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 Post subject: DMM with Cx and Lx modes???
PostPosted: Dec Thu 23, 2010 4:19 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
I’m a hobbyist not a professional electronics guy, I never had what it takes to work in electronics and never will have it. But, I do have fun playing with this old stuff and manage to suffer thru a few restorations each year. About 10 or 15 years ago I bought a Wavetek DM27XT for about a hundred bucks because it was the only meter that was not only a DMM but one that had scales for Inductance and Capacitance also Now I’m aware that it isn’t gonna check for voltage breakdown at 600v or anything like that, but it did come in handy for an amateur like me to check those cryptic values that are stamped on those caps in the junk drawer on the end of the bench. I did give me an idea of the inductance somewhat also when I was playing around with crystal sets and such.
Now to get to the point. The Cx and Lx modes quit working last year and I’d like to find another one that has the same capabilities. Or maybe just a dedicated meter that I could get a rough measurement of Capacitance and Inductance.
Is there anything out there that is in the price range of an old blue-collar retiree, hobby radio fixer upper??

Denny Graham
Sandwich, IL


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 Post subject:
PostPosted: Dec Thu 23, 2010 4:36 am 
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Joined: Nov Sun 07, 2010 7:16 pm
Posts: 336
Location: Rochester, MI
I bought a Triplett 2103 a couple years ago for around a hundred. In addition to volts, resistance and current, it has a frequency counter, capacitance function, inductance, signal generator, temperature, logic scale and transistor tester. It also has an rs232 interface so you can log data to a PC. 3 1/2 digit.

My only complaint is it doesn't have a diode junction check. Well, it might, but I haven't found it; I just use an old BI meter for that.

Both of those meters also have auto-off functions. I won't buy a serious meter without that.

Most meters these days have some combination of those functions; you shouldn't have to look too hard to find one in your price range (whatever that is)


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 Post subject:
PostPosted: Dec Thu 23, 2010 12:44 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
Apparently the 2100 series has been discontinued Paul, couldn't get a price listing for any on Triplett's site. None of the 2100 series had the inductance mode either.
I wasn't aware that the Triplett name was still around. That was a good instrument back in the day but I'll bet dollars to doughnuts that the name is just pasted on instruments that are now made in china or India. To build an instrument here in the USA that would have all those functions on it would probably cost you $1500.
For this old hobbyist, the hundred to hundred fifty dollar range is more my speed.
I did get a bargain on a Fluke 75 series II multimeter a few years ago, a deal I couldn't pass up. Funny but I used it for my back up to the Wavetek because it had limited functions, go figure.
I really wish I could find the problem with the Wavetek because it did everything that I wanted. Something like a bad cap is most likely the problem but I'm not very good at trouble shooting,, especially anything solid state.
So I've been on the net and am I'm still looking for more suggestions.
Denny Graham
Sandwich, IL


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 Post subject:
PostPosted: Dec Sun 26, 2010 6:37 am 
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Joined: Dec Mon 20, 2010 7:23 am
Posts: 483
Location: Minneapolis, MN
You might have checked for this already but you didn't....open the meter and check for an open fuse.
It's just a thought. I had some other digital meter that when the fuse that looked like it was just for the amp range blew, it disabled some other functions as well.

Mark


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 Post subject:
PostPosted: Dec Sun 26, 2010 6:57 am 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 6156
Location: Santa Rosa, CA
I zapped my Wavetek DM27 a few years ago. Fortunately, I killed only the voltage ranges. C and L are fine. I don't think it's a fuse issue.

Rich


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 Post subject:
PostPosted: Dec Sun 26, 2010 12:31 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
Well guess what, I had changed the battery right after I started having problems with it the first time, thought maybe that might be the problem. At the time I also pulled the back pcb off and cleaned the wipers and all with a pink eraser and some alcohol, looked everything over for a broken or burned component, all looked fine and none of that helped.
Last night I did the same thing again but this time I noticed that the large fuse has slid over and was touching the small fuse. Lacking a schematic I don't know if this could be the problem but I slid it back to the center of its clips and now the meter is working in all of its modes. I might have dropped or bumped the meter and the fuse slid over and shorted.
I've looked for years for a schematic for this meter but never did find one. Wavetek apparently stilll markets this model but the sales information for meters is so screwed up it's hard to tell what is or isn't avalable any more. I spent hours on the internet just trying to find a source for another one and never did.
Denny Graham
Sanwich, IL


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 Post subject:
PostPosted: Dec Sun 26, 2010 5:02 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 3754
I know there will probably be calls of Blasphemy, but I got this meter (item# 37772) a few months ago at Harbor Freight for $25 and checked it out against my GR-1650 LCR bridge and my HP-3456 lab meter, and its pretty decent for the price.

Image

Does the usual plus frequency, XL, XC, HFE, and Temp. with supplied probe.


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 Post subject:
PostPosted: Dec Sun 26, 2010 5:32 pm 
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Joined: Jan Thu 14, 2010 12:26 am
Posts: 597
Location: Tucson, AZ, 85757
Guys,

I'm on my second one of these (Having accidentally burned one up connecting to over +1200VDC working on a Scope). I really like the tilting screen feature and the large led.


JP


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 Post subject:
PostPosted: Dec Sun 26, 2010 5:51 pm 
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Joined: May Mon 18, 2009 5:55 pm
Posts: 2443
Location: Erie, PA
Wavetek as it was known has gone through at least two transitions that I know of. They partnered with Datron of England, and that eventually became Wiltron. Then Wiltron was absorbed in to the Aeroflex group of Germany where it stands today. I don't think there are any multimeters made under the Wavetek name any longer.

As I found out the Harbor Freight multimeters when new will compare favorably measurement wise with calibrated multimeters. The only scales I found on HF's cheapest $4 job that were a hair out of spec were the two AC volts scales. I know their more upscale models are made by Mastech, who make cheap multimeters under a lot of names. I can honestly say that for their price, they are better than what you might expect. I have one that is used for any sacrificial applications where I don't really care what might happen to it. The little $4 ones are great to carry in the pocket at swap meets or garage sales where a quick ohm meter check on something can tell you a lot about a piece of junk or some components you are thinking about buying. If you drop or lose the meter, no huge loss.

-Mark-

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 Post subject:
PostPosted: Dec Sun 26, 2010 8:48 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 6156
Location: Santa Rosa, CA
I'm heading for Harbor Freight.

The 37772 model is on sale for $19.95. It doesn't measure L and the C range is a bit low for electrolytics, but how can you go wrong on the price?

They even give you a manual with a parts list and schematic!

http://manuals.harborfreight.com/manuals/37000-37999/37772.pdf

I like the little $4 HF DMMs and usually get them free when I buy something else.

Rich


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 Post subject:
PostPosted: Dec Sun 26, 2010 11:11 pm 
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Joined: Dec Mon 20, 2010 7:23 am
Posts: 483
Location: Minneapolis, MN
Denny I'm glad you got your meter working :)

The harbor frieght one mentioned later in this post is one you have to be careful if you take it apart for servicing. This is especially true for the range switch. (If you want to clean it) If you look when you take out the board you will see what I mean about the switch. Also the contacts are little leaf brushes that contact the board for the proper range. Not all the slots are occupied. Also the alignment peg for the range knob is sqaure so if you didn't observe what range you are on when you took the board out you have 3 wrong ways to get it back on.

I have a couple of these too..so no big loss if an accident or lose it.


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 Post subject:
PostPosted: Dec Sun 26, 2010 11:20 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 3754
OOPS!!

Wrong again.

You're right rich, it doesn't measure inductance, the Xc cought my eye when I glanced at the meter and I just assumed it did Xl as well.
Image


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 Post subject:
PostPosted: Dec Mon 27, 2010 12:33 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
Hey that's ok, it's really caps that I want to know the value of that I need in a DMM. I got a terrable memory and can never remember what those values mean that are stamped on the cap. For twenty bucks I think I'll pick a couple up one for the garage and one for the shop.
I have picked up a couple of those four dollar jobs and they are good enough for the glove box or tool box. Use them a lot when I just want to check contenuity of a bulb or whether a battery is dead.

Tks,

Denny Graham
Sandwich, IL


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 Post subject:
PostPosted: Dec Tue 28, 2010 1:30 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
Picked up a couple of those $19.95 Harbor Freight 37772 meters today, but one thing puzzles me. The Cx socket is simply two slots that you can plug a cap into. Any suggestions for using test leads so you can check a cap at some distance from the meter???

Denny G


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 Post subject:
PostPosted: Dec Tue 28, 2010 1:57 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 6641
Location: Minneapolis, MN USA
I don't own one....could you make an automotive blade type fuse fit the cap socket ?
You may be able to use that to create a "jack" for soldering test leads to.

Keep in mind there I don't see a zeroing control and the extension leads will add some capacitance to the reading. Lack of zero control may be why there is no conventional sockets for cap extension leads.


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 Post subject:
PostPosted: Dec Tue 28, 2010 3:52 am 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 3754
Denny,

Did yours come with a thermocouple? I think I saw in the manual that now its an accessory.


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 Post subject:
PostPosted: Dec Tue 28, 2010 5:39 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2500
Location: NE Fla. 32043
Denny Graham wrote:
Picked up a couple of those $19.95 Harbor Freight 37772 meters today, but one thing puzzles me. The Cx socket is simply two slots that you can plug a cap into. Any suggestions for using test leads so you can check a cap at some distance from the meter???

Denny G


On My cheap-o DMM, I soldered a couple of gator clips to a couple of those flat metal nail thru picture hangers after bending them straight. I plug those in the slots and clip the cap in the gators jaws.

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Gary


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 Post subject:
PostPosted: Dec Tue 28, 2010 6:13 am 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 6156
Location: Santa Rosa, CA
My old Wavetek DM27 used the leads for capacitor tests.

My leads added about 50 pF to the readings on the most sensitive range. I estimated this by checking a 100pF silver mica.

The Wavetek had no compensating control.

Rich


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 Post subject:
PostPosted: Dec Tue 28, 2010 1:59 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2185
Location: Sandwich, IL, USA
Dale and Rich, that’s Wavetek also, it uses the test leads to measure Capacitance and they add around 40pf if they are separated, that changes of course, depending on how far apart they are or whether they are twisted. I’ve put a little reminder sticker on the meter so when I’m checking a cap in the lower range I take that into consideration. And no, this HF meter doesn’t have any provision for zeroing out an adaptor or leads so one would have to make note of that and compensate for it. I don’t want this Hobby to turn into a Carrier, and because of that my ability as an electronics repairman is quite limited so nothing that I ever work on is so critical that a few puff in either direction would make a noticeable difference. I never put a radio up on the bench with more than 6 tubes and if they’re SS I give them a pass also, I’ll leave that complicated stuff up to the experts, I‘m just an old dumb mechanic.
Yeah Gary, I was thinking I’ll just make up a set of leads with a couple of spades crimped on the end and maybe some small gater clips with the same.
Mike, I downloaded the Manual from HF’s site before I ran in to the city and picked up the meter. I noticed that “optional accessory” note also. I couldn’t find any listing for ordering them on their site and the kid I talked with on the phone didn’t even know what a DMM was. But, when I got to the store and looked at the blister pack, a ‘K’ type thermocouple was bundled with the test leads. All of the thermocouple plugs that I’ve used in the past had flat blades. The blades on the plugs packaged with this meter had a slight bend longitudinally down the middle, I suppose to make them fit tighter in the socket. They in fact, fit so tight that I couldn’t even push them into the sockets in either meter. After I flattened out the blades in the jaws of a needle nose they slid into the sockets nice and snug.
This was just another example of how the Chinese made products are always/every time, just off enough to make people call the stuff junk. I keep saying if they would only put a tiny bit more effort into QC and the finished products; they would have some half way decent imports. I restore early 50’s Chevy trucks and the majority of our reproduction parts are off shore production. Almost all of the stuff is close but no cigar, like they put a lot of effort into making dies for forming the parts and then ship them out without the right size holes or the OD of a pin is off by a few thousands and it won’t fit a boss or the chrome bumper that you get is formed perfectly and chrome looks great but they neglected to take three minutes and deburr the edges which now look like a hacksaw blade, or the sheet metal part is formed perfectly, an exact reproduction of the original but the metal is half the thickness.
So how does that rant relate to these HF meters? Well when you first look at this meter you ask your self, “how in the world can they make this for twenty bucks and still make a profit on them?” Then you open the blister pack and start to see, things like the way the before mentioned plug fit’s the socket, the lack of circuitry so you can use the test leads for measuring the caps, the test lead jacks are not smooth, when you plug them in they feel rough and you just know that it’s only a matter of time before one of them fails, the dial also feels rough, a little loose and just kind of cheap when you spin it around. The on/off and hold switches also have that loose cheap feel to them. As with most cheap meters, the leads are not rubber but plastic and the wire is probably 18ga. 7/26 rather than 18ga. 41/34 which means that they’re stiff and will probably never straighten out, The case looks real nice but it’s thin and you can tell it’s made from a cheap brittle plastic and is going to shatter the first time it gets dropped. Oh, one thing that doesn't show up in the picture, this meter is about twice the size of my Fluke and Wavetek DMMs, it's a BIG meter.
But that‘s why I bought a spare, after all, what can you really expect for $19.95.
Denny Graham
Sandwich, IL


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 Post subject:
PostPosted: Dec Tue 28, 2010 3:54 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 3754
Hi Denny,

You can owe your soul to the Snap-on guy:wink: or pay cash for acceptable tools somewhere else, and to me this is one of those acceptable tools. I've had hand held flukes in the past, and they're OK, but to me, not worth the extra money. If I made my living in the industrial service arena, I'd probably have a different opinion though.

This is a cheap LC meter I bought maybe 20 years ago, and Its been dropped a few times. It seems to have the same type case material as the HF meter, and I suspect it may actually be Noryl, a pretty tough plastic. It also appears to have the same test lead jack as the HF unit. Image

As you can see, it idles at three and a half puff, but no big deal.


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