Author Topic: Fluke 8920a Voltmeter Repair Need Help  (Read 781 times)

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Offline daisizhouTopic starter

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Fluke 8920a Voltmeter Repair Need Help
« on: May 28, 2023, 10:35:38 pm »
Hello everyone,My fluke8920a voltmeter has been under repair,It's malfunctioning very strangely,I tested it for a long time,it's still faulty now.

Below I will describe its failure phenomenon,After power on,Press the "LO RANGE ENABLE" button,The analog pointer keeps swinging back and forth,I don't know what's broken.
I try to plug in a 50 ohm load,And press the "LO RANGE ENABLE" button again,The malfunction is still the same.
In order to explain the fault more clearly, I took a video,Please let me know if you know or you have the same glitch, thanks

https://youtu.be/l_2e7JcHB2g

repair manual-->https://www.elso.sk/media/download/pdf/fluke/man/Fluke_8920A_8921A_Manual.pdf
« Last Edit: May 28, 2023, 10:39:59 pm by daisizhou »
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Offline daisizhouTopic starter

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Re: Fluke 8920a Voltmeter Repair Need Help
« Reply #1 on: May 29, 2023, 03:05:25 am »
S202 switch
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Online coromonadalix

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Re: Fluke 8920a Voltmeter Repair Need Help
« Reply #2 on: May 29, 2023, 02:32:35 pm »
check the logic going into U205, it may have been damaged ???
 

Offline daisizhouTopic starter

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Re: Fluke 8920a Voltmeter Repair Need Help
« Reply #3 on: May 29, 2023, 08:22:03 pm »
thank you for your reply。I checked U205 it is working,Sometimes press "LO RANGE ENABLE" it is normal, sometimes it is faulty
I wiped the motherboard with ethanol and baked it, the fault disappeared for a while, but the fault reappeared after a while
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