Electronic Design Specialists | Maker of the CapAnalyzer 88

Technical support

Click on the symptom:

Calibration Instructions
Intermittent testing, ESR shows too high or not at all
5 Beeps and no ESR reading at all with old EDS-88 or 88A
Lost my Owner's Manual
After a Nasty Discharge, strange behavior
Batteries only last a few hours in original EDS-88 or 88A
Update my EDS-88 to EDS-88A
Broken Tweezer test probe
Button gets pushed on in toolcase
Low Battery indicator doesn't work with original 1998 EDS-88
No detection of Shorted caps with original 1998 EDS-88
Readings keep changing each time the same cap is checked
Sometimes the 20 ohm led comes on dim with another led
Power button seems to have a delay powering up
(2011 or 2012) DCR test doesn't work, ignores shorted caps

Field Calibration Instructions:
Although full accuracy is best done with 1% resistors with the values shown on the 3-color chart, as we do in the factory, these field calibration instructions will be very close.

1: Set the ZERO and FULL trimmers fully to the left (counter-clockwise). Set the SET ALERT slider to zero (all the way down). Have a 20 ohm resistor handy.
2: Turn on the unit; it will chirp three times and immediately go into the ESR alignment mode and wait; one of the led bar segments will be on. Hold the tweezer probes across the 20 ohm resistor and adjust the FULL trimmer so the the bottom 20.0 ohm just comes on.
3: Quickly, before the CapAnalyzer resets, short the probe tips together and adjust the ZERO trimmer so that the 0.10 led bar just goes out, and only the top OHMS bar led is on. If you did not move the probe quickly enough, simply tap the probe tips together again briefly to start the test, and wait until the CapAnalyzer is in the ESR test again (after the green OK led comes on) before quickly shorting out the probe tips again.
4: Touch across the 20 ohm resistor again and make sure the 20.0 ohm ESR bar still comes on. You might have to touch up both trimmers.

1: Set the FULL trimmer fully to the left (counter-clockwise) and the ZERO trimmer in the center. Have a 20 ohm resistor handy.
2: Turn on the unit; it will double-chirp and automatically go into the QuickESR test mode and wait. Hold the tweezer probes across the 20 ohm resistor and adjust the FULL trimmer so that the 20.0 led bar just comes on.
3: Short the probe tips together and adjust the ZERO trimmer so that the top led bar just dims slightly.
4: Touch across the 20 ohm resistor and make sure the 20.0 ohm ESR bar still comes on.

You can double-check the ESR scale by measuring various resistors between zero and 20 ohms and make sure the ESR readings agree with the resistors. Just make sure you are in the InstaESR mode or CapAnalyzer will complain about Low DCR since capacitors aren't supposed to have DC readings!
Lost your owner's manual? press here to download a copy.
If your unit seems to be intermittent in checking caps, there can be three causes. Turn on your CapAnalyzer in the InstaESR mode and squeeze the probe tips together and see if the top 0.10 ohm LED comes on. Check each possible cause in this order:

  • Make sure the probe tips are clean. Sliding a piece of paper between squeezed probe tips usually works.
  • Poor solder connections of the wires of the Pomona tweezer probe or the cable to the probe body could be the problems. On the original (1997) EDS-88 with straight tweezer handles, the problem is usually at the probe tips. Remove a quarter of an inch of insulation of the wire where soldered to the brass tip, then run a bead of solder from the tip to the wire. On early (1998) EDS-88A series one units with Pomona-branded curved probe tip ends, the problem has been oxidized crimps where the coaxial cable connects to the red and black wires in the apex of the tweezer. The probe handles must be snapped apart, easily done with the help of a flat-blade screwdriver. Solder the brass crimps and snap the probe handles together using a small amount of super glue. This problem no longer exists with Series II CapAnalyzers with probes made after 2002 and those labeled with the EDS name as we now make them properly in-house. Normal wear and tear causes the coax bending to cause breakage of the cable where it enters the tweezer; this is verified by wiggling the cable at the tweezer body while doing the "squeeze test" in InstaESR mode. Snap the tweezer apart, shorten the coax an inch, resolder, reassemble and superglue the tweezer.
    If you would rather replace the tweezer, the entire probe/cable assembly is available for $29; go to the Shop page.
  • On some units, the relay could have bad contacts. While doing the squeeze test, tap the CapAnalyzer on the bench while looking at the ESR LEDs. After each bang, the LEDs should return to the 0.10 ohm LED. If after each bang a different LED remains lit, the relay must be replaced. Use only the Omron G5V-1, available at Digi-Key, part# Z773.
  • Some users have reported that the 1998 and 1999 CapAnalyzer 88A does not check bi-polar electros (like the ones in Thomson TV chassis), by beeping 5 times and showing no ESR reading. Actually, the reading is less than zero! One of our users with a Sencore LC101 reported that the Sencore actually showed minus ohms. Strange cap (play Twilight Zone music here). Just remember that five beeps and no reading of ESR leds means a good BIPOLAR cap; however, if this happens on a regular electrolytic, you might check the section above. By the way, this is only noticable on CapAnalyzer 88A units made before August 2000; since the original CapAnalyzer 88 units had an "ESR" led above the lowest reading that always remained lit, it fooled most technicians in reading it as a lower value. CapAnalyzer 88A series II (all units made after July 2000) have a different LED driver chip that correctly lights up the top LED. BANG!
    Although your CapAnalyzer will discharge a cap before testing it, sometimes a cap is just a little to big and charged up a little too high for the CapAnalyzer to handle. The auto-discharge is mainly to make readings more accurate and is not designed to discharge large, primary HV electrolytics right after the bridge. Short these with a screwdriver. If you ignore this warning, after a large discharge, you will know that you have damaged your unit if it keeps going into test mode as soon as you turn it on, or seems to try to test a cap and shows DCR LOW on every cap. The fix is usually easy and cheap; see the drawing. Simply replace the three resistors shown; they are designed to protect all of the active electronics. Use 1 watt metal oxide for the 4.7 ohm and 3 watt wire-wound for the 0.47 or 0.6 ohm discharge resistor. If your unit keeps going into test mode as soon as you turn it on, check the two discharge diodes (out of circuit) by the 3W resistor. If it seems normal at first, yet shows DCR LOW on every cap, replace the LM324 chip.
    An important note here is that stupidity can still destroy a CapAnalyzer. Forget to remove power from the TV or VCR that you want to check the caps in, and your CapAnalyzer will happily kill both the unit-under-test as well as itself. Besides replacing the three resistors, you'll also have two 220 ohm resistors next to the large 1000uF/10VDC cap that will be burnt up, and you'll also need to replace the NE555, TLC2272, and the LM324 chips. DO NOT SUBSTITUTE USING NTE, ECG OR ANY OTHER SUBS! Beware that the board is double-sided and through-plated and you need to use desoldering equipment designed to work with this type of board. Soldering braid won't work. If you do not have the proper equipment, you may send your unit and we will repair and calibrate it for you. See the "Repairs" webpage for details. And next time, let's be more careful out there!
    The original EDS-88 and EDS-88A units are rough on batteries. Most techs report between 3 weeks and two months, as long as the unit is turned on just long enough to check some caps, then turned off. Some of the bigger shops would prefer to keep it on all the time. Don't try to make your own adapter; any voltage higher than 6.25V destroys the mpu. We can send you an upgrade kit that includes the DC jack and specially modified adapter; see the Order Form page. We can modify your CapAnalyzer for you as well. Or order a brand-new CapAnalyzer 88A Series II with the optional adapter option already installed and give your old CapAnalyzer to the field tech. (The series II units get double the battery life because of upgraded LED driver chips). To order a new unit, or parts for your old unit, go to the Shop page.
    A feature many users of the original CapAnalyzer had asked for is the quick ESR test mode that bypasses the long discharge and DCR test when you are sure that no shorts exists, such as checking all of the surface mount caps in a camcorder or video module as quickly as possible. The EDS-88A made after 1998 has this feature.

    Available is a replacement mpu chip for the original 1997 EDS-88. With this new mpu, turning on the CapAnalyzer with the test probe tips touching tells the C88 to enter the new program...now as soon as you check a cap, the ESR test is done immediately, in a split second. To use the original full discharge and DCR test sequence, simply turn on the C88 normally. This mod is available if you send your unit back to us; see the "Repairs" webpage. We will also update your unit to current specs, so if you have the original C88 without the three-minute warning timer, you will get this also. There are no updates for the analog measuring circuitry, because after all, you can't improve upon perfection.

    As you know, the original 1997 CapAnalyzer 88 automatically checks capacitors for low DCR (DC resistance) before checking ESR. The original 1997 EDS-88 has a range adjustable from zero to 50 ohms. However, if you are troubleshooting boards that use surface mount TANTALUM capacitors (not electrolytic), we have discovered that in rare cases, these capacitors can become leaky with DC resistances as high as 500 ohms. Therefore, a new range of up to 500 ohms DCR is the solution. The EDS-88A has this new range; on the original 1997 EDS-88, there is a simple and easy fix: Open your unit and locate the 27 ohm resistor just above the "ZERO" trimpot, and replace it with a 270 ohm resistor. Now, mentally add a zero to the 0 to 50 ohm DCR ALERT adjustment. However, BE AWARE that if you measure normal electrolytics, you must set the slider to the "5" (now 50 ohms). Use the higher range for small tantalums or electrolytics under 47 uFd. You will get a false "LOW DCR" if you try to measure a large electrolytic with the slider set too high, because the time to charge and test the cap is longer than the DCR test check. TEST LEADS
    The original tweezer probes from the original CapAnalyzer were poorly made by Pomona. However, since 2010 we now make EDS Tweezer probes in-house using our much improved design. They are also designed to be repaired, not replaced. Intermittent readings are almost always a broken coax shield at the tweezer; simply snap the tweezer apart with a flat blade screwdriver and you can redo the connections. Reassemble using super glue. If the berillium copper tips are broken off they can be replaced individually and are available for $6/pair. The entire probe/cable assembly is available for $29; available direct from EDS. Give us a call or email. Singing the "RED BUTTON BLUES"
    A couple of complaints from the outside guys fixing the big screens about the power button being accidentally pushed on in transit. The quick fix is to simply pull the red button off of the switch--you won't break anything, and you can push it back at any time. A somewhat in-elegant solution, (sorry) but very functional, you can easily push the power on or off with your small finger. NO LOW BATTERY INDICATOR and NO DETECTION OF SHORTED CAPS
    If your older C88 seems to work poorly with low batteries and the "low battery" led does not seem to work properly, you may have one of a small batch of 20 CapAnalyzer 88 units made on 4/18/98 that had out-of-spec MPU chips. These units work fine with fresh batteries. If the unit fails to warn you on a shorted capacitor when the batteries are weak, return your unit directly to EDS for a replacement mpu chip and current updates. If you seem to keep getting different readings when testing the same capacitor, especially on larger caps, tap the CapAnalyzer gently on the workbench while the ESR of a good 1000uF cap is being displayed. If the ESR reading changes (flickering is ok), you have a bad relay. Replace the relay only with the Omron G5V-1, available at Digi-Key, part# Z773.. If the bottom 20 ohm led sometimes comes on dim with another, brighter led above, this is a normal circuit glitch with all C88A units made before August 2000 (caused by our interfacing the National LM3914 led driver ICs into the CapAnalyzers mpu for the improved multi-tone beeper). The brighter led above is the correct reading. Again, the series II units after August 2000 have a new driver chipset that eliminates this glitch. If you notice that your new C88A seems to delay powerup, Series II C88As use a pair of MCUs that check calibrations and communicate with each other for about a second before flashing the LEDs and beeping OK. This is normal, so stop playing with the red button! A batch of CapAnalyzers made in 2011 used a 2SC1775 for Q1 instead of the usual 2SC945, since Panasonic no longer makes the C945. These appear to be Chinese knockoffs and fail. The symptoms are that the DCR test no longer works since the relay doesn't click over. We advise to check your unit by shorting the tweezer and making sure the "LOW DCR" LED illuminates. If not, replace Q1 with an original 2SC945 or any general purpose NPN transistor with the same ECB pinout. Since the Japanese no longer make transistors, we will be designing future products with American 2N3904, but if you use this remember that the pinout is different.


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