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CAUTION : Remember that the High Voltage Circuit Cards operate up to 2000Vdc, and the HV capacitors can retain that charge for a considerable time. Any maintenance should be proceeded by removing the power cord from the AC or DC line. With the unit turned off let 5 minutes elapse until any disassembly occurs. This allows the Preamp's bleeder string to discharge the HV Circuit Card HV Supplies, and the associated capacitors, after which the HV circuit cards may be handled without fear of shock. No maintenance should be done with any input power (AC or DC) connected.
Rough Handling? Quick Fix In A Crisis
It has come to my attention that sometimes during shipping or from careless handling, Instruments can get "handled roughly", and possibly dropped hard. Accidents do happen! I am aware of only two such cases with my instruments, one was at the University of Connecticut, several years ago, when a unit was dropped during a UPS delivery, and recently another at the University of Miami. This last case left the AC power supply dangling by its wires. I have not yet received this instrument back for repairs, so I do not know what has failed. It is now out on the research ship Atlantis II, somewhere on the ocean doing Radon analysis.
It seems that with a little ingenuity there is almost always a fix. This time the AC power cord was disconnected and the 12Vdc power cord attached to the 12Vdc input. Power was then applied from an auxillary 12Vdc power supply. By using the DC capabilities of the DRC Instrumentation they were able to power the unit so that they could continue their research.
There are several things that can be done in this fashion in an emergency:
Check List:
1) If you suspect severe damage remove the electronics package from the case, by removing the 12 pan head machine screws holding the panel to the case.
2) Using the handle lift out the electronics package and inspect for damage.
3) If you find things loose or broken see if you can reattach them easily.
4) If not make sure that no wires are touching anything that could short out.
5) Wrap the loose items in cardboard or some form of insulation, and secure with black tape.
6) Check to see if all push-on connectors are securely attached.
7) The unit can then be powered by the included Yellow 12-24 Vdc power cord.
8) You may attach the power cord to another 12-24 Vdc power supply, or.
9) You may attach the 12-24 Vdc power cord to a 12 Vdc car battery.
10) If you use a 12 Vdc battery, also connect a battery charger to it.
11) It may help reduce noise to connect a large capacitor across the battery terminals. A 100mfd to 1000mfd at 50Vdc should be adequate. Adding this capacitor is not absolutely necessary but may help if you have a noisy battery.
If I have been made aware of other suggestions, I will post them here for anyone to see. If you have a suggestion that you think might help please, E-mail to Applied Techniques Co. here.
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