Film-Tech Forum ARCHIVE: Multimeters in the booth

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Posted by Ken Lackner (Member # 1002) on 02-02-2002, 01:27 PM:

Do any of you use a multimeter for any work in the booth? I supposed this would a apply more to the techs than the projections. But I want to be a tech, which is why I am currently studying electronics.

I went to Grainger to check out what kind of meters are available. I just wanted to get an idea of what's out there and the prices. The guy said he couldn't even begin to help me with selecting one unless I knew exactly what I needed it for - what measurements I would be taking and what ranges I would be using. So, what do you guys use your DMM's for?

About brand names. I know Fluke is really good. Are there others? Are there any to avoid? I'm currently looking at the Wavetek Meterman models 35 XL (almost sounds like a Simplex projector, eh? ) and the 2015 because I can get a good educational discount on those. Anybody know anything about these two meters? Thanks in advance for your help.

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This one time, at Projection Camp, I stuck a xenon bulb....

Posted by Will Kutler (Member # 770) on 02-02-2002, 01:37 PM:

Flukes are about the best you can buy. Personally, I have always prefered anaglog meters. And do not forget the amperage/current attachment!

Yes, a multimeter is definatly great to have in the booth! Cna be used to troubleshoot any electrical problem...but you must know how to use one correctly!

Be sure you know what you are doing with the instrument. I actually had one dumbass who thought himself a "badass" projectionist insist that the multimeter was a platter tachometer !

Posted by Dennis Atkinson (Member # 345) on 02-02-2002, 01:55 PM:

I have two DMM's.
One is easy to use / simple.
The other one has a manual you cannot believe.

Fluke is good, I have a Beckman I like also.
My fav option on a meter is
a beeper or tone feedback when checking continuity.
You don't always have enough light to see the LCD of the meter.

Dennis

Posted by Will Kutler (Member # 770) on 02-02-2002, 02:21 PM:

Whenever you use a meter, visual inspection of the component is also a must! On one ocassion, I had to work on a Christie SLC console where the contactor relay crapped out resulting in much burned up wiring. I used the meter to inspect all of the system components, and had to do an emergency run to ACE Hardware where I purchased new wire and terminals. One wire in particular tested ok, but my gut told me to replace it as the insulation had sustained a little heat damage. Well, I did not listen to my gut and reused that wire that tested good. The system ops checed ok once I completed repairs. About a week later, that lamphouse was once again having problems striking. I knew straight off exactly what it was. I replaced that wire, and all was good. Anyhow, once I removed that wire, I tested it and it still tested good. So the moral of the story is to use the meter, but also rely on visual inspection!

Posted by John Walsh (Member # 168) on 02-02-2002, 02:24 PM:

Fluke, Wavetek, Beckman, Simpson are all good meters. Fluke was quite aggreessive in their marketing a few years ago which is why you see many around today. Fancy meters include frequency, capactance, inductance, true RMS, so you could pay a lot for one if you want extra features. Many digital meters have overload protection (fuseless) on them to protect the meter if you, say, try measuring 240 volts while leaving it set to measure restance. I'd also get the protective cover (usually an option) to protect the meter if you drop or bang it somehow. I tend to avoid meters that require you to buy optional "attachments" that attach to the meter.

If you are buying a meter that will stay in the booth and used by several people, I'd suggest a cheaper ($40) analog VOM meter. If you are buying it for your own use, then get something good.

I've used a classic analog Simpson 260 (series 5) meter for almost 30 years. Has the right ranges for booth use. While the digital meters are tempting, I like having the analog meter to watch for strange things like having unexpected capactance in a circuit. But I admit it's a bit big to haul around.

Almost as important as the meter is: Get good probes/leads. Nothing's worse than trying to measure something and having to wiggle the leads to stay connected. Get pointy probes, alligator clips, hooks, bananna jacks, etc. Usually you can buy a kit with everything.

Posted by Brad Miller (Member # 2) on 02-02-2002, 02:33 PM:

Been there done that Will and I couldn't agree more. A tip to Ken, if the wire that looks charred is "extra large" but still tests ok, definitely replace it! That sucker will be carrying a lot of current and a damaged section will keep the current from flowing freely. Also you can get replacement wire and clamping connectors at big places like Home Depot, but don't be surprised if they don't melt apart within a week. Many electrical items that the Home Depot sells is not quite up to what your lamphouse is capable of doing to it. Make sure whatever you are doing the cable and connectors can handle the load. When in any doubt, get an experienced tech to make the call or contact the manufacturer for an opinion or their replacement cables.

BTW, you should invest in a digital camera if you are going to get into any tech work. Many times a description just isn't good enough, but a quick email with pics will allow another tech to be able to see what your problem is and talk you through it.

And don't touch that big round cylindrical thing!!! Them capacitors can be overly exciting to the unsuspecting. (No, I have yet to actually shock myself on one, but have seen well seasoned techs do it.)

Posted by Will Kutler (Member # 770) on 02-02-2002, 03:08 PM:

Brad...

Thanks for mentioning about wire ratings. Wiring and hoses have info printed on them. This info is both the spec ratings and a line that will tell you if you are twisting the new wire or hose. The new wire that I installed into that lamphouse met or exceeded the origional equipment.

Posted by Gordon McLeod (Member # 33) on 02-02-2002, 03:32 PM:

Metrex also makes good (and disposabley cheap) Digital Multi Meters

Posted by John Anastasio (Member # 607) on 02-02-2002, 03:58 PM:

I've used both Simpson and Fluke. They're both great meters, but one's a self-ranging DMM and the other's an analog. I find that the analog meter is a lot easier to see. I use 'em both, but if I was going to buy a new meter today, I'd buy the analog. If you're using it with audio circuits, you can see the meter move. With a DMM, all you see is numbers changing....if you can see the numbers at all.

Posted by Randy Stankey (Member # 64) on 02-02-2002, 04:08 PM:

Whenever I bought wire and connectors from a local "consumer" outlet like Lowes or Home Depot I would always buy it the next size larger or the next grade higher than I thought I would need. (If practical).
I figure if the equipment in question used 14 AWG and I used 12 AWG it wouldn't hurt anything and would provide a safety margin against the same problem occurring again. On the other hand buy wire that's smaller than you need and you're asking for trouble.

On meters, I'd buy Fluke. (If it works it's a Fluke! )
You'd need to be able to measure AC and DC voltage up to 240+ volts. (I believe most meters are rated up to 600 or 1000 volts, depending on the kind you buy.)
You'd need to be able to measure current up to, what, 100 amps? You might need to buy an accessory called a "shunt" to measure current that large with some meters. If you buy a clamp-on (ring) probe you won't have to worry about that so much.
You'll need to measure resistance/continuity. If you get the kind that has diode (and other component checking) functions built in to them it makes your life a lot easier.

Every booth needs to have a good meter handy even if the staff don't make a lot of their own repairs. It will save your ass many times to have one handy when a diode blows or when an unseen breaker trips off.
You can teach one or two of the "smart people" in the building to use a meter to test for voltage and how to check a diode. Once you have somebody like that, (IF you can get somebody like that ) it can save you a trip and potentially get the show on screen much faster. You can get that person on the phone and tell them, "Use the meter and tell me if there is voltage between 'wire A' and 'wire B'."
At the very least you can use that to tell if the call is a real emergency or if it's one that can wait until you make your next rounds.

Posted by Jeff Stricker (Member # 224) on 02-02-2002, 04:19 PM:

You can't beat the classic Simpson 260 for all around
troubleshooting. It won't have the accuracy of a DMM,
but for checking continuity, diodes and measuring
most voltages it's just fine. Also watching the pointer
movement allows you to make adjustments like bias
settings intuitively. (It's difficult to judge
increases and decreases by looking at flashing
LED or LCD displays.) A good "260" can be found in the
used market for $30 - $40.

Posted by Frank Angel (Member # 248) on 02-03-2002, 10:17 AM:

Agreed -- there's something very human about that swinging needle....analog over digital. Hmmmm, that's getting to sound familiar.

Posted by Dave Macaulay (Member # 813) on 02-03-2002, 11:33 AM:

You're kidding about the Simpson 260, right?
It is a fine analog test meter, but it's the size of a lunchbox, heavy, and quite delicate. This is a bench meter, not one to use on or in a projector and particularly not one to travel with.
I've used the 260, other analogs, and digital meters. I carry a Fluke 87 that's small, light, and near bulletproof. Thee is no extra feature of the analog meter that I miss or need - and I use some features in the 87 that no analog has.
Not needing batteries to measure voltage and current is a sweet deal, but I'm not giving up half my toolbox to a 260.

Posted by Ken Lackner (Member # 1002) on 02-03-2002, 12:48 PM:

Thanks for all your input!

We have Simpsons -- perhaps even the 260, I don't remember -- in the electronics labs at my school. I prefer the BK Precision DMMs that every station has.

My booth already has a very cheap analog meter. I am looking to buy one for myself. Are true RMS and frequency going to be measured in the booth? That's the main difference between the Wavetek 35 XL and 2015 that I mentioned in my first post. (I edited the first post to include links to those models on the Wavetek website.) The 2015 looks really nice, but it's twice the price, even after student discount.

So what do you guys think?

Brad, thanks for the tip on the caps.

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This one time, at Projection Camp, I stuck a xenon bulb....

Posted by Matthew Bailey (Member # 601) on 02-03-2002, 12:57 PM:

My brother has thic catalog of surplus reconditoned test equipment.
I wonder how much a reconditioned RCA or HP analogue meter would sell for.

Posted by Paul Mayer (Member # 355) on 02-03-2002, 03:42 PM:

I also have a Fluke 87 which is a true RMS meter. I bought it when I had a project going to check and adjust the curves on a bunch of theatrical stage dimmers (SCRs or triacs produce non-sinusoidual outputs when they're not set to full intensity, hence the need for an iron vane or true RMS meter). Other than for setting the curves on house light dimmers, I've never needed true RMS metering in a booth; frequency display was occasionally handy for checking playback speeds (admittedly, I've not done as much or as deep booth engineering work as some of you have). The 87 also has a bargraph display which, though not as fine as a good ol' d'Arsonval movement, is better than a numbers-only digital display.

But I have used Fluke's Hall-effect DC current clamp accessory quite often. It provides reasonably precise measurement of DC (or AC) currents up to 500A. Great for double checking suspect lamphouse current meters up to Omnimax size loads, or for balancing loads in 3-phase installations.

Remember, if it works it's a Fluke...

Paul
SMPTE Hollywood Section
Unemployed mercenary film/video projectionist/engineer
"Otaku wa tsurai yo" <-- Yeah I know, bad pun. Sue me.
It's tough being a fan!

Posted by Steve Guttag (Member # 268) on 02-03-2002, 03:59 PM:

As a travel meter, it is pretty hard to argue with a DMM for the everyday chores.

I, like others, have settled on FLUKE. For a true-RMS you into the 87 series (and higher). They are not cheap, but then again, you won't have to be trading them out very often either so think of it in the cost/year sense. I carry a FLUKE 87 with me where ever I go. I don't know if you really need the true-RMS feature in your line of work but if you feel you need it, then the 87 or 187 might be worth looking at. It also has a back-light feature so working in dark areas is not a problem.

There was an analog meter that folded up ( I believe that it was made by BBC and distributed in the States by SMART devices) that I might make room for if I had one.

The problem is, in a tool box, space is a premium so everything should have a good purpose and take up as little space as possible. If your career is depending on your performance, don't settle for junk, it will bite you in the long run.

Now on the bench, that is another story...I always have both analog and digital...If I'm just looking for a number, then I grab the digital probes...if I'm adjusting something, then the analog wins hands down. In fact, my work bench has two-analog meters, an AC voltmeter (reads from less than a millivolt up to 300 volts and also reads in dB..has a mirrored scale to prevent parallax errors too) and I also have the bench tech's old standard..the VTVM (yes with vacuum tubes). As most VTVMs go, when reading resistance, full-deflection is infinate and 0 = no deflection...that is when the probes are not touching anything, the meter is pointing all of the way to the right.

Now on the analog vs digital debate (seems to happen in most industries, doesn't it?)...one thing I hate about DMMs is the perceived accuracy. While in college, students always preferred the digital meter because it was sooooo accurate. Baloney. Ever read the spec sheet on a DMM (or any meter)....just because the meter says it is 20.23 volts that doesn't mean it really is 20.23 volts. Read the spec on the DMM you will find that the accuracy is expressed as a percentage of the reading PLUS a percentage of the range you are on! It isn't uncommon to have two identical meters read different and be within their stated accuracy.

Many readings in life you only really need to be within a factor of 10...that is, is it 5 volts or .5 volts...if the meter comes up near the "5" on the scale, it is good enough (this is not true in all applications, for sure, but as I said many times it is). If this is the type of troubleshooting one is doing (looking for the failed part) then an analog meter might be considerably faster than waiting for the digital meter to settle for each reading.

The problem with analog meters for field work is that they take up too much damn space.

I must say, I never was too fond of Simpson meters, the 260 included. I do have one on the "recone bench" for setting the amlifier output voltage when testing speakers. They are not horribly accurate, can load down the circuit under test (depending on the circuit, of course), don't have many ranges and such. They are just one's basic analog meter that does fine for my "within a factor of 10" measuring but I wouldn't do anything that you want accurate with it. I find it amazing that it is still in production as one of the last hold outs of the analog meter era and it sell for a rather hefty price (rivals some high end DMMs). Clearly, as has been stated here, the Simpson 260 has its fans and following and more power to them. It would take up a bit too much space in the tool box though.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Steve Guttag (Member # 268) on 02-03-2002, 04:02 PM:

Oh yeah, a clamp-on ammeter can be VERY handy. I always carry one though I didn't go for the "attachment" approach. If you get one, make sure it will read DC amps as well as AC amps.

Steve

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"Old projectionists never die, they just changeover!"