Author Topic: fluke 87  (Read 2499 times)

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Offline jtwrangler

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fluke 87
« on: July 27, 2012, 11:47:12 pm »
I am new to forum. I purchased a used fluke 87 from ebay which was supposed to be in working cond. when turned on without leads in it clicks or beeps through all selections except ua and ma.with leads setup for v and ohms it beeps through all selections except ma. also when set up leads for a it beeps as should but when setup for ma it beeps on every setting. when selecting ohms it beeps louder and faster and displays OL. Any help would be greatly appreciated to try and do a diagnostic on this meter.

I had taken a 10 week course in electronics 35 years ago and decided that I wanted to try relearning again as I had become disabled , but want to keep my mind busy.

Thanks in advance for any help

Regards Joe
 

Offline JuiceKing

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Re: fluke 87
« Reply #1 on: July 28, 2012, 12:58:09 am »
I am new to forum. I purchased a used fluke 87 from ebay which was supposed to be in working cond. when turned on without leads in it clicks or beeps through all selections except ua and ma.with leads setup for v and ohms it beeps through all selections except ma. also when set up leads for a it beeps as should but when setup for ma it beeps on every setting. when selecting ohms it beeps louder and faster and displays OL. Any help would be greatly appreciated to try and do a diagnostic on this meter.

I had taken a 10 week course in electronics 35 years ago and decided that I wanted to try relearning again as I had become disabled , but want to keep my mind busy.

Thanks in advance for any help

Regards Joe

Doesn't sound right. The beeping is intended to warn you that your leads are shunted, so don't use them in any setting except for measuring current, in series.

If you have the leads in the COM and A jacks, it should beep at every setting except mA/A. If you move the red plug to the mA/uA jack, it should beep at all settings except mA/A and uA. With the leads in the COM and V/Ohm/diode jacks it doesn't beep at any setting.

Have you tried a fresh battery? Maybe this is what can happen with a weak one.
 

Offline jtwrangler

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Re: fluke 87
« Reply #2 on: July 28, 2012, 02:17:59 am »
I put in a fresh battery and also checked the fuses
 

Offline ProBang

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Re: fluke 87
« Reply #3 on: July 28, 2012, 04:04:01 am »

Hello.

The Fluke-87 uses an optical system to prove, which socket (perhaps: The wrong!) is connected to a lead.
If some dirt is (or something sticks) in the "mA"- Socket, then it starts the alert in the other functions.
Maybe the meter is "repaired", if you clean the socket, i.e. with some pressured air.

Greets and good Luck
If you think my english is bad...
- then should you read my french!
 

Offline djerickson

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  • Country: us
Re: fluke 87
« Reply #4 on: October 12, 2016, 03:28:40 pm »
Same here. My older 89-IV started beeping in all ranges except current. Re-soldering the current jacks helped, but after a month it got worse, constantly beeping. I solder-wicked the old solder on the current jacks, re-soldered with basic rosin flux solder, and cleaned with flux remover. Now it works perfectly. But I was curious what the root cause for the problem was.
I couldn't find an 89 schematic, but I found an 85-87 schematic and assume the circuit is similar.  On the 87, the lead sense circuit for the 10A jack uses a 10Meg pull-up resistor. The one for mA uses a 30M pull-up resistor. These are giant values and any board contamination could be seen as a logic 0, an installed lead. My meter had a previous battery leakage problem. That probably caused the board leakage, but dirt, oil, age, water, lack of board cleaning can also cause it.
Hope this helps.
Dave Erickson
 

Offline MosherIV

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Re: fluke 87
« Reply #5 on: October 12, 2016, 03:46:02 pm »
Hi

It could be the input jacks are broken. See MrModemHead web page on re-building the input jack.

http://mrmodemhead.com/blog/fluke-80-series-jack-assembly-rebuild/

(only a possibility - not saying this is the definitive cause )
 


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