Solving problems caused by electrolytics has never been easier, now that you can locate these bad capacitors easily without having to unsolder them, and without spending time troubleshooting, by using the CapAnalyzer 88A Series II.
As a cap ages, it can cause problems in the particular circuit it is in. In a TV vertical section, it can cause underscan or overscan problems. In audio or mpx circuits it can cause distortion or low audio. In the syscon supply it can cause intermittent functions and mpu confusion. In the video circuits it can cause a fully scrambled picture. In VCR or camcorder servo circuits, it can cause unstable speeds. Most VCRs and big screens also use surface mounted electrolytics in the sound MPX decoder module and video PIP and convergence circuits. High-end audio, video and computer products use tantalum capacitors that can become leaky by as much as 500 ohms. Computer motherboards are another user of electrolytics that must have super-low ESR, or else strange problems and freezing can occur.
Measuring a cap in circuit is more difficult than measuring a resistor, because circuit resistance and capacitance can affect readings. Some "capacitor checkers" claim to work in circuit, but they give such erroneous readings you have to unsolder and re-measure each cap out of circuit anyway. Some of the most expensive LCR meters will not measure capacitors accurately in circuit. Some meters measure the capacitance at two different frequencies, and show it as two different readings!
The trick to locating bad capacitors in circuit is not just to measure capacity, but instead, to measure Equivalent Series Resistance (ESR) and DC Resistance (DCR) in relation to capacitance. A perfect capacitor will measure as an open circuit at DC, and will show less AC resistance as the frequency across it increases. Most cheap cap meters utilize this fact by measuring a cap's impedance at a fixed frequency such as 1 KHz and translating the reading to capacity. In reality, checking a cap at 1KHz is pointless because in TVs, computer monitors, and PWM power supplies, frequencies of 100 KHz and higher are used. The CapAnalyzer 88 was the first device that would measure both DCR and ESR automatically.
The currently available CapAnalyzer 88A Series II adds improvements such as DCR range to 500 ohms for testing smd tantalum caps, and additional features such as a battery-saving quick ESR test mode InstaESR that bypasses the DCR test for the quickest ESR-only test, and updated LED display drivers that increase accuracy and decrease battery drain.
Other ESR meters have their limitations; they don't check DCR for leaky or shorted caps and you must discharge each cap before testing, or risk damage to the meter. Their test probes add their own capacitance, and readings vary depending on the position that the probes are held. Also, these meters usually don't use a frequency high enough to isolate the specific capacitor to be tested.
The CapAnalyzer 88A uses a test frequency higher than any other DCR/ESR meter (over 100KHz), automatically discharges the cap under test, checks DCR first (up to 500 ohms), then checks and displays ESR on a 20 segment LED bar scale, and beeps from one to five beeps depending on the ESR condition of the cap. Both DCR and ESR measurements are made at levels that isolate the cap under test from the rest of the circuitry. Because it checks DCR first with its exclusive "DCR Set Alert", it will alert the technician immediately if the cap or anything else in that circuit is shorted or leaky, before it checks ESR. Range covers just about any electrolytic or tantalum capacitor you will come across, from 0.47uF to 2200uF.
Be aware that there are look-alike meters like the B+K Precision 881 that hope to lure you into buying what you think is our CapAnalyzer 88A. The B+K won't check tantalums in-circuit, and because of its limited DCR range of only 30 ohms you will never be 100% assured that you've found every leaky capacitor. The omission of the DCR set alert and many other qualities that have made our made in USA CapAnalyzer 88A the choice of over 20,000 technicians throught the world, should make your choice obvious. In fact, our CapAnalyzer 88A is the number one asked-for-by-name cap checker in the world; see the short list of major users (above left) that buy the CapAnalyzer 88A in large quantities for their technicians. Why? Because only the EDS-88A CapAnalyzer advertises 100% accuracy, and 20,000+ technicians have proven this as fact.
CapAnalyzer 88A includes a low-capacitance one-handed tweezer test probe for accuracy and ease-of-use. Because it is dual-microprocessor controlled, it has more features and is much more accurate than other cap testers. A three-color chart on the front panel shows typical ESR readings of good and bad caps in relation to their capacitance. Portability and battery operation make it ideal for repairs on site, eliminating a double service call and valuable technical travel time. An AC adapter is availiable for continuous use on your bench.
So make your job easier, and get your own CapAnalyzer 88A. No other test equipment on your bench will make you a hero for so little money. No wonder that the CapAnalyzer 88A is the most widely used and asked-for-by-name capacitor tester in the world.
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