B. Did the scan motor find the home position? (If mechanically jammed it will squeal.) If the
coarse and fine sensors don't find home (4000) the M500 will have to drive 360 degrees at the 3
minute speed to retry. (To save time turn the 500 on and off for a faster reset.)
C. Has the display cable become partially disconnected? (Turn off, re-plug and turn M500 back
on.)
2. No energy reading.
A. Is the source on? Yes – (Glows orange go to C&D).
B. No – Source Out: Is there 2.8 volts D.C. across the 16 gauge yellow and blue wires on the
terminal strip? (If yes, turn off and replace the source assembly. Power up the 500 and align
the source image on the entrance baffle for maximum energy on the display after warmup). No
voltage present contact BUCK Scientific, Inc.
C. Is the filter assembly stuck in the wrong position? (Clean the filter carriage rods of any films
with an alcohol or acetone dampened paper towel). If F2 is in F1 position at 4000 it will let no
energy through the system. If it still sticks, polish the rods with a +600 grit sand paper. Make
sure the spring is still correctly attached.
D. Detector failure? With the 500 initialized for at least a few minutes, move your fingers rapidly
in and out of the light path behind the exit slits. (If good, the 500 will give some type of
change on the display). If nothing, contact Buck Scientific Inc.
3. A large WIDE doublet at 2350 wavenumbers (Can be positive or negative with changing
amplitudes).
A. This is atmospheric CO
2
. The 500 will quantitatively show the difference in CO
2
concentration
in the air between the reference and the sample runs. This is much more dramatic if the 500 hasn't
warmed up enough and the CO
2
concentration goes up due to more people in the room. This is the
only thing happening here so don't let it bother you, an F.T.I.R. will show the same thing. A
double beam system will not show this unless the balance is off but the CO
2
is still absorbing
almost all the energy.
4. Noisy spectrum in the 3800 area and the 1900 to 1200 wavenumber area are produced by
atmospheric water bands. Their non-cancellation is due to insufficient warm up time. Do not close
the sample door when running, leave it open. (Close it at the end of the day to keep the dust out).
Temperature changes inside the 500 can make minute <1 cm
-1
changes which look like noise due to
improper cancellation of data points. The fans help stabilize the 500 after warm up.
5. No spectrum after X-wavenumber or no spectrum at all.
A. Wrong cell/window material was used with the sample.
EXAMPLE: Quartz after 2000 or salt after 670. Solution change the material.
B. Bad sample preparation (EX. KBr disk has water in it or too thick).
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