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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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30th Oct 2020, 2:06 pm | #1 |
Heptode
Join Date: May 2005
Location: Adelaide, South Australia
Posts: 541
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Fluke 87 multimeter overload
I'm rigging up a DC HT power supply and forgot I had been measuring mA with my Fluke 87 - touched the probes on the chassis and main filter cap (390V DC) and bang! - the display went blank for a few seconds and then came back on flashing and beeping - turned it off and then back on again but no function worked, volts measured low, display flashed and beeped would not settle on a range, my Fluke must be toast I thought - not a happy thought either.
Took me a few hours to get over the shock and to stop calling my self an idiot before I discovered the battery had gone flat almost at the same time I touched the probe on the capacitor, a new battery and it was all good, I was amazed it survived, the tip of the probe had been vaporized, I've damaged digital meters before with a much smaller overload. |
30th Oct 2020, 3:04 pm | #2 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Fluke 87 multimeter overload
The 87 is extremely well over engineered.
Saying that I ran my Brymen pocket DMM up to over 2kv until it made some unpleasant arcing noises and that still works fine! |
30th Oct 2020, 4:30 pm | #3 |
Nonode
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,015
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Re: Fluke 87 multimeter overload
You might need a new fuse for the mA input even if the Volts ranges work again.
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30th Oct 2020, 6:15 pm | #4 |
Heptode
Join Date: Mar 2014
Location: Meath, Ireland
Posts: 551
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Re: Fluke 87 multimeter overload
I did the same with my 83-iii a few years ago. The fuse saved the day and the cost of the replacement certainly makes me think twice now!
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31st Oct 2020, 12:21 am | #5 |
Heptode
Join Date: May 2005
Location: Adelaide, South Australia
Posts: 541
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Re: Fluke 87 multimeter overload
With my initial thoughts being that the meter was beyond repair I did checkout prices for used 87's - even older models like my series III are listed on Ebay from $200 and up, while I can afford it I'd find it hard to justify - there are just so many under $100 true RMS meters available now, I wonder if they would survive the same type of overload.
The fuse did blow I've ordered a new plus a spare - I wasn't expecting a $10ea price tag though. |
31st Oct 2020, 7:44 am | #6 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,670
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Re: Fluke 87 multimeter overload
I'm always doing similar things to my Fluke 25's, mainly HT whilst on the ohms range. The 25 has three big MOV's to soak up spikes, suppose the 87 has similar.
Andy.
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Curiosity hasn't killed this cat...so far. |
31st Oct 2020, 11:02 am | #7 |
Nonode
Join Date: Aug 2007
Location: South Bradford, West Yorkshire, UK.
Posts: 2,574
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Re: Fluke 87 multimeter overload
We had a Fluke 8020 for evaluation back in 1977 so we gave it a few tests to see if it was bullet proof. One test we tried was to measure the resistance of the mains! It passed and survived. I'm not going to deliberately try that with my 79 but it's good to know that Fluke have gone to a lot of trouble in the design to make it idiot, or engineer, proof.
Keith |
31st Oct 2020, 4:35 pm | #8 |
Nonode
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 2,820
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Re: Fluke 87 multimeter overload
I zapped my Fluke 23 with over 1KV from a TV line output stage once! It shut down, and I thought I’d knackered it, but touched the hold button and it sprang back into life, it’s still one of the best meters I’ve ever had, the only thing letting it down is the plastic case is cracked up near the display. I retired it when I got a Fluke 111.
Regards Lloyd |
31st Oct 2020, 4:44 pm | #9 |
Octode
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,604
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Re: Fluke 87 multimeter overload
Flukes are very well protected. They have proper safety category ratings too which can help protect the user also.
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Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW. |
31st Oct 2020, 7:17 pm | #10 |
Dekatron
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 4,311
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Re: Fluke 87 multimeter overload
I'm pleased to read this. After all these years I'm about to take delivery of my first Fluke - a second-hand 89 IV. I've yet to blow a cheap meter but it has to happen sooner or later. In the end the moving parts (4mm connectors and rotary switch) become unreliable and I think the cal has drifted on at least some of them (it has to have done - they disagree about the mains voltage !).
Cheers, GJ
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1st Nov 2020, 2:00 am | #11 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,998
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Re: Fluke 87 multimeter overload
There is a Fluke video taken by a visitor to their factory. They take a cheap Chinese meter, show that it reads 600V when 600V is applied. The then switch it to ohms and turn on the 600V - it goes up like an incendiary.
https://www.youtube.com/watch?v=OEoazQ1zuUM He then takes a Fluke 87 and connects 600V, and then turns the selector across all ranges back and forth. Absolutely nothing happens. No drama. Returns to DCV and 600V is read. I really would not buy anything other than Fluke - you know for sure it is not going to burst into flames in your hand! Craig |
1st Nov 2020, 10:27 am | #12 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Fluke 87 multimeter overload
I have been using a Fluke 11 for 30 or 40 years and have inadvertently tried to measure the resistance of the mains on a number of occasions, all that happens is that it shouts at you. I have never met anyone that has succeeded in destroying one
I bought mine after destroying several other digital meters, it was very expensive at the time but it has sure paid for itself. The LCD display is beginning to degrade now but it still works perfectly. Peter |
1st Nov 2020, 12:47 pm | #13 |
Guest
Posts: n/a
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Re: Fluke 87 multimeter overload
I got my Fluke (8020B I think) when I was an apprentice in 1981 (company issue), I was always amazed that it only went "beep beep..." when measuring the mains resistance as described above. Never did blow it up but lost it 30 years ago, it survived a 30 foot drop onto tarmac.
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1st Nov 2020, 2:47 pm | #14 |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,587
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Re: Fluke 87 multimeter overload
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1st Nov 2020, 4:23 pm | #15 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,643
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Re: Fluke 87 multimeter overload
When one of our riggers did the same with a 73 it didn't. I acquired it as scrap and found that the chip had unglued itself from the PCB. Some microsurgery restored it to health and I've used it for around 15 years since. Not even a crack in the case!
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1st Nov 2020, 6:20 pm | #16 |
Octode
Join Date: May 2016
Location: Oxfordshire/Bucks borders, UK.
Posts: 1,604
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Re: Fluke 87 multimeter overload
Luckily my Fluke 115 has survived a few drops, even from the height of the top of a full colour web offset press. Perhaps the day will come where it's had one too many drops, but I do try to not drop it.
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Avometer, vintage Fluke and Marconi collector. Also interested in vintage Yaesu and KW. |
1st Nov 2020, 8:16 pm | #17 |
Dekatron
Join Date: Jun 2016
Location: London, UK.
Posts: 3,687
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Re: Fluke 87 multimeter overload
I should have posted this video I did earlier. Fluke 25 is what you want for robust meter:
https://www.youtube.com/watch?v=eX4eme6c2S8 |
2nd Nov 2020, 1:12 am | #18 | |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Fluke 87 multimeter overload
Quote:
Peter |
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2nd Nov 2020, 6:12 am | #19 | |
Nonode
Join Date: May 2004
Location: Halifax, West Yorkshire, UK.
Posts: 2,587
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Re: Fluke 87 multimeter overload
Quote:
Alan |
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3rd Nov 2020, 1:29 am | #20 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
Posts: 3,601
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Re: Fluke 87 multimeter overload
They are a bit newer than mine Alan.
Peter |