voltmeter

[89basscat]

i was wondering what kind of voltmeter you guys use to test ignition components? I was using a wavetech digital voltmeter but the service manual says to use a stevens or mercotronic, and i assume they are both old analog meters. thought a digital would be better.. any suggestions??

thanks
jim

[The Big Al]

FLUKE! The one and only!

http://us.fluke.com/usen/products/Fl...keUnitedStates

<TABLE cellSpacing=0 cellPadding=0 border=0><TBODY><TR><TD vAlign=top>Digital Multimeters > </TD></TR><TR><TD vAlign=top></TD></TR><TR><TD vAlign=top></TD></TR><TR><TD class=BlueHeadline vAlign=top>Fluke 73/77 Series III Digital Multimeter</TD></TR><TR><TD vAlign=top></TD></TR><TR><TD vAlign=top><TABLE cellSpacing=0 cellPadding=0 border=0><TBODY><TR><TD vAlign=top width=200>
</TD><TD vAlign=top width=10></TD><TD vAlign=top>All-round performers The model numbers Fluke 73 and 77 are an important part of Fluke’s reputation. In many years of service they have become the preferred models for a large number of professionals. The Fluke 73 and 77 offer exactly the right fit for a wide range of measurements. They are truly all-round performers. The 73 III is perfectly suited for many electronic applications and has the "classic" 70 series design with removable holster. The 77 III has all the features and functions for a wide range of industrial applications packaged in an ergonomic case with integrated holster. Both models come with the unique lifetime warranty.
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[The Big Al]

Model 73 is in the 150.00 dollar range and the 77 is in the 200.00 range

And you can find some deals on E-Bay

[Migalito]

Al,
do you need to use the DVA with these meters or is it built in?

[electricjohn]

Any digital multi meter with a 10 meg ohm (jfet) input will work. The faster the sampling the better. A fluke has 25 millisecond sampling.

[hsbob]

elect is right even a 20meg would be better. the 10 are available under 50 the 20s go for 100+. the is the resistance to current flow while measuring the voltage.

[Migalito]

I tried checking the voltage at the coils, with engine running at idle. The Merc manual says the voltage should be around 180V using the DVA. However, my voltmeter did not read that much voltage. It read 4V. The meter does have 10 Mega-ohms input impeadence but I'm not sure if it is a JFET. Has anyone tried this measurement using a Fluke or something similar without the DVA?

[j_martin]

The Merc meter is a DVA. A dva measues the peak voltage. It has a circuit that stores that value in a capacitor for the meter to read. You can make or buy a dva adapter for a standard meter, as long as it is sensitive enough.

A 100 volt, 1 millisecond pulse, 100 per second, will read 100 v on a DVA, and 10 volts on a regular meter. If the peak voltage is what counts, the 10 volt reading is useless.

Hope it helps.
John

[Migalito]

I found a thread that shows how to make the DVA. It is really a simple item to make so I am going to give it a try.

[eluder]

dva peak reading is needed.

[David Borg]

I found a thread that shows how to make the DVA. It is really a simple item to make so I am going to give it a try.

Can you post url plse as I couldnt get the search function working

thanks

[Migalito]

It was a post by baja200merk titled Peak Reading Voltmeter. Bill Rogers posted the schematic in that thread.
Did you login before you did the search?

[Migalito]

I found the parts to build my own DVA at a local eletronics parts house. I assemled it and tried it last night and it works just like it is supposed to. It cost me $1.00 for the parts plus the gas to drive to the parts house. Now, on to diagnosing my high speed miss....

[The Big Al]

I found the parts to build my own DVA at a local eletronics parts house. I assemled it and tried it last night and it works just like it is supposed to. It cost me $1.00 for the parts plus the gas to drive to the parts house. Now, on to diagnosing my high speed miss....

What is needed?
Exactly?

Al

[j_martin]

Any old rectifier diode, 400v or better, 100 ma or better. The 1n4004 is 400v, 1n4005 is 600v etc. (1 amp power rectifiers, 2 for a buck is a high price.)

An electrolytic capacitor of 400v rating or higher, 2 uf to 100 uf capacity.
The bigger number decays slower and is physically bigger.

a 1 megohm, 1/4 watt resistor to bleed the capzapitor so it don't bite you after you disconnect it.

tttttthhhhhaaatttsss all folks.

John