fluke 87 - Page 1
Forum section: electronics / beginners

author: jtwrangler
author_rank: Newbie
timestamp: July 27, 2012, 11:47:12 pm
content: 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 helpRegards Joe

author: JuiceKing
author_rank: Regular Contributor
timestamp: July 28, 2012, 12:58:09 am
content: Quote from: jtwrangler on July 27, 2012, 11:47:12 pmDoesn'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.

author: jtwrangler
author_rank: Newbie
timestamp: July 28, 2012, 02:17:59 am
content: I put in a fresh battery and also checked the fuses

author: ProBang
author_rank: Contributor
timestamp: July 28, 2012, 04:04:01 am
content: 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

author: djerickson
author_rank: Regular Contributor
timestamp: October 12, 2016, 03:28:40 pm
content: 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

author: MosherIV
author_rank: Super Contributor
timestamp: October 12, 2016, 03:46:02 pm
content: HiIt 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 )