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ContinuousWave: Small Boat Electrical
|Author||Topic: Decent Multimeter|
posted 09-02-2007 11:33 AM ET (US)
Two days ago while attempting to troublshoot the power to my Lowrance LGC-2000 GPS antenna I found my older Radio Shack multimeter to be almost useless. It would be more correct to state that I found the probes to be too large for the task for me.
I checked all the likely suspects such as connections and in line fuses and on/off switch. All passed the visual test. I was then able to obtain a 12 volt reading across the switch. However, at the antenna connector output pins I was unable to get a reading. Aw shucks, do I really have to undo the harness wiring and look for issues? Just for fun I check the fuse again. It's blown. Replace the fuse and attempt another reading at the connector. Same story. This happens twice more. I'm almost out of fuses. Check it again and this time I can see the arc down in the connector where I've managed to get across the pins.
Replace the fuse again but I know when I'm whipped. Between my fingers, the very small connector, close together multiple pins, and robust probes I can't seem to get there from here.
I've concluded (perhaps mistakenly) that current is present in the connector and that it is almost certainly 12 volt and at the correct pins. So, off to Lowrance goes my antenna for warranty repair or replacement. I hope that's the problem?
posted 09-02-2007 02:24 PM ET (US)
The Boston Whaler Montauk of multimeters has for many years
been the Fluke 77. (it might be the 177 or some-such now).
Built like an anvil, accurate, and has plug in probes so you
can use the RIGHT probe.
Like a Montauk, not cheap. I paid about $150 fifteen years
posted 09-02-2007 07:03 PM ET (US)
Thank you for the recommendation. I seldom use a multimeter but when I want to use one it's important to me to be able to use it properly.
I see Fluke instruments hanging from the belts of a lot of technicians. If they are buying such an expensive line of goods there must be a reason.
posted 09-02-2007 11:03 PM ET (US)
The Fluke meters are very fine meters, but, as Chuck and everyone having one knows, they are expensive. Prior to my retiring, I purchased or approved the purchase of many, many Fluke meters. I have two, one in my shop and one in a toolbox in the pickup, but I have a bit cheaper (but excellent so-far) digital multimeter from Sears (around $50 - $60 as I recall) in the boat toolbox.
Get the best digital multimeter you can afford. Don't wait until you need one to think about getting one. --- Jerry/Idaho
posted 09-05-2007 11:23 PM ET (US)
I use the Fluke 187 VOM and the 336 current clamp which will read dc currents too. Great stuff for troubleshooting.
posted 09-06-2007 09:23 AM ET (US)
Good info, thanks. Agree that current readings can be very useful for troubleshooting systems. I assume the 336 is a plug-in to the 187. Is the 187 similar to Chuck's 77 or 177? Do you recall the approximate cost of the 187 and 336? If not, don't go to any trouble to look it up. I'll find out soon enough!
posted 09-06-2007 05:09 PM ET (US)
Like Butch I've found my Radio Shack multimeters turn to junk alarmingly fast, but unlike Chuck I couldn't bring myself to spend three figures on a device. After some looking around, I bought an Extech MN26T ("[Digital] Autoranging Multimeter with Capacitance, Frequency, and also Temperature") from Amazon.com for $32. I got it for $8 off -- I think the regular price is $39.99. I like it so much that I keep one on the boat and got a second one for home. It feels more solid than the Radio Shack stuff I've owned. In addition to other test functions, I'm assuming or hoping that I can use the frequency function as a spot-check tachometer (by attaching the leads to the back of my tach), but haven't gotten around to trying this yet.
posted 09-06-2007 09:16 PM ET (US)
In defense of Radio Shack multimeters: The on-the-boat meter
is a tiny Radio Shack unit (think fat business card case)
that I bought before the whaler when I discovered I'd left
the usual traveling unit at home. It's still going strong.
The only downside is that it takes a slightly weird battery,
but it's only slightly weird, and the same as what Linda's
UW cameras use, so there's always some spares around.
I think it was about $20 ca. 1991. It's been to Belize (twice), Turks and Caicos, Australia (thrice), Fiji (twice),
posted 09-07-2007 01:37 AM ET (US)
I think the 187 was about $350 and the 336 about 325 or somewhere close to it. The 336 clamp does have a vom with
test leads built in too it. This 336 meter reads up to 600 amps both ac and dc. I do have a small 150 amp clamp for the 187 but it is ac only so not much help on a small boat. For anything above 10 amps the 336 fills the bill on dc systems.
If I had only one meter for the boat it would be the 336 with a good assortment of leads and clips. Another thing to have is an infrared tempeature gun, good for wheelbearings if you travel alot. Fluke makes some meters wih less features for less money and are still very accurate too.
Chuck, making up the cigarette lighter plug is a great idea. I will make one this week.
|Tom W Clark||
posted 09-08-2007 11:38 AM ET (US)
Interesting coincidence, or maybe just Whaler owners have similar tastes? As it turns out own an old Fluke 77, which, as Chuck pointed out, is very tough.
But I also own a little cheapy multi-meter I bought at, you guessed it: Radio Shack back in the 1980s for about $10. It lives on my boat now because it is so comapct and it is still works as well as the day it was new.
posted 09-08-2007 06:34 PM ET (US)
I wasn't going to pipe up on this one, but now that you did Tom, I have a Beckman HD-153 for my more serious needs.
The now $17.98 Radioshack multimeter is the only one on my boat. It performs any analog troubleshooting that I've come across.
posted 09-09-2007 11:13 AM ET (US)
FLUKE digital multi-meters were the gold standard for a long time, and they still hold the very high ground (and price). However, there are many much less expensive meters on the market now which give good performance.
With test equipment there are two important requirements:
First, nothing is more discouraging than trying to diagnose an electrical problem and having unreliable test equipment. If you have to first repair the test equipment before you can use it to repair the device you want to test it can be frustrating to say the least.
Second, when test equipment is used by more than one person it has to be extremely rugged and well built. Someone once observed that a 'scope probe in a laboratory situation with many users lasts about two weeks, while the same probe or even a cheaper one used by just one person will last twenty years.
In this regard, I think you can find a suitable digital multi-meter which is less expensive than a FLUKE for your own personal use. However, there is nothing wrong with buying a FLUKE, I happen to have two of them myself.
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