Analog Multi-meter question,

[Big Wave D]

I have a nice old Micronta (Radio Shack) made analog multimeter. I needed to press it back into service for its 10amp, DC capability a few days ago. I was trying to track down some parasitic battery drainage on a vehicle.

It worked fine two days ago. Today I tried to use it and when I turned it on, it goes to full left deflection. In the On position, the Ohm and Zero adjustment knobs do nothing. Changing the dial between any of the settings does nothing either. If I turn the On knob to battery test, it does exactly as it should. It goes to the right to indicate battery strength.

I've checked the batteries and fuses and all are fine.

I'm kinda stumped. For it to have worked fine just a few days ago, and now this full deflection to the left today I'm experiencing. Yes, it could have just croaked today, but I'm thinking it is something I'm missing.

Any thoughts?

All ideas are greatly appreciated

 

[Ken]

I would check for the position switch the meter is being driven to the left by voltage so maybe a corroded wafer contact. or wire became loose. The bat.check is just a single switch to resistor to meter.
I have a stack of the little analog multi-meters. all one problem or another and unable to locate parts. Shipping prices excede the cost of new.
ken

 

[Big Wave D]

Hey Ken,

Thanks for the tips, I'll look and see if they lead to a "cure".

Yes, I fear that we live in the "Pitch Age". It kind of makes me sad that things are made SO cheaply that they have no intrinsic value to repair them. It's made a whole occupation almost extinct. Unless something costs almost $_______ or more(fill in your personal threshold), it's pitch it in the garbage and buy new.

Just a side question for curiosity sake, but what is YOUR(this question is open to anyone) pitch/repair dollar amount? $100, 350, 700, 1000, higher?????????

 

[Ken]

B.W.D. This depends on the personal value of what is being replaced. A multi-meter costing $9.99 Cannot purchase parts with out a mail order. I usually toss in the to be repaired later box. Have several of these. My digital cost around a $100 Would spend some time on looking for the problem.
When the dual trace scope went bad. the repair cost was more than another unit on e-bay. so now have almost total parts replacement for this tool.
My tractor when book keeper said costing $50. per hour of use for repairs. Put up for sale and purchased new tractor.
As said earlier depends on personal value what you have.
ken

 

[Big Wave D]

Ken,

I appreciate your response.

It seems like a person's age has a lot to do with how this question might be answered.

I posted this question to the main Parts/Repairs forum board. I'm kind of anxious to see what kind of a response this question gets.

Spread the word. The more input the merrier, I say.

 

[cityfarma]

I work on a percentage of the value of the faulty device taking into account the age.

Eg, a 10 year old TV is worth nothing then replace unless free repair. A 2 year old plasma worth $1000 and repair of $500 would be questionable. A 2 year old plasma worth $4000 and repair $1000 would be a repair. A repair of >50% of the value is probably a write off as a new device would also come with a warranty.

Cityfarma

 

[Treemonkey1000]

Are you sure the battery hasn't been put back in backwards on that thing? You sound familiar enough with the stuff so don't get offended. Depending on the Micronta a lot of them didn't have transistors in them which would drive the needle to the peg. You might just look to see if a piece of junk hasn't landed in there and shorted out some contacts. And last but not least those meters can develop poor solder connections which can do the same thing. Take a magnifier out and look for that unless you have really good eyes.
Another thought is make sure the Zero adjust pot for the Ohms hasn't opened up or something.
I work in an Calibration lab where we test electronic equipment for accuracy. I have been around those items a time or two.
My toss it factor is getting easier to do as I like to fix what I can. But I have a lot going and little space in my house so I tend to "donate" more now to the give away pile.

 

[bjr]

I've studied the new Z-drive lawn mowers and they appear to mostly use the Hydro-gear pump/motor drives. The Husquvarna dealer salesman said "Yeah there expensive to replace" as there's no rebuilding them and not supposed to ever add/check oil, "They never break Down". The drives are almost 3/4 the cost of a new machine. Just have throw away a $3000 machine and get new when it impossable happens. I'm gonna have to stick with my old mechanical drive Dixon, even if it's a bear to adjust all the components, Chain; bearings and sprockets belts are available at local bearing supply store and Agri-Supply has the blades. bjr

 

[Big Wave D]

Thanks to all who have posted helpful ideas of things to look at or for.

Just for kicks, I tried turning it on today and it "seemed" to work fine. I was using it to see if a Throttle Position Sensor was working or not.

The reason that I say "seemed" to be working okay was that when I was measuring battery voltage of said car's battery, it read consistently 1 volt lower than my little digital multi-meter.

I think I have the instructions still, but maybe what I need is a refresher course in setting up my Analog Multi-meter, Analog Multi-meter 101.

Here's a picture of it:

1) Under the white lettering "MICRONTA", what is this little slot screw used to adjust? (sorry, hard to see it in photo)

2) What is the proper usage of the Ohm's and Zero adjustment knobs?

Appreciate the help from anyone who takes the time to type all this out.

Thank you

 

[Treemonkey1000]

Thanks to all who have posted helpful ideas of things to look at or for.

Just for kicks, I tried turning it on today and it "seemed" to work fine. I was using it to see if a Throttle Position Sensor was working or not.

The reason that I say "seemed" to be working okay was that when I was measuring battery voltage of said car's battery, it read consistently 1 volt lower than my little digital multi-meter.

I think I have the instructions still, but maybe what I need is a refresher course in setting up my Analog Multi-meter, Analog Multi-meter 101.

Here's a picture of it:

1) Under the white lettering "MICRONTA", what is this little slot screw used to adjust? (sorry, hard to see it in photo)

2) What is the proper usage of the Ohm's and Zero adjustment knobs?

Appreciate the help from anyone who takes the time to type all this out.

Thank you

Analog meters are subject to errors from tipping if the movement is worn out a bit. Then reading errors from parallax errors (when you are looking at the needle from the side instead of from above) And some of them aren't very accurate to begin with. Your DVM could be off as well. Typically though the DVM will give you more accurate readings.
For the ohms mode you want to short the test leads together on the lowest range that you will be measuring. Then adjust the zero pot for 0 Ohms on the meter. As you change ranges you will probably have to rezero it for the most accurate readings.
Be careful measuring voltages of course like being on DC Volts for DC readings and AC Volts for AC. Some meters won't tolerate being hit too hard with high voltages on low ranges.
One thing you might check is to see if the needle moves back and forth smoothly? If the spring is weak or damaged or the pivots are worn the needle will not move smoothly. That can give you reading errors.