EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: firewalker on July 02, 2018, 03:57:51 pm

Title: Fluke 87 III Over Load indication.
Post by: firewalker on July 02, 2018, 03:57:51 pm

Some time my Fluke 87 III displays an Over-Load on volts scale without anything connected. A simple tap on the rotary switch is enough to fix it. Bad contacts?

(https://i.imgur.com/75qS354s.jpg) (https://i.imgur.com/75qS354.jpg)  (https://i.imgur.com/8T0nYVks.jpg) (https://i.imgur.com/8T0nYVk.jpg)

Alexander.

Title: Re: Fluke 87 III Over Load indication.
Post by: Fungus on July 02, 2018, 09:00:14 pm

Certainly sounds like it.

Pull it apart and rub them with spit, that usually does the trick.

Title: Re: Fluke 87 III Over Load indication.
Post by: retiredcaps on July 02, 2018, 09:57:57 pm

See

http://mrmodemhead.com/blog/fluke-83-iii-rotary-switch/ (http://mrmodemhead.com/blog/fluke-83-iii-rotary-switch/)

"It basically works and seems to be calibrated correctly, but occasionally when set to measure Ohms, the display will flicker a bit and only display “OL”, regardless of whether the leads are connected to anything, or even shorted together.  A slight tap on the rotary switch will cause it to start working correctly again.  Odds are, there’s a minor problem with the internal switch contacts."

Title: Re: Fluke 87 III Over Load indication.
Post by: mzacharias on July 04, 2018, 12:56:48 pm

DeOxit D-100L. Apply directly to switch contacts. Do not use a spray cleaner.

Title: Re: Fluke 87 III Over Load indication.
Post by: Fungus on July 04, 2018, 01:45:24 pm

I refer you to time 12m02s in this video:

https://www.youtube.com/watch?v=u2-ot2vWLxI (https://www.youtube.com/watch?v=u2-ot2vWLxI)