Appeal from the Circuit Court of Cook County.Honorable Lawrence Edward Flood, Judge Presiding.
 The opinion of the court was delivered by: Justice South
 This appeal arises from defendant's conviction following a jury trial for driving with a blood-alcohol concentration (BAC) of .08 or more and driving while under the influence of alcohol. He was placed on a period of 18 months' court supervision with the condition that he undergo three drug tests during that period and pay a fine of $325.
 At trial, Officer Richard Barber of the Chicago police department testified that on July 22, 1999, he was on routine patrol when he observed defendant's car in front of him. At that time, the car crossed over the divided white line several times, and the brakes kept going on for no apparent reason. Based upon these observations, Officer Barber effectuated a traffic stop. As he was speaking to the driver, defendant, he observed that his eyes were bloodshot, his speech was slurred, and he stuttered. He also detected a strong odor of an alcoholic beverage on his breath. Officer Barber then ordered defendant to get out of the car and noticed that defendant's balance was unsure, and he was swaying from side to side.
 Defendant agreed to take two field sobriety tests at the request of Officer Barber. The first test was the one-leg stand. He was instructed to stand on one foot and lift the other foot six inches off the ground for 30 seconds. Officer Barber testified that defendant failed this test because he was unable to keep his leg raised for 30 seconds, and he put his foot down twice within 20 seconds. Defendant was then administered the horizontal gaze nystagmus test (HGN). Officer Barber testified that as a police officer he had been trained and certified to administer the HGN test and had performed it hundreds of times over the past 10 years. He described nystagmus to the jury as an involuntary jerking of the eyeball while it is moving slowly from one side to the other. The subject is instructed to stare at an object or stimulus and follow it with his eyes without turning his head. In this case, Officer Barber chose a pen as a stimulus and held it 12 to 15 inches from the tip of defendant's nose. Defendant was instructed to stare at the tip of this pen while Officer Barber moved it from left to right. It was explained to the jury that if the eye jerks within a 45-degree angle, that is a sign the person is impaired. In this case, defendant's eyes jerked within a 45-degree angle, causing Officer Barber to conclude that he was under the influence of alcohol. Defendant was also asked to perform two other field sobriety tests, i.e., the walk-and-turn and finger-to-nose tests, but he declined. At that time, he was placed under arrest and transported to the police station. At the police station, after defendant was read his Miranda rights, he admitted that he had consumed six beers prior to driving that evening. He also agreed to take a Breathalyzer test, the results of which showed that his blood-alcohol concentration was .10.
 On appeal defendant has raised four issues: (1) whether the trial court erred in excluding evidence of the Breathalyzer machine's malfunctions; (2) whether the trial court erred in admitting the HGN test absent a Frye hearing; (3) whether the trial court erred when it prevented defendant from cross-examining the police officer about his overtime compensation for appearing and testifying in court; and (4) whether the trial court erred in imposing fines without making a prior determination as to defendant's ability to pay.
 Prior to trial, defendant filed a motion in limine to exclude the results of the Breathalyzer test. In that motion, he argued that the State would be unable to lay a proper foundation for the admission of the Breathalyzer because (1) the inspector had failed to perform a second analysis on a certified controlled reference sample the month following defendant's test at an interval not exceeding 45 days from the first certification, and (2) the State would be unable to demonstrate that the reason for the machine's removal from service two weeks after defendant's test was unrelated to and did not concern the accuracy of his test. In support of this motion, defendant sought to call Larry Etzkorn, the technical administrator for the Alcohol and Substance Testing Program of the Illinois State Police. The State objected to his testifying, so the trial court conducted a voir dire outside the presence of the jury.
 During that voir dire, Etzkorn testified that in 1999 he was the district chief for the Alcohol and Substance Testing Program with the Illinois Department of Public Health. As the district chief, he was responsible for overseeing the monthly accuracy certification of Breathalyzer test machines used in the State of Illinois. He was also a certified Breathalyzer operator and a Breathalyzer instructor. One of his duties as the district chief for the Alcohol and Substance Testing Program was to maintain the records that came off of the certifications and to monitor the information. In conjunction with those duties, logbooks were maintained at the site with the instrument with respect to the chemical tests that were performed on them. One of the things reflected in these log books was the certification process.
 In May of 1999, Etzkorn received a malfunction report regarding the Intoximeter 3000, serial number 0438, which is the machine defendant was to be tested on two months later. A malfunction report is a report that is sent in by an inspector whenever an instrument is malfunctioning. On May 20, 1999, it was reported that there was a malfunction of the " T-Cell" on machine number 4038. The T-Cell is a secondary sensory device which is part of the machine's analytical components that picks up on any interference which may cause a machine to produce a false positive. That interference could be, for example, acetone from a diabetic or anything else in the air. According to Etzkorn, problems with T-Cells are rather common and can occur every two to five years. If there is a problem with the T-Cell, that information is conveyed by the instrument itself. In other words, the instrument reports the particular type of malfunction and will not permit itself to operate until the problem is repaired. The particular message that was displayed in this instance was that the T-Cell was "out of range." Etzkorn testified that when that occurs, the machine will not permit a sample to be taken.
 According to the logbook for this particular Breathalyzer, the T-Cell was replaced, and the machine was recertified and placed back into service. On July 7, 1999, the entry in the logbook for machine number 4038 states that the T-Cell was no longer a problem, and it was certified as accurate, which means it was acting appropriately and providing results within the allowable range for that instrument. According to Etzkorn, if the T-Cell were still malfunctioning, the machine never would have completed the certification process.
 On August 5, 1999, two weeks after defendant's test, Etzkorn testified that he received another malfunction of machine number 4038. This time the report stated that the "flow thermistor" was not operating properly and, therefore, was unable to obtain a sample. He described the flow thermistor as a sensor valve that regulates the temperature. This valve remains open while the subject is blowing into the machine. Once the subject stops blowing, the flow thermistor closes, and a sample is taken.
 Etzkorn described the flow thermistor as a very important component of the instrument because it gives a proper deep-lung sample. On August 5, 1999, the flow thermistor was closing too soon, thereby preventing it from taking a full sample. The August 5, 1999, report stated that the cause of this problem was unknown other than normal "wear and tear."
 According to Etzkorn, the flow thermistor was replaced, but the machine continued to give unstable and erratic readings. Ultimately, the determination was made that the machine was not functioning properly enough to be placed back into service, so it was not certified and eventually destroyed.
 Etzkorn testified that in his expert opinion the machine on which defendant was tested on July 22, 1999, was working properly. In support of that opinion, he emphasized that if there had been a problem with the flow thermistor on July 22, 1999, the machine would not have produced a reading. He described all Breathalyzer machines as being self-diagnostic, and that if they detect a malfunction, they will not proceed any further or provide a chemical test result. Etzkorn also stated that the ticket from machine number 0438 indicates that it did, in fact, run a self-diagnostic check for internal problems on July 22, 1999, and that the test indicated that the instrument was working properly at that time. He did not confine his testimony to the T-Cell or the flow thermistor. He stated unequivocally that if there had been anything wrong with the instrument, it would have reported the problem and refused to take a sample.
 At the conclusion of the voir dire, the trial court held that Etzkorn would not be allowed to testify because his testimony was irrelevant since the only issue before the jury was whether the Breathalyzer was functioning properly on July 22, 1999, when the test was administered to defendant. The court made repeated references to Etzkorn's testimony that if the machine had been malfunctioning on that date and time of defendant's test, it would not have produced a reading or sample. The court concluded that the problem with the machine on August 5, 1999, did ...