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bettablue
March 25th, 2012, 07:04 PM
:stupid: If I'm in the wrong forum, sorry. Please move it to the correct forum if necessary.

O, I'm lost. I bought this Radio Shack Micronta Multimeter, part #22-205 through E-Bay a little while ago. I only paid $9.99 for it including shipping, so I'm not out a lot of money. The seller reported that the meter won't read anything on the 20K-Ohm resistance scale. I initially thought it had a blown resistor or diode. So, I tested all of the components, resistors, diodes, capacitors; everything. Well, as it turns out, there's absolutely nothing wrong that a new set of batteries won't fix. The meter takes a single "C" cell plus another battery. The thing is... I can't tell what that bettery is or what voltage the meter wants. The battery seems to be an integral part of the failsafe cirtuit; which explains why the one particular resistance scale won't work. It is the most susceptable to blowing by doing something stupid like applying having the meter set to measure a voltage instead of resistance.

Inside, the battery compartments are extremely clean. This meter doesn't appear to have been used much at all. Looking at the battery compartments though, the only marking that can be seen are arrows indicating polarity. I was initially thinking of one of theos 9 volt camera battereis, but I think those might be too small. It's also not a stack of button cells either. The only thing holding the batteries in place are the battery clips on the ends of their respective compartments. There is some marking on the outside of the battery compartment in white ink, but I don't think it means anything.

I need a manual... Pure and simple. Plus if I can get a schematic, that would be awesome. I've been looking for a manual for this thing, but it's so old that finding a manual, or other documtation is proving to be a challenge. So I though I'd ask here.

Does anyone here have a manual and possibly even a schematic for this little beasty? Anything at all will help though. (Well, almost anything)

Till then, I have to use this el-cheapo digital thing my wife bought me. (But that's another story) :blush:

I'm attaching a couple of pics to show the size of the battery compartment. Right next to it is the "C" cell in it's compartment. Hope these help.

Thanks again.

Chuck(G)
March 25th, 2012, 07:59 PM
I'm going tto guess that it's a L1022/10A sized battery and is 9V. That, at least seems to square with the other Micronta multimeters that I've been able to find. And yes, it's only for the high resistance range, according to other manuals. It's 22.2mm tall.

bettablue
March 25th, 2012, 08:39 PM
I'm going tto guess that it's a L1022/10A sized battery and is 9V. That, at least seems to square with the other Micronta multimeters that I've been able to find. And yes, it's only for the high resistance range, according to other manuals. It's 22.2mm tall.

Is there anything you don't know? I'm having the wife look at Wally World when she gets off work tonight. Don't worry, she's already going there for our weekly shopping any way. Now, all I need is a manual for the thing. Sheesh, you'd think they held some military secrets or something.

So, if Wally World doesn't have it, do you think Radio Shack would? I ask because they have changed so much since they were sold by Tandy, and you just never know what they have any more.

Thanks again Chuck

Cheers.

Chuck(G)
March 25th, 2012, 09:20 PM
These aren't as common as they used to be (you could find them in some garage door remotes, for example).

Batteries Plus
2370 E Serene Ave
Las Vegas, NV 89123

PHONE NUMBER:
702.221.9315

STORE HOURS:
Mon—Thurs:8:30-8:00
Fri : 8:30-8:00
Sat: 9:00-6:00
Sun: 10:00-5:00

would almost certainly have it.

Ole Juul
March 26th, 2012, 12:08 AM
This all rings a bell, but I can't remember where my Micronta Multimeter is so am unable to check. My vague memory is that its a 22.5v battery like the ones for flashes. They were pretty common.

angel_grig
March 26th, 2012, 12:30 AM
Your multimeter is a 1975 model and you can see it here:

8321

from the Radio Shack catalogs site here:
http://www.radioshackcatalogs.com/html/1975/h113.html

Also on the same catalog look at the batteries sold by Radio Shack back then here:
http://www.radioshackcatalogs.com/html/1975/h062.html

Maybe the U15 type (22.5v like Ole Juul said?)
http://www.ebay.com/itm/2-15F20-22-5V-Carbon-Zinc-Battery-412-U15-VS084-MN122-/220781419843#ht_1057wt_810

Chuck(G)
March 26th, 2012, 08:22 AM
Given the age of the meter, that might be closer. Also, consider this discussion about batteries for a Simpson 260 (http://www.eham.net/ehamforum/smf/index.php?action=printpage;topic=72877.0).

Bottom line is that it may be a toughie to locate.

MikeS
March 26th, 2012, 09:08 AM
FWIW, my analogue VOMs use 15V and 22.5V batteries for the high Ohm range; doubt you'll find anything at WallyWorld ;-)

If you've got a variable resistor of some kind, just snap two or three 9V batteries in series and adjust the voltage until the high Ohms scale looks OK and that'll tell you what you need.

Pity you don't have the old one; the antique radio folks stuff the old batteries with new innards all the time.

8322

bettablue
March 29th, 2012, 01:38 PM
Unfortunately, I don't have the things you've mentioned here, but I was able to confirm the battery. I also found something I though was kind of funny. The Micronta 22-205 multimeter is almost identical to the Micronta 22-207. I'm still unable to find anything on the web that will help me, but the battery store has bothe of these listed as taking the same 22.5 volt battery. I just wish there was somewhere to get a schematic an use manual for this meter. It is a very nice meter, and is in great shape. My wife is getting the battery for it tomorrow.

Along the same line, I'm getting a Simpson 260 series 6M. I already got one through E-Bay, but the R x 100 scale would not zero, so I returned it and getting a replacement. The one I'm getting in exchenge is supposedly great condition with all of the printing very clean and sharpand the bakelite case is in perfect condition.

After seeing other analog multimeters on E-Bay, I really have to agree... They really don't make them like they used to. The old ones have a much better look and solid feel you just don't get today.




FWIW, my analogue VOMs use 15V and 22.5V batteries for the high Ohm range; doubt you'll find anything at WallyWorld ;-)

If you've got a variable resistor of some kind, just snap two or three 9V batteries in series and adjust the voltage until the high Ohms scale looks OK and that'll tell you what you need.

Pity you don't have the old one; the antique radio folks stuff the old batteries with new innards all the time.

8322

Chuck(G)
March 29th, 2012, 03:59 PM
After seeing other analog multimeters on E-Bay, I really have to agree... They really don't make them like they used to. The old ones have a much better look and solid feel you just don't get today.

On the other hand, for less than $30, you can get a 3.5 digit digital one that also measures capacitance, and temperature and has an audible continuity tester. You also won't cry too hard if you drop it into the bathtub.

I can recall doing millivolt measurements in my salad days using an L&N portable potentiometer. Had a galvanometer, slidewire, Weston standard cell and a dry cell. You had a thermocouple that needed to be measured, so you took out your handy-dandy pocket thermometer, got the cold-junction ambient temperature and looked it up in a booklet for the offset voltage for the given 'couple type (e.g. Chromel-Alumel, Iron-Constantan, Platinum-Rhodium, etc.), calibrated the primary source (dry cell) against the standard cell, hooked everything up, balanced the galvo, and translated your reading in the book back to a temperature--and then corrected the controller that it was attached to. Repeat as needed on the same instrument, pack everything up and move on to the next instrument. Repeat perhaps 100 times, moving down the line (in the pic below, note the empty booklet clip in the lid):

http://www.photocamera.com/pictures/0304/Picture%20018.jpg

So, I really don't have much fondness for analog meters, myself. They are useful, however for seeing slow trends.

One issue with the old meters is that the high voltage used on the high resistance range can damage delicate solid-state components.

bettablue
March 29th, 2012, 04:44 PM
Maybe so Chuck, but at the same time, the quality of some of those 30 dollar meters is so bad, they're worse than useless. C'mon, I know my home voltage is nowhere near 135 Volts AC. That difference can be real dangerous to someone relying on an accurate reading. If you go digital, spend some money and buy a Fluke. I personally like an analog meter too for testing circuits for continuity. While some of the newer meters have an audio feedback, I personaly like an analog meter for that because it's easier to see the needle move out of the corner of my eye than on an LCD display.

I do agree that everyone has their own preference. Mine just happens to be for a good analog.

Chuck(G)
March 29th, 2012, 05:28 PM
Maybe so Chuck, but at the same time, the quality of some of those 30 dollar meters is so bad, they're worse than useless. C'mon, I know my home voltage is nowhere near 135 Volts AC..

Well, the first thing is to know your metrology. Line voltage is nominally 120 V RMS. A moving-coil meter tends (by dint of its mechanical workings) tends to measure the average voltage through it, but that isn't necessarily RMS. (Recall the scales on your old 260 when it comes to RMS vs. PP). Depending upon the waveform, moving-coil meters can be just as inaccurate as simple digital meters.

For a bit of the theory see this tutorial (http://www.allaboutcircuits.com/vol_2/chpt_1/3.html)

True RMS AC voltmeters tend to be quite expensive (e.g. HP 3400 series).

glitch
March 29th, 2012, 06:37 PM
On a note concerning the original post, my Simpson 160 (the hand-size version of the 260) uses a 22.5 V battery as well. Eveready still makes them. I picked up two of them for my toolkit around a year and a half ago, when I was traveling to on-site installs pretty much every other week. Search Amazon for "22.5 eveready", there's a seller who always has them in stock for around $10. Also, as long as you remember to leave your meter in a non-resistance mode, the battery will last for many years.

Also, if you're in the market for a Simpson 260, find out which models used just a 9V and a D cell. Much easier to find 9V cells!

Chuck(G)
March 29th, 2012, 06:45 PM
I still have my VTVM, but have long since replaced the battery with a simple line-operated voltage reference. Much easier if you don't have to worry about the darned thing leaking.

bettablue
March 29th, 2012, 08:32 PM
On a note concerning the original post, my Simpson 160 (the hand-size version of the 260) uses a 22.5 V battery as well. Eveready still makes them. I picked up two of them for my toolkit around a year and a half ago, when I was traveling to on-site installs pretty much every other week. Search Amazon for "22.5 eveready", there's a seller who always has them in stock for around $10. Also, as long as you remember to leave your meter in a non-resistance mode, the battery will last for many years.

Also, if you're in the market for a Simpson 260, find out which models used just a 9V and a D cell. Much easier to find 9V cells!

I hope my previous reply didn't come off as rude... That certainly was not my intention.

Glitch; this is all good advice, and well heeded. Thanks for bringing us all back on track. The Simpson meter I bought does use a standard 9 volt battery along with a "D" cell. All other arguments and discussions aside, what really matters is what you're comfortable with. I personally believe everyone should have both an analog and a digital multimeter in their tool chest. I do, and find that each is better in some things than others. Take for example, testing AC voltage on a CD circuit. Most multimeters can't handle that, but the Simpson was designed with that being one of it's key features.

One of the main features of the old analog meters is in their simplicity. They have fewer parts for things to go wrong with. That in my mind is always a good thing.

For the record, Ole Juul was correct in his assumption of which battery to look at for my VOM. Even though it's going to cost about $10.00, it's still a good value. Given normal use and proper care, these batteries should last several years. That much I do remember.

Thanks again to all of you for your input. I like this discussion and find it invaluable. Too bad we could have this discussion in person. I bet it would get pretty heated at times. :-)

glitch
March 30th, 2012, 04:13 AM
Glitch; this is all good advice, and well heeded. Thanks for bringing us all back on track. The Simpson meter I bought does use a standard 9 volt battery along with a "D" cell. All other arguments and discussions aside, what really matters is what you're comfortable with. I personally believe everyone should have both an analog and a digital multimeter in their tool chest. I do, and find that each is better in some things than others. Take for example, testing AC voltage on a CD circuit. Most multimeters can't handle that, but the Simpson was designed with that being one of it's key features.

Yup, I agree. I've got both my Simpson 260 and a 3.5 digit Fluke bench meter on my workbench. I tend to use the Simpson meter for quick measurements and the Fluke for fine-tuning things like voltage references or checking precision resistors. I also find it's usually easier to find intermittent connections with an analog meter, since my Fluke meter is pretty old and doesn't update its display quick enough for some intermittent things.

bettablue
March 31st, 2012, 02:18 PM
One issue with the old meters is that the high voltage used on the high resistance range can damage delicate solid-state components.

That is something I hadn't thought about. Guess I've been pretty lucky to not have blown anything out while testing.

bettablue
April 4th, 2012, 06:05 PM
It's taken a while to narrow it down, but the folks at batteries plus were finally able to get the correct battery fot his meter. It wasn't the square 22.5 volt battery we thought it was. The U-13 was still way too big. Instead, it is a much smaller round battery. The 22.5 volt battery was $13.95 and the one I eventually bought, and Eveready 504 15 volt was only $9.99. The way I use this meter, it will probably last me a few years. So it's a good buy investment.

Not only will the 15 volt battery only allow the Rx100,000 scale to be used, but the it powers the protection circuitry like the higher voltage battereis do in the Simpson meters. So now my old Radio Shack meter is back to normal and all of the ranges work again. That's the important thing.

I am now waiting for TWO Simpson 260 multimeters to arrive. One is a model 260 series 6M which is in perfect working and cosmetic condition that I paid almost $60.00 for, and the other a model 260 series 5P that needs a "AA" battery terminal replacement which was a freebie. A member in another forum is sending it to me so I can reqair it an do what I will after that. I was thinking that after I repair the 5P, I could sell it to make some money back. I'll see if I get any offers. Other than the missing terminal, there is supposedly nothing wrong with it. I'll leave that judgement for when I actually have it in my hands to do an eval. I may or may not need more than a battery terminal. But if that's all, I'll try making my own out of zinked spring wire. I've done that before with excellent results.