Products > Test Equipment
Fluke 189 with leaking surface mount supercap (also Fluke 287, Fluke 289)
Jay_Diddy_B:
Hi,
I can report two DIY fixes of Fluke 289s.
Unit 1
Symptoms: unit works fine, all reading correct, kills the batteries in a few days, even if switched off.
Findings:
Measured current consumption around 30 mA when off. Removed the CAP C145, off current dropped to 45uA
Connected C145 to power supply, set 3.3V with mA meter in series. Test confirmed bad supercap.
Fix: Replaced the super capacitor with Panasonic Coin Super Capacitor 0.33F 5.5V EEC-S0HD334H
(This is larger than the original but it can be made to fit)
Unit 2
Symptoms: unit works fine, all reading correct, loses time and data if batteries are removed for about 10 minutes
Findings:
Measured current consumption around 2 mA when off. Removed the CAP C145, off current dropped to 45uA
Connected C145 to power supply, set 3.3V with mA meter in series. Test confirmed bad supercap.
Fix: Replaced the super capacitor with Panasonic Coin Super Capacitor 0.33F 5.5V EEC-S0HD334H
(This is larger than the original but it can be made to fit)
I think that Panasonic was optimistic in rating the original part at 3.3V. Typical values are 2.7V for a single capacitor and 5.5V for the parts that internally have two capacitors in series.
Unit 3
This is a unit that I purchased new and has very few hours of use. The current consumption of this meter was 45uA when off.
Regards,
Jay_Diddy_B
casinada:
Good job Jay.
Why didn't you send them to Fluke? At least they do a Calibration verification after the repair. :)
BravoV:
--- Quote from: Jay_Diddy_B on May 13, 2014, 03:52:18 am ---... current consumption around 30 mA when off.
--- End quote ---
Wow .. 30mA !!!! :o
Those darn cap are sucking the batteries power so bad even the meter is turned off, I guess they will be sucked dried in days.
Btw, did you measure the capacitance of those goo oozing bad caps ? How much left ?
JDB, thanks for reporting this. :-+
xwarp:
--- Quote from: Jay_Diddy_B on May 13, 2014, 03:52:18 am ---Fix: Replaced the super capacitor with Panasonic Coin Super Capacitor 0.33F 5.5V EEC-S0HD334H
(This is larger than the original but it can be made to fit)
--- End quote ---
What had to be done for the new cap to be made to fit?
If this cap is nothing more than being used to keep the time in memory for the time it takes to replace batteries, then can a lower voltage be used if the size is closer to the original?
WVL_KsZeN:
Never use a lower voltage, only a lower capacity. Actually, you want to use a cap with a higher voltage to make it last longer.
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