Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: rafe on December 01, 2021, 04:34:41 pm
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I was testing ohms on resistors, and I kept getting low readings around 25% low, so I started testing unused ones and it the same thing. They have been sitting around a few years ....Should I trust the meter or the resistors....does the ohm setting fail? It's an Ideal meter
Edit by sluckey... fixed that HUGE pic.
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It's BIG
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I was testing ohms on resistors, and I kept getting low readings around 25% low .... does the ohm setting fail? ...
There's usually a battery inside (even on old VTVM meters if they do not get plugged into the wall). The "Ohm" setting could very well be a "Volt" measurement, but using the internal battery to supply volts/current through the resistance being tested.
When meter-readings are very-wrong, try replacing any battery first, then re-assess. Otherwise, it could be a calibration issue.
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it could be a calibration issue.
A gear geek usually has a set of "standards" to measure against
10 1% Mil spec resistors all the same value
12vdc verified by 10 meters
.....
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I had put a new battery in it. So, it's not that AC and DC voltages seem OK even put new leads on it same results. I am down to just that meter so I think I'll pick up another one. I was going to use my tube meter but I can't get the needle to zero.......I may play around with that tonight. Thanks for the reply
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What Shooter says, but with a twist.
I have a set of Vishay Dale Mil-spec 0.1% resistors, from 1 ohm every decade to 1M. Whenever my cheap meter looks off, I test.
Sometimes my meter will be off when testing the low values, but "ok" on the higher values. No idea why that might be, but it is fair to say that my DVMs are not the expensive brand. Maybe I should splurge on a Fluke.
Anyway, the 0.1% mil-spec resistors are very reliable and definitely more accurate than any measuring device I have.
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Use your other meter to test the battery.
A man with two watches never knows what time it is, you need 3 'working' meters.
Meters read high on sub-Ohm resistors because of stray resistance in switching, fusing, leads, and contacts. What does it read if probes are shorted together? (But I have had a meter which "auto corrected" by just rounding any low reading to zero...)
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"Use your other meter to test the battery." I was down to one meter, I bought a new battery and it didn't solve the problem, however I tested the old battery and it was low . I found a harbor freight giveaway and have good readings on the ohms so it's my meter. I took it apart and cleaned it but no luck the voltages appear correct as far as I can tell 117ac at the wall and 400dc on the Marshall. I guess meters don't hold up like they used to its 6 or 7 years old.
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"What does it read if probes are shorted together?" It fluctuates and takes it's time dropping to zero sometimes it stays at .3 .2 or .1 ....I have changed leads..... same thing
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"What does it read if probes are shorted together?" It fluctuates and takes it's time dropping to zero sometimes it stays at .3 .2 or .1 ....I have changed leads..... same thing
First thing to do .
1- It test both probe/ lead
2- It test meter reading
IMO if battery was dead or to low you won't see digit or digits will be very dim.
Do you see corrosion deposits on the 9 volts battery terminals ?
After several years it should be checked and the battery should be replaced before it leaks and damages the device
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It had some corrosion on the battery tabs on the DVM , It has metal strips not the snap on connection . The voltages seem good it is just way off on the Ohms . I don't know if it is worth having it repaired or calibrated, probably not. I am now relying on my free harbor freight for ohms
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You can wash corrosion ( and save connector ) with with a mix of baking soda powder and water, more baking soda than less. I use old tooth brush.
Rinse with water.
After fews months corrosion may come back, not always, check it and clean it.
When it happened and after it dry, I put some petroleum gel on contacts
Voltmeter ; good deal on Amazon;
https://www.amazon.ca/Multimètre-automatique-crocodiles-multi-testeur-rétroéclairé/dp/B06ZZG2F2N/ref=rvi_1/140-8892923-0132704?pd_rd_w=b8zQG&pf_rd_p=8b4d8c20-8e51-4634-a76f-c00a1995a502&pf_rd_r=FHV7A30PF8V63K2PVC82&pd_rd_r=73ea2102-e7df-4934-9c16-ce2f78dbfdbc&pd_rd_wg=ScTvw&pd_rd_i=B06ZZG2F2N&psc=1
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Do tests ; reply #9
It say all.
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Voltmeter ; good deal on Amazon;
That is a lot of meter for $20! Here's the US Amazon link...
https://www.amazon.com/Ranging-Digital-Multimeter-Battery-Alligator/dp/B06ZZG2F2N/
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Voltmeter ; good deal on Amazon;
That is a lot of meter for $20! Here's the US Amazon link...
https://www.amazon.com/Ranging-Digital-Multimeter-Battery-Alligator/dp/B06ZZG2F2N/
$1 more than mine :laugh:
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That IS a real good deal and for a Jackson! Wow. Being curious I ordered a black one..
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I have gotten two of my cheap meters to work for me and honestly .... I am not really happy with the digital world of meters. I kind of like this one and wondering what you all think of the specs on Gardner Bender 19-Range Analog Meter-GMT-319 - The Home Depot (https://www.homedepot.com/p/Gardner-Bender-19-Range-Analog-Meter-GMT-319/202867893#product-overview) think it will do everything I need a meter for I really liked my old Micronta. I have a desktop Simpson 266 but it's playing possum on me might just be a tube or a cap ..... I will dig into that or perhaps even send it off for repair. That one is probably worth saving. I put a cap in a few years back and really liked using it Thanks and Regards Rafe
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I have gotten two of my cheap meters to work for me and honestly .... I am not really happy with the digital world of meters.
It's because you may not use good one. Try a Fluke 175 and you'll throw you analog meter in garbage and many digital one.
Or it is because you may not know how to use it ?
I also have a Klein CL3100 ( $90)
My fluke cost $400, it is day and night with the Klein. The Fluke 10 times more expensive, 1000 time better
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I kind of like this one and wondering what you all think of the specs on Gardner Bender 19-Range Analog Meter-GMT-319 - The Home Depot.
Typical functions and accuracy for a VOM. 20,000Ω/volt sensitivity is poorly suited to vacuum tube work. OK for most solid state. I still like analog meters for checking transistor/diode front/back ratios. I have a Simpson 260 VOM and a HP-427 electronic voltmeter (think VTVM). It's been years since I used either.
A good quality DMM is hard to beat for tube work. I mainly use a Fluke 87V but recently purchased a Klein MM700 (https://www.amazon.com/Multimeter-Auto-Ranging-Klein-Tools-MM700/dp/B018CMKWSC/) just so I always have one meter in the house and one meter in the shop. The Klein is rugged and competes favorably with my Fluke and costs under $100.
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Sluckey you are right about 20k ohms / volts sensitivity meter. It is not a very good meter.
You Klein MM700 look could be better than mine.
We have to say, It is not only the price, we must know what we bought
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I also have a Klein CL3100 ( $90)
Is this the Klein CL3100 (https://www.amazon.com/Klein-Tools-CL3100-200A-Meter/dp/B003LHIB7I/) you have?
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I also have a Klein CL3100 ( $90)
Is this the Klein CL3100 (https://www.amazon.com/Klein-Tools-CL3100-200A-Meter/dp/B003LHIB7I/) you have?
Yes, I bought it for an ammeter clamp. It could read all voltage too, not so well ( it's slow ) like my Fluke
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"A good quality DMM is hard to beat for tube work. I mainly use a Fluke 87V but recently purchased a Klein MM700 (https://www.amazon.com/Multimeter-Auto-Ranging-Klein-Tools-MM700/dp/B018CMKWSC/) just so I always have one meter in the house and one meter in the shop. The Klein is rugged and competes favorably with my Fluke and costs under $100." The amount of work I do doesn't justify a Fluke. That MM700 looks like it might fit the bill. In reading their promotion (ad) they make it sound like it's made in the U.S. and that is a plus for me. Do you know if that is so or are they just saying it's an American Company? [color=rgb(86, 89, 89) !important]About Klein ToolsAs an American manufacturer of hand tools for more than 160 years, Klein Tools makes premium-quality, professional-grade tools that deliver performance, durability and precision. Our team continues to put six generations of expertise into each tool by using the highest quality materials and superior workmanship.
Klein Tools doesn't just make great products, we make great products that stand up to the demands of the professionals who use them every day Since 1857.
[/color]
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"Or it is because you may not know how to use it ?.
(Think) ending of Quigly down under :l2:
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"Or it is because you may not know how to use it ?.
(Think) ending of Quigly down under :l2:
Did you see the " ? "
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If the meter was made in USA you can bet that fact would be plastered all over the ad. And stamped on the meter too. No such markings on my meter. I suspect the meter is made in China but that fact is probably buried in the fine print.
This screwdriver was "Assembled in USA of US and imported components". Made in USA is very prominent on the ad and is also stamped on the black rubber part of the handle.
(https://m.media-amazon.com/images/I/51xlk4+8bcL._AC_SL1000_.jpg)
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Did you see the " ? " Yes, I understood it was a question, that was the answer .... Quigly said He didn't care for pistols not that He couldn't use one. I didn't take it as an affront nor meant one
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... I was down to one meter ... I found a harbor freight giveaway ...
... I am not really happy with the digital world of meters. ... I really liked my old Micronta. I have a desktop Simpson 266 but it's playing possum ...
... The amount of work I do doesn't justify a Fluke. ...
Buy Once, Cry Once.
I bought a Fluke 87III about 20 years ago. I've changed the battery 2 or 3 times, but it has otherwise been flawless. I'm uncertain about how tight the calibration is, but it seems plenty-close enough for me.
I've bought some other VTVMs since getting the Fluke, but due to curiosity and never because my meter wasn't working. I'd buy a used Fluke, Agilent, or Keysight DMM if I had to do it over. You can find plenty of them at pawn shops, because of people in the automotive & construction trades falling on hard times.
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....There's usually a battery inside (even on old VTVM meters if they do not get plugged into the wall). The "Ohm" setting could very well be a "Volt" measurement, but using the internal battery to supply volts/current through the resistance being tested....
Most VTVM (most were wall-plug) used a C-battery to force the Ohms function. It generally was not possible to rig a stable high-current supply for this, in those days. When VTVMs and even C-cells got old-hat, I did rig one with a LM317 fed from the heater line; not really a good use of time and dimes.
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OR......It could have been the 500ma fuse? :dontknow: I finally figured that out ....The Ideal is a pretty good meter after all. I just checked it a couple days ago ..... It's cement not glass ....ordered up 5 replacements ....