retrospect, I really only have their word it's a "new" bulb, but it's definitely less discolored than the bulb I replaced.
Chad, If they are shipped in the lamp housing then they are "probably" prealigned. There is no way, however, to empirically tell whether they are new or used. Best thing to do is ask but all Beckman lamps starting with the DU60 series were prealigned in the housing. A non prealigned requires you position the lamp manually and play with the position until the beam is properly positioned and the energy is maximized. Then the lamp has to be potted inplace with heat resistant potting material. I certainly wouldn't waste my time doing this and I know how it is to be done.
Hope your doing better. So how do I know they are pre-aligned or ask for them from the vendor? Sorry if you posted this earlier. But can you explain the difference. Does Beckman even still sell these?
I'll email you my address too.
Chad J. Stoltzmann
Chad, just make sure that any lamp you buy is PREALIGNED. Otherwise, you will have to do it yourself andvwhile it may seem simple, you usually only get one shot at doing it correctly. That's why all field replacements were sent to the engineers prealigned.
P.s. please resend your mailing address for the WinConnect software.
Chad J. Stoltzmann
Milder, glad to be of assistance on your spec. Just remember, the visible lamp procedure does not take into account a lot of the possible variation in the lamps. There is a high probability that you can get even more energy from the lamp, it just takes a little more work.
You are correct about everything related to the peltier cell holder. I hope posting signs works but I have seen signs be ignored in the past. Your training them personally should have the desired effect. If it doesn't, pop the cover off of the controller and it will be obvious which fuses have blown.
I got a bit swamped with some other issues, but I finally got back to this. I've replaced the visible lamp since I wasn't getting 1V at the detector. I did use an official Beckman bulb, and the alignment outlined in the manual worked perfectly. The UV bulb has over 1000 hours on it, but we'll be replacing that in the near future. By the time the students come back to school and classes are using the spec, we should have a new bulb in it.
The peltier unit we bought was used, and the thermal paste was flaking off all over the place. I did take it apart and clean it up, and it's working beautifully. I've put a sign on the unit insisting that no one unplugs the peltier unit. I'd like to just leave that one installed. There doesn't seem to be any downside to having it there even when the temperature control isn't needed. I'm the one who will be training faculty and students to use the instrument, so I'll stress that they shouldn't need to touch the connector.
Thank you for all your help, Don and Chad. I'm excited to have this instrument up and running, and several of the faculty are really looking forward to the kinetics experiments they can use in their classes. Thanks again!
The light path failure is typically caused by a blocked beam such as by the cell holder. Since you have ruled that out, it will probably be the visible lamp. The only lamp that is used at start up is the visible at 500nm where the minimum voltage needs to be 1.00volts measured at the gold vertical test point in the left front corner of the main board near where the cable from the detector plugs into the main board.
Replacing the lamp is not difficult and the basic alignment is fairly easy. Unfortunately, the basic alignment doesn't always get it done. Please do not try to use an over the counter lamp. Commercially available visible lamps have a coating on them that prevent UV light from getting out of the lamp whereas the Beckman Coulter bulb does not and that can have a profound effect on the amount of energy getting to the detector assembly. If you look at the visible lamp and it is anyway blackened at all then it is time to replace it. You stressed wanting to take readings at 260nm and 280nm's. What does the UV lamp hours register? Anything over 1000 hours will make the lamp suspect although it will probably still perform OK as every lamp is quite unique in its performance. Get back to me if you need anymore help.