Fluke 25 fixed

[kernowcam]

I am well pleased with my efforts today. I fixed my Fluke 25 with no fuss today.

I was doing some amps testing using the meter today and current flow was 100mA no problems. Things ground to a halt and I realised the meter was no longer passing current. assumed a fuse blown.

Checked fuses, all OK. Stripped meter and did some obvious checks and eventually found the small fuse holder clips had gone slack.

Then discovered my stash of Fluke 25 spares from when I bought 25 from a surplus shop. Still quite a few bits around.

[Sinewave]

Lovely meters these are. For some reason I have quite a few of them. Just my collecting habits I guess.

[kernowcam]

I refurbished quite a few, sold the scrappers but kept a few boards, displays, cases etc. just In case!

I think I have 4 good ones. A bit excessive. But yes, lovely meters.

[evingar]

Another vote for the 25 here.
I have one as my main meter. I also have a new old stock one in pristine condition waiting for the day I kill it. Despite much physical and electrical abuse over more than a decade, it still soldiers on though

[MrBungle]

Plus if someone breaks into your house you can use it for self defence!

I keep meaning to pick one of them up to see what all the fuss is about. They certainly look extremely well made. Definitely less flimsy than my 87.

[Andrewausfa]

They are very robust, I bought two for wider stereo seperation when measuring voltages. The only thing is the screen can get a bit dim which is fixable.

[ajgriff]

As the Fluke 25 was originally designed for use in mines it's hardly surprising that it is robust and proved to be just as useful in battlefield environments. However, if you are used to an AVO 8 it is small, light, easily portable and can be dropped from quite a height or even dunked in a bucket of water without functional consequence. Add to this its protection circuitry & safety features and it is difficult to criticise the overall concept.

The low second hand value is another bonus as far as I'm concerned. I paid £8 for my ex-MoD example relatively recently. It was described as 'spares or repair only' but cleaning the LCD contacts brought it back to full health.

You should definitely try one Mr B.

Alan

[MrBungle]

That's not a bad price for a decent DMM. I'll probably pick one up if I see one go past.

The aforementioned Fluke 87 I have was actually picked up a few weeks back with the same display contact issue you mention. Seems to be endemic. Unfortunately the jack assembly was knackered as well on that and it got very expensive very quickly!

[ajgriff]

Originally Posted by Andrewausfa

The only thing is the screen can get a bit dim which is fixable.

I'd be interested know how this is achieved. My Fluke 25's display is not as clear as other Flukes in my armoury as illustrated by the attached photographs. In both instances the outer screens have been polished and the LCD contacts have been cleaned. I'm aware that the upper polarising filter can dim the display and I've seen it suggested that exposure to heat or strong sunlight can cause degradation of the LCD crystals themselves. When I polished the screens I had the impression that the 25's was slightly tinted whereas the 75's was perfectly clear. Any thoughts appreciated as I'm reluctant to mess around with the 25 as it's my favourite DMM despite the display lacking a little contrast.

Alan

[Andrewausfa]

Hi Alan,

Restorable I may have better said, in that's all I did take the screen apart and clean the contacts which brought the digits back to life. If I recall, and it was a few years ago, some of the segments of were quite dark, some not so, so if you had, say, '20' indicated you might have two different shades of grey in the segments of each numeral. I also seem to recall, one of the digits would barely work until I cleaned the strip...hmmm maybe another meter.

Both of my '25's displays are about the same as yours to be fair and I do agree the screens look tinted. And my '75' is much clearer too.

I'd like to get my hands on the 27 FM US service version, which is more featured and comes in a much bigger box with a HV probe.

Andrew

[McMurdo]

My daily meter also after my Beckmann started with intermittent switch problems . Also bought the Fluke for very little really, my segments are a little low contrast and there's no 'auto off' so sometimes I arrive on Monday morning to find it still switched on! The switch contacts occasionally need cleaning on Ohms. Deadly accurate with no adjustment ever needed during my ownership.

[Diabolical Artificer]

Another fan of 25's, I have two as my main meters. I also had the loose fuse contacts on one of mine. I love the fact they have no auto turn off, this ain't a problem as they run for ages on the PP3.

The manuals for these are available online both the operators and service with schematics, the operators is well worth a read as these meters do stuff that isn't obvious at first.

My only minor winge is that the lowest current range uses a 630mA fuse which isn't a common value and haven't any of so often use a 1A with impunaty.

Andy.

[Sinewave]

I managed to get those 630ma fuses from CPC.

[ajgriff]

My thanks to Andrew for his feedback regarding the display. It's interesting that he also thinks that Fluke 25s have a tinted screen.

I got some 630mA HRC fuses from an eBay seller Andy. I'll see if I can find a spare and, if so, will pop one in the post.

One of the main challenges with my ex-MoD 25 was removing the paint, permanent marker scrawl and label residues from the protective shell case. Took much longer than fixing the missing segment LCD issue. However, having cleaned the case I found the blank recesses had a sort of 'something should be there' look so I made some labels as shown in the attached photo. Completely unnecessary of course!

Alan

[Andrewausfa]

Alan,

I'm not sure the Fluke 25 was designed expressly for mine use, it came out of the earlier Fluke 8025A, made to US military contract which I imagine was pretty rigid in itself. The 8025B evolving into the '27' and then sideways to the US military 27 FM which has an extra chip for the True RMS function.

Yes, the cases are a mess! Someone here at work suggested writing over the permanent marker with a dry wipe/whiteboard marker would get it off. That was after I'd spent ages scrubbing. That method does actually work, certainly on recent applications of permanent marker on my desk.

Andrew

[MrBungle]

On the subject of cleaning, does anyone know how to get rid of dirt on the yellow holsters? I can't seem to find anything that works. It just gets worse!

On repairs, my 87 looked like this when it turned up, illustrating the holster gunk:



After cleaning, replacing the jack assembly (TME sell them), cleaning the zebra strips for the display, it matches my current in cal 87V perfectly. 25 years between these two meters. This is why I like Fluke stuff!

[ajgriff]

Appreciate your thoughts on the design history Andrew. In any event it's testimony to the design that it was still in production in Fluke 27 form until relatively recently.

Thanks for the tip about dry marker pens. Will remember that next time I encounter unwanted permanent marker graffiti.

If I happen to come across a 27 FM US Service Version in a cardboard box under a trestle table I'll let you know!

Alan

[ajgriff]

Originally Posted by MrBungle

On the subject of cleaning, does anyone know how to get rid of dirt on the yellow holsters? I can't seem to find anything that works. It just gets worse!

Try soaking overnight in a solution of soda crystals followed by a good scrub.

Alan

[MrBungle]

Thanks for that - will try that tonight!

[Diabolical Artificer]

"I'm not sure the Fluke 25 was designed expressly for mine use" Pretty sure they were, see attached, though this refers to the 27 in this case I'm certain I've read the same of the 25.

"I got some 630mA HRC fuses from an eBay seller Andy. I'll see if I can find a spare and, if so, will pop one in the post." Thanks.

I have some pliers and cutters that have a very similar yellow plastic handle's, I use meth's to clean them.

Andy.