1) Turn off all power to the unit and unplug the mains cord. (If the unit was on wait 5 minutes. 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.)

2) Remove the 4 nylon nuts from the blue plexiglas panel and remove the panel.

3) Using the board puller, remove the boards one at a time and mark them with an identifying mark. Wipe their contact fingers off with a good contact cleaner. (any TV or Radio Shack supply store should carry this) Check the printed circuit cards for any growth of oxidation on the solder side of the card, spray with contact cleaner and brush with a stiff brush. (Cut off the bristles of a regular small 12mm wide natural bristle paint brush, leaving about 15mm of brush length) The least you should do is to remove any dust that you find.

4) Carefully remove the IC's with help of an IC puller or a very small screw driver. Using the good or new eraser end, of a # 2 pencil, gently rub the contacts to remove any oxidation on the IC pins, do both sides sides of the contacts. Shape the eraser with a razor blade if necessary, so that it fits in between the IC pins. If the unit is generally not stored or treated properly, remove the chips from the sockets and gently use this method every few years. Spray the sockets with contact cleaner and then re-insert the chips in the sockets making sure that the number one pin mates with the number one socket hole. There are several different configurations of socket layouts and I have shown several for you to look for to find pin#1. Pin #1 will be marked in some fashion on both the sockets and the IC chips. Press all of the integrated circuit chips firmly into their sockets to make sure that none loosened in transit. The above procedure can be handled by any good electronics technician and it should be an easy job for him to remove, clean and replace the IC chips.

5) The only other connectors that might need checking are inside the case. To check these you have to remove the 12 pan head stainless steel screws that hold the front panel onto the case. Using the center chrome handle lift out the entire electronics package and carefully place the electronic package on its side, making sure that there is proper support. Remove each of the Pre-amp twist lock connectors one at a time (counter clockwise to remove / clockwise to install) and inspect and clean if necessary with contact cleaner. (it is impossible to mix up these connectors because they are different by design, and if you look at each it will be obvious which they are) While you have the electronics package out you might check any push on connectors that you see for looseness, that might have loosened by vibration in shipping. Also be sure to mark the Pre-amps with #1 and #2 so that you can change their positions if necessary. Re-assemble the electronics package into the case (do not replace the 12 stainless steel screws at this time, wait until you are finished testing).

6) Now your ready for Troubleshooting real problems. This means replacing systems boards one at a time and keeping track of results. Also which Counter/Timer cards and HV supply cards are in which slot, and with which Pre-amp, and with which Tube/Chamber. If you are careful you can eliminate most problems quickly. Just do one change at a time, the first being to switch the Tube/Chambers and reset the HV supplies to the (switched chamber) settings. The second is to switch the HV Supplies (Remember to change their settings to correspond to the Tube/Chamber requirements). Next switch the Counter/Timers, and then switch the Pre-amps.(You may be able to just switch the Pre-amp connectors if there is enough cable length)

7) Please be advised that under these conditions of alpha counting the working life of the Photomultiplier tubes are approximately 4 years, and the life is shortened by exposing them to light even when they are off. The reason for this is the gradual poisoning of the Photo-cathode. You should always use the Lite-Tite cloth Hoods when changing samples and you should check to see if you are letting light in when you change samples. This can be done simply by starting the counter and watching spurious counts come in when you remove the chamber cover and insert the cell and then replace the chamber cover. If you notice many spurious counts coming in you might try to solve this by improved technique. You may also turn off the HV supply or just turn off the mains, when changing samples. The HV supply will return to exactly the same voltage when it is turned on again. You do not have to change the dial setting, it can remain locked on the plateau voltage setting