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Old 14th Jan 2017, 12:26 am   #41
Craig Sawyers
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Default Re: Which Digital Multimeter?

Quote:
Originally Posted by ionburn View Post
Not sure if it has been mentioned in the various replies but one thing to note is that if you are using old service literature for servicing then the voltage reading etc will likely be given as read by (typically) a 20kOhm / Volt meter (eg AVO 8) so using a digital meter will usually give different readings. These may differ radically from the service literature. Ok if you realise this but it is still useful to have the equipment from the day. Although I use a digital meter most of the time I would not be without my analogue equipment which will sometimes give a far clearer indication of what is happening
All quite correct. I also have three AVO 8 of various vintage for 20k-ohm/volt applications. Plus a couple of Fluke differential voltmeters, which are null reading and essentially infinite input resistance (actually of order 10^14 ohms) at null.
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Old 14th Jan 2017, 12:42 am   #42
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Default Re: Which Digital Multimeter?

When digital meters first appeared on the market I bought a couple of what was available at the time and managed to blow them both up - and they weren't cheap. Someone recommended a Fluke to me but they were very expensive, I bit the bullet and bought one and still have it, a Fluke 8 I think it was, it seems indestructible, if you try and measure the resistance of the mains with it, it just shouts at you but continues working, it was also the first meter I had with auto shutdown so you didn't have to replace battery every week. The only problem with it now is that the display is disintegrating at the edges but at the moment its still perfectly usable.

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Old 14th Jan 2017, 6:25 am   #43
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Default Re: Which Digital Multimeter?

You don't need a fancy meter as said previously. One thing the more expensive meter's have is better protection, very handy if you forget to switch to DC volt's and then test HT whilst on the ohms range.

Everyone has their own preference, I'd recommend an old Fluke 25 23 27 or 73 cheap and pretty indestructable.

Andy.
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Old 14th Jan 2017, 9:59 am   #44
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Default Re: Which Digital Multimeter?

Totally agree that Budget permitting it is certainly preferable to have two identical (or similar) units.

1. One remains in use should the other ever go off site for recalibration/accuracy test
2. DMM failure modes, when they do happen, aren't always obvious.
3. Like clocks- Two can tell you the time, One can tell you what the time probably is.
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Old 14th Jan 2017, 10:58 am   #45
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Default Re: Which Digital Multimeter?

Ah - but if one DMM is off, how do you know which of the two is right? So you need 3 DMMs, right?

And before you know it: http://s185.photobucket.com/user/exc...age-2.jpg.html

(not my photo, just to be clear )
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Old 14th Jan 2017, 11:35 am   #46
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Default Re: Which Digital Multimeter?

One thing that rarely gets mentioned about Flukes, is the 'fading display segment' problem, which as well as countless internet references has occasionally cropped up on the forum:

https://www.vintage-radio.net/forum/...d.php?t=100156

I could afford to buy a new Fluke, but I don't need one and don't want one and I certainly wouldn't buy one in preference to a new budget one such as the Toolzone. As a hobbyist, a Fluke wouldn't confer any benefits to me that something like the Toolzone or any other budget meter doesn't provide, in terms of the functionality provided, or safety of the meter or the test leads (which have shielded plugs). I'm too young to die and too old for nasty shocks, but I think the 'shroud waving' comments about the safety issues are misplaced.

As to accuracy, I have a precision 10V standard, and of perhaps twenty meters, both digital and analogue that I have around the house, workshop, garage and in the car, (including Maplin 'two for a fiver' ones) which I've checked, they're all more or less spot on. Apart from that, I'm not sure why hobbyists need an accuracy to ten decimal places, which in my event can only be assured on any meter by frequent recalibration. I'd much prefer a new budget meter to a secondhand Fluke of dubious provenance.

On vintage radios, a few volts here and there is rarely of concern, and where a digital meter is being used, will in any event read higher then a 20k Ohm per Volt AVO 8 analogue meter originally used when the radio maker's service data was compiled.

Hopefully, by now, the OP - a novice restorer - will have made his mind up which way he wants to go. It used to be said that 'no-one got the sack for buying IBM computers' I guess the same could be said for Fluke if 'FUD' rules the day. (Fear, Uncertainty and Doubt)!
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Old 14th Jan 2017, 11:35 am   #47
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Default Re: Which Digital Multimeter?

The other thing that high quality branded DMM's have is excellent protection for both the meter and the human.

At the front line is the correct High Rupture Capacity fuses, which are non-trivial, specialised, surprisingly large, and expensive. There are also clamp diodes and fusible resistors as additional lines of protection. As an example in Fluke DMMs there are two fuses - with rupture ratings of 10,000A and 17,000A, which is the current that they can interrupt without arc flashover in the fuse, or exploding.

Chinese DMM's generally just have a regular 20mm glass fuse and nothing else, which offers very little protection. Sure it will blow in a mild overload, but in a heavy overload, or abuse, it can (read: will) flash over between the end caps and just keep on conducting through the arc set up via the metal vapour left by the fuse wire, or explode.
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Old 14th Jan 2017, 12:23 pm   #48
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Default Re: Which Digital Multimeter?

I've had the fading segment display problem on my Fluke 79 several times. It appears to be down to poor contact between the display, the conductive rubber block and the PCB. It's a fairly simple matter to strip it down and clean the LCD contacts, conductive block and PCB contacts with I.P.A then re-assemble it (taking less time than James May would take in his re-assembler series!).

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Old 14th Jan 2017, 12:26 pm   #49
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Default Re: Which Digital Multimeter?

I currently use a DMM bought s/h for a fiver at the NVCF two years ago. I've mentioned it on the forum in the past, and find it adequate for most things, although I miss the autoranging feature on my Fluke 77. As Craig says, my DMM, like many, only has a 20mm glass fuse, and I doubt that it would be possible, due to lack of space, to replace it with the type of fuse fitted in Fluke meters. I also have a Russian Analogue multimeter, which gets little use, but is handy at times.
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Old 14th Jan 2017, 12:46 pm   #50
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Default Re: Which Digital Multimeter?

Quote:
Originally Posted by KeithsTV View Post
I've had the fading segment display problem on my Fluke 79 several times. It appears to be down to poor contact between the display, the conductive rubber block and the PCB. It's a fairly simple matter to strip it down and clean the LCD contacts, conductive block and PCB contacts with I.P.A then re-assemble it (taking less time than James May would take in his re-assembler series!).

Keith
I have that in my very oldest 8060A. I've had it to bits several times and cleaned the contacts and the surfaces of the rubber contact strip. Well, it kind of works for a while, and then some segments become dim again. This thread might just have encouraged me to have another go.

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Old 14th Jan 2017, 2:23 pm   #51
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Default Re: Which Digital Multimeter?

It's worth saying that Fluke are not the only people to have had issues with LCD panels made back in the '70s and '80s. I don't think I've heard of problems in designs newer than that. Away from the glass itself, the elastomeric connector might need a clean occasionally, but that again is not confined to Fluke. More recent models use gold plated pads on the PCB to solve this.

I'm pragmatic, and could agree that 1 or 2 (or 3 ) "cheap but good" meters might be all that most vintage radio hobbyists need.

But I will just say that experienced engineers feel duty-bound to point out the problems with the cheap multimeters so that people can make informed purchasing decisions and use them wisely. It's not because we're "fanboys" - it's because we care
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Old 14th Jan 2017, 3:31 pm   #52
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Default Re: Which Digital Multimeter?

I suspect that if you buy cost effective meters from RS, Farnell or Rapid you latch onto their signed certificate of conformity, and their duty of care not to sell inherently dangerous products.

A good example of this would be http://uk.farnell.com/beha-amprobe/a...git/dp/2396478 which is certified to CAT III 600V (with suitable probes, that is), which means that it is suitable for measuring voltages inside a consumer unit, and anything downstream of that. It is £27 plus VAT. Max DC/AC volts is of course 600V.

If you need more volts this one is CAT III 600V/CAT II 1000V http://uk.farnell.com/beha-amprobe/a...eld/dp/2082815 and has a DC range (for measuring inside valved gear, CAT II) of 1000V. It is £68 plus VAT.

There are also ones by the same manufacturer that are CAT III 1000V/CAT IV 600V but they are more expensive at £110 - £126 plus VAT

General specs of the range here http://www.farnell.com/datasheets/15...019.1480838933

I would definitely wear goggles and lightweight gardening gloves if I was poking around a consumer unit, BTW.

Personally I would be confident in buying any of those - and might well do in the not too distant just to add to my DMM capability.
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Old 14th Jan 2017, 3:54 pm   #53
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Default Re: Which Digital Multimeter?

Quote:
Originally Posted by 'LIVEWIRE?' View Post
As Craig says, my DMM, like many, only has a 20mm glass fuse, and I doubt that it would be possible, due to lack of space, to replace it with the type of fuse fitted in Fluke meters.
You could gain some extra peace of mind by replacing the glass 20mm fuse by a ceramic bodied one with a higher rupture capacity rating.

There won't be room for a proper 11/2 x 13/32 inch HRC job, though.

Maybe an inline "bulge in the lead" mod could be used.
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Old 14th Jan 2017, 4:24 pm   #54
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Default Re: Which Digital Multimeter?

Quote:
Originally Posted by David G4EBT View Post
Hopefully, by now, the OP - a novice restorer - will have made his mind up which way he wants to go.
Thanks David - your quote above made my day!

A "novice" indeed - haven't been so flattered in a long time.

As for making my mind up, I'm beginning to think I should never have asked the question as people on here are really passionate about such things. There also seems to be an undercurrent that implies that as I am a "a novice restorer" I don't need, shouldn't have or don't qualify for an upgrade to my basic Duratool meter?? (Not you David).
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Old 14th Jan 2017, 5:13 pm   #55
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Smile Re: Which Digital Multimeter?

OK - I've been on the soapbox so long on this thread, I'd pretty much forgotten the original question

OK the Fluke 115 originally suggested is a fine meter, is has CAT III 600V approval, and has safety approvals from UL, VDE and TUV. If 600V AC/DC max is OK for you. It is also true RMS. It is a really fine and bullet-proof meter from the Rolls Royce manufacturer. And it will cost you £200; if that fits your budget - buy it, no hesitation.

The BEHA-AMPROBE series from Farnell that I linked to are much more cost effective; the AM-500 (linked to earlier) at £33 inc VAT is CAT III 600V and does pretty much everything that the Fluke does, but not true RMS if that is important to you. They are also silent on fuse and protection, and international approvals (although it is CE marked). I have no idea if it will be as bulletproof as the Fluke.

The only iron clad advice I'd offer is stay away from eBay for DMMs.
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Old 14th Jan 2017, 5:34 pm   #56
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Default Re: Which Digital Multimeter?

I don't know what the spec of your Duratool meter is Donald, but in terms of your stipulated requirements in your first post, I suggested that the Toolzone one would do all that you require except measure frequency. It will perform all the other functions you mention including test caps and transistors. Based on my experience and others I know, it will do so reliably and safely. I wouldn't personally use a multimeter for frequency measurement, and in any event, find little use in vintage radio restoration for my frequency counter.

I was trying to make the point - but perhaps not very well - that for the price of a Fluke which - from my perspective confers no advantages for a hobbyist over a good quality well specified budget meter such as Toolzone one - that you could also buy a signal injector/tracer (Velleman K7000 or whatever) - probably the most useful item you could have next on the list to a multimeter for speedily pinpointing faults in a non working radio, and could also buy a Chinese 'multi-tester'. Which will test transistors inc FETs, resistors, caps, inductors etc and still have change in your pocket.

If by some hopefully unlikely mishap Anyone did wreck a budget meter, that's £15.00 down the gurgler. No dramas.

But of course, if you can afford a Fluke and that's what takes your fancy, as I hope I've implied, then by all means - it's your choice and you've more than enough feedback from the Fluke fan-base to make an informed choice! The reason I chipped into the thread is that whenever anyone seeks advice about test gear, invariably, some forums members will say that for meters there's only one show in town - Fluke. For scopes it must be Tek, and if you want a soldering iron, it must be a Weller Soldering station, and so forth.

As I said earlier, this sort of thread tends to generate more heat than light.

I guess I'm biased in the other direction - as a hobbyist, I enjoy electronics construction as well as vintage radio restoration, and most of my test gear is home built, though I've pensioned off the PW Purbeck Scope I built in 1980 and replaced it with a Hameg 203-7. I've still got the signal injector I made as a teenager in the mid 1950s, which used two (very expensive at the time) OC44 transistors.

Every good wish in your restoration endeavours Donald, whatever you decide to buy. As you will have noted in your restoration thread, you'll get all the advice, help and encouragement on here that you need to see each restoration through to a successful conclusion.
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Old 14th Jan 2017, 5:41 pm   #57
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Default Re: Which Digital Multimeter?

Quote:
Originally Posted by Craig Sawyers View Post
The only iron clad advice I'd offer is stay away from eBay for DMMs.
Oy, both my Fluke 25's came from ebay

I would edit that:-

"stay away from ebay unless you are buying something good/ recognisable and you are confident you can tell if a 2nd hand (good/ recognisable) meter has been aversely "adjusted" by a previous owner".

It's all become a bit verbose though
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Old 14th Jan 2017, 5:45 pm   #58
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Default Re: Which Digital Multimeter?

Stayed out of this one until now...Right tools for the job...Simples.

Good luck whicheverways.

Lawrence.
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Old 14th Jan 2017, 8:29 pm   #59
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Default Re: Which Digital Multimeter?

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Originally Posted by David G4EBT View Post
invariably, some forums members will say that for meters there's only one show in town - Fluke. For scopes it must be Tek, and if you want a soldering iron, it must be a Weller Soldering station, and so forth.
These things entered folklore so long ago that they have a profound effect on prices. If you do know of alternatives off the beaten track which are still good, then your pocket takes less of a battering.

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Old 14th Jan 2017, 9:00 pm   #60
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Default Re: Which Digital Multimeter?

Hi

As has been said before, there are plenty of good meters out there. You can pick up a secondhand digital meter made by Beckman which are quite good meters at a reasonable price.
As member ionburn points out be careful interpreting voltage readings on vintage equipment where voltages on the circuit diagram were often quoted using an Avo 8 with 20kOhm/Volt sensitivity. I also own many analogue meters and use my Avo 8 Mk3 when needed. Horses for courses.

My first encounter with Fluke meters was in the mid 1980's at an electronics firm that I worked for and I wasn't originally a Fluke fan until I started owning one and realised it lives up to it's name as far as quality and dependability goes. As I said, I paid £170 for it in 1987, bought 2 sets of leads/probes at £20 a time. Total money spent over 30 years is £210, that works out at £7 a year! Maybe I've been lucky with the service I've had from my meter. It still looks as new, the rotary switch feels right with no wear, the case is also excellent and has worn extremely well considering it's age.
I've picked up several Fluke meters secondhand and they are as good as new. Tough, reliable and above all safe.

Regards
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