Radiometer D53

The Optima series ultracentrifuge series actually has two temperature sensors built into it. One is found attached to the underside of the cover that goes around the spindle and over the radiometer assembly. It is responsible for reading the chamber temperature above 100u. As soon as the vacuum transitiins below 100u the radiometer takes over so you are in fact NOT seeing a temperature readout from the radiometer at all. Your problem could be the radiometer or it could be with the electronics responsible for switching from the thermistor over to the radiometer but not much I can do to help you beyond that from where I sit. I can try digging out my manual to see if there is anything you can do for further troubleshooting but when I was in the field I would simply try a new radiometer instead of chasing down electrons. If I come up with anything that you can use I will repost to your post.

Don

Don:

Thank you. Yes, there are two temp monitors.  I think you might have misunderstood. The temperature reads correctly from the 'can' thermocouple under the center plate (above 100u), but readings go astray and variable following the switch to the radiometer at less 100u vacuum. It's clear that the readings are from the radiometer in that sense, but we're unsure that the problem is the radiometer proper or the circuit that receives the radiometer's data. We're thinking we have to try switch out the radiometer and see what happens.  Any help would be awesome!  Do you have a pdf service manual and or schematic? 

Best!

Sorry but my service manual is a paper copy but I suspect your radiometer is the souce of the problem. Is the black metal flake in the center of the radiometer floating free and facing up other than the two wires connecting it to the rest of the radiometer? Is the shiny aluminum foil at the bottom of the radiometer still in place? I have to ask those questiins in order to help. The Optima radiometers did have some issues from time to time and at one pount we had a recall and replace on them so you may just have one of those units. I'll check the manual later today and get back to you.

Don

Thanks Don for your time.

We looked aht the radiometer with a mangnifier the and the black wafer and wires look intact.

An ohmeter accross the plates suggests that the wires to the junction on the wafer are making good contact.

BTW: We may be able to acquire an XL-80 parts unit that has a blue front and interface panel with squarer buttons compared to our XL-100K which has a cream coloured front panel and more rounded buttons. Do you know if these two units would have the same radiometer?

Other than eproms, would boards also be interchangeable?

Thanks. again!

I forgot to mention, the flake is floating. We also cleaned under it. In our radiometer, the area under the wafer doesn't appear to be a foil(?), but appears to be a more solid aluminium base.

Thanks!

First, the difference in outside covers was purely cosmetic and provided that the circuit boards are of the same revision they would absolutely be interchangeable assuming that the boards themselves are still functional. I believe that you will find that the boards on the chassis will be the same so they should not be an issue In some cases the EEPROMs could be swapped out directly from one control board to another but there were some firmware revisions that also required a newer revision board in order to work properly. If I was going to be swapping anything around it would be by swapping out both the control and display ccontrol boards as a set unless by some chance they are of the same version of firmware on both boards. Not sure if I still have a copy of the matrix print out of what would work together and if I do I will copy it and post it for you. Having said all of this, the radiometer is absolutely interchangeable so swap away.

Don