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Discussion Starter · #1 ·
hey gang,

can someone explain how you use a multimeter to check resistance and continuity. i have a meter, but have never used it for this purpose. manual tells me what to check, but not how to check it. Where do i put the black probe and where do i put the red probe for checking ignition parts such as wires, coil, pulse generator, etc. do i have to have the bike running to check anything? i am really pretty clueless. thanks for your patience in advance concerning your response.

howard 83 vt750c
83 gl 1100
 

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Your multimeter should have an ohms scale. Set it to that, and hold both the red and black probes together. The needle should swing up to full scale (or read 0.0 - 0.4 if you have a digital meter). If your meter has a knob on it to zero the meter, adjust it until you get a reading of 0.0 ohms. If the scale on your meter (if it's analog (with a needle!)) has strip of mirror on it, it's there to help you get accuracy. Close one eye, and look directly into the face of the meter so that the reflection of the needle matches up with the needle itself. When the needle is covering its own reflection, you know you're looking dead-on into the meter, and can best read it accurately.

Anyway, to test resistance, you have to send current through the device that you are testing. That means that one probe on your meter sends the juice out, and the other picks it back up, and moves the needle on the meter according to what it gets back. (Not perfectly accurate a description, but for our purposes, it's close enough.)

So, if you want to test your pulse generator, connect one probe on the meter to one of the pulse generator wires, and connect the other probe to the other wire. Resistance checks are not polarity-dependent (unlike almost anything else you'll ever check with your meter!) so red or black doesn't matter. Read the meter, and it will tell you the resistance.

The meter will have different scales in it for different tests, so be sure you are reading the numbers that correspond to the Ohms scale! (rather than the voltage scale, amperage scale and others)

A word of caution: if you measure the resistance of something that has voltage on it, you will destroy your meter. Examples would be a lit light bulb, the battery or the coil in a bike with the ignition on. When in doubt, use the meter to check the voltage on the part you are about to test to be sure it has zero volts on it before you test the resistance!

Have fun!
--Justin
 

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Discussion Starter · #3 ·
multimeter and continuity

thanks for the reply. i did, earlier, connect the meter to the pulse generator and got no reading. does the key have to be on? someone told me to test all my grounds. how do i do that?
 

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Not to sound like a wise-guy, but is your meter working correctly? When you connect both probes together, do you get a full-scale reading?

Is the battery in your meter good?

If you get nothing when you connect across the pulse generator, you have problems!

As a general rule of thumb, you should always test the resistance of something out of circuit. This means, disconnect it from the rest of the bike's circuitry by unplugging the connector. When you test something with the connectors attaches, you are not only measuring the resistance of the part you want, but also the resistance of all of the parts that that part is connected to, and you your results can be way off.

--Justin
 

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tubes_rock said:
If the scale on your meter (if it's analog (with a needle!)) has strip of mirror on it, it's there to help you get accuracy. Close one eye, and look directly into the face of the meter so that the reflection of the needle matches up with the needle itself. When the needle is covering its own reflection, you know you're looking dead-on into the meter, and can best read it accurately.
Someone is REALLY showing their age! LOL!

Don't worry, I STILL have a couple of my old Simpson's! :shock:

tubes_rock said:
If you get nothing when you connect across the pulse generator, you have problems!
One this to make sure is that the meter is set for the proper range of
resistance you are measuring.
If you are measuring something with a resistance that is 'off scale' it
may show open or it may show OL (overload) or ERR (error).
 

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Right, be sure to set the range right. When in doubt, and if your meter supports multiple ranges, use the biggest range first. That way you can get a ballpark figure. Once you get that, work your way down to the smallest range that you can use, as this will give you the best accuracy.

On my Digital meter, (and my Vacuum Tube Volt Meters too (how's that for age, litnin!)) I have several resistance scales. One is 0 - 2,000 ohms, one is 0 - 200k, the next is 0 - 2M. I start with the 0 - 2M (2,000,000 ohms) if I'm not at all sure what I'm looking at, and if it reads 0.17M ohms, I switch to the 0 - 200k scale for accuracy.

If your meter has a range that will measure 600 ohms, you should use that. If memory serves (and it sometimes doesn't!) the pulse generator should be in the 400 ohm range if it's working properly.

Litnin, I'm not actually all that old, just as a point of curio. I work on tube audio gear like guitar amps and stereo amps. I design and build a lot of my own equipment, and my work bench looks like it came straight out of the 50s. (Right down to the Tektronics 568 oscilloscope!) But when I get right down to it, I haven't broken 30 years old yet. Just born in the wrong era it feels sometimes!

--Justin
 

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Someone is REALLY showing their age! LOL!
But when I get right down to it, I haven't broken 30 years old yet. Just born in the wrong era it feels sometimes!
Justin

Ya fooled me too! I would have guessed you're older with your like of tubes.

The ole' VTVM! First meter I ever used back in the early '70's. My dad was into Ham Radio, his ham shack was ALL TUBES! He built most of his own gear too. I think my brother still has one of his old WWII vintage Hallicrafters receivers.

Read many of your informative posts and have posted along with you, especially like your sparky wisdom, I'm more mechanical, but muddle by with elexs.

Gumpy
 

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I bought my first meter, Simpson 260M VOM about 1980 with leather case, what a boat anchor. It still looks brand new because right after that I saw the first DVOM. Simpson's been on the shelf ever since.
 

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Gumpy, thanks for the kind words. I suppose that I shouldn't have let the cat out of the bag, but oh well. I've gone from "occasionally-respected" to "twenty-something punk" in 3.2 seconds. That's the beauty of the internet: no one knows who you are.

I dabble in electronics, music, computer programming, electro-mechanicals of all sorts. The beauty about all of these things is that that are all mechanical on some level. A guitar amp is nothing more than fire-engine built out of transformers and wires rather than pumps and hoses! And electronics is programming in hardware rather than with a compiler. If you can rebuild a motorcycle, you can program a computer, or build a television. It's the same mental process, but in a different medium.

For me, it gives me something to work on in the winter months, when I can't be outside bending wrenches.

The funny thing is that I'm writing network-management software here at my desk at work right now, listening to The Beatles on my original 1961 Zenith radio. A radio that was made before the British Invasion! And to top it all off, since we're two stories underground, I can't get a radio station to save my life, so I'm broadcasting The Fab Four using a home-brew FM transmitter from my iPod! Talk about a technology clash! But my Zenith sounds a lot better than my co-worker's new Sony!

On the ham bands, I'm N1YNX, if you ever run across the call-sign.

73s,

--Justin
 

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tubes_rock said:
...listening to The Beatles on my original 1961 Zenith radio.
You might like my radio.
We had an (I think it's a '35 or '36) Zeinth as the family radio, when I was growing up.

My parents had gotten it from my grandparents.

This is a very similar radio (not actually the one I have, but close).


I remember making trips to the drug store with tubes to put them in the tube tester.
If it was bad, just grab one from the shelf underneath and stick it in the slot.

There's nothing like a good old fashioned radio.
Today's modern electronics are indeed great, but they just don't match
the warm soft tone that tube radio has.
 

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Boy, did this thread ever get hijacked!

Litnin is right, there's not much that beats the tone of tubes. That's why I still can make decent bucks building new amplifiers for folks out of 1940s technology!

We had (wished we still had!) a 1936 Zenith. It looked a lot like the picture you included, but darker, and in rougher shape. It had a free-floating antenna inside the cabinet that you could turn, twist and angle to get the stations. It looked like a milk-crate with wire wrapped around it! Also inside the cabinet was a turntable that still worked, but would only play 78s. (of course, since 33 1/3s and 45s weren't invented yet, and I don't think the 16s were yet either.) But the electronics in it suffered deterioration beyond what my skils at the time could handle. The insulation from all of the wires had rotted off since it was a very early form of rubberized insulation. All of the wires were bare because of it. Someone (not me :eek: ) plugged it in and didn't know that there were a few dozen dead-shorts in it at 170 volts DC. The electronics went up in a puff of smoke, and that was the end of them. I could probably fix it today, but back then, I just gave it to friend who liked the way it looked in his living room and never planned on actually using it. He threw out the radio circuitry, and put a night-light behind the dial so it would give off that warm yellow Zenith glow. Oh well...

--Justin
 

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litnin said:
tubes_rock said:
If the scale on your meter (if it's analog (with a needle!)) has strip of mirror on it, it's there to help you get accuracy. Close one eye, and look directly into the face of the meter so that the reflection of the needle matches up with the needle itself. When the needle is covering its own reflection, you know you're looking dead-on into the meter, and can best read it accurately.
Someone is REALLY showing their age! LOL!

Don't worry, I STILL have a couple of my old Simpson's! :shock:

tubes_rock said:
If you get nothing when you connect across the pulse generator, you have problems!
One this to make sure is that the meter is set for the proper range of
resistance you are measuring.
If you are measuring something with a resistance that is 'off scale' it
may show open or it may show OL (overload) or ERR (error).
With a bakelite case for the win!
 
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