Micronta 22-220a Manual
I am looking for a service manual /and or schematic for this multimeter.Can anyone help?? Tektronix has over 60 years of experience designing Test and Measurement equipment. Learn about our industry-leading Test and Measurement tools.
Hello everyone, Please bear with me since I'm new to this site. I have a Micronta 22-220A multimeter that I bought in 1994. I'm wondering what is the correct procedure for setting zero on the ohms scale. When I set zero according to the user manual on the X10 setting then switch it to the X1 setting the needle moves to the left from zero to 1 ohm. When I set it at zero at the X1 position and select the X10 position the needle moves to the right the same amount. Switching from X10 to X1K (there is no 100 ohm position) only a negligible movement is visible.
No movement is noticable switched to X10K and X100K. Do I have to reset zero every time I use the lowest two settings? Or is there something wrong or something that I'm not getting? Thanks in advance for any help.
My e-mail is. The forum moderator, 7jp4-guy, gave you solid advice, and as for mine, go to Harbor Freight's website and key in multimeter, and you will find several for under five bucks.
You should always buy the cheapest multimeter you can find, because you know you can always toss it out if you accidentally fry it, and there is always time to upgrade later right? Food for thought- even one of the most expensive CAT III/IV safety rated DMM’s will be cheaper than the funeral, or even an emergency room visit today. All new digital multimeters can provide measurements. But when a company is selling a give away priced multimeter made with the most inexpensive components available, be rest assured it is provided with either bare minimal or no protection from overload. Perhaps fine for the car or battery operated transistor radios, but when you are playing with these meters inside tube equipment with higher voltage potentals, the risk to yourself and your level of trust in the multimeter becomes more substantial.Mark- My Current Projects.
The forum moderator, 7jp4-guy, gave you solid advice, and as for mine, go to Harbor Freight's website and key in multimeter, and you will find several for under five bucks. You should always buy the cheapest multimeter you can find, because you know you can always toss it out if you accidentally fry it, and there is always time to upgrade later right?
Food for thought- even one of the most expensive CAT III/IV safety rated DMM’s will be cheaper than the funeral, or even an emergency room visit today. All new digital multimeters can provide measurements. But when a company is selling a give away priced multimeter made with the most inexpensive components available, be rest assured it is provided with either bare minimal or no protection from overload. Perhaps fine for the car or battery operated transistor radios, but when you are playing with these meters inside tube equipment with higher voltage potentals, the risk to yourself and your level of trust in the multimeter becomes more substantial.Mark- My suggestion was simply to enlighten him on an inexpensive alternative to having to zero an analog meter, for general usage.
Had he said that he was going to be delving into high current tube equipment, the advice would have been different. And since you are involving yourself, perhaps you might want to advise him on the limitations of using his Micronta 22-220A multimeter in said equipment. He Who Dies With The Most Radios Wins//////////////////.
The 22-220A is a FET VOM and very nice. Digital is good but for a good one plan on spending $30-$40. There is a video on youtube going over all the different entry level DMM's. Here is the parts list: Here is schematics: 2/3 rds down is a link 'Down load the file, please click here!' Get a dialog box and save to desktop. It's a ZIP file. The free Un-ZIP program is available on the web if you don't already have it.
Radio shack list it for download of a manual but it's not avaiable, but some of the other meter manuals will be close: Here is the manual for the 22-211 (may be close enough) 2/3 rds down is a link 'Down load the file, please click here!' Get a dialog box and save to desktop. It's a ZIP file. The free Un-ZIP program is available on the web if you don't already have it.
The manual will tell you how to operate it. For Ohms you set the ohm range you want, touch the two probes together and ZERO it out. Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780. And since you are involving yourself, perhaps you might want to advise him on the limitations of using his Micronta 22-220A multimeter in said equipment.
FET-VOM's in general are often very sensitive regarding their inputs, thus I would advise to not use this type of meter to measure within tube related equipment under power as the meter would be easy to damage and it really offers very little in the form of high voltage protection. As this is an antique radio forum, I often presume (perhaps sometimes wrong) that tube type equipment is one of the intended applications of test equipment inquiries, and its good to know if you are picking or using a good tool for that type of work. I will post some pictures soon to show exactly why a Harbor Freight $3.00 DMM is NOT a good tool to be using within tube equipment under power- seriously.Mark- My Current Projects. And since you are involving yourself, perhaps you might want to advise him on the limitations of using his Micronta 22-220A multimeter in said equipment. FET-VOM's in general are often very sensitive regarding their inputs, thus I would advise to not use this type of meter to measure within tube related equipment under power as the meter would be easy to damage and it really offers very little in the form of high voltage protection. As this is an antique radio forum, I often presume (perhaps sometimes wrong) that tube type equipment is one of the intended applications of test equipment inquiries, and its good to know if you are picking or using a good tool for that type of work.
I will post some pictures soon to show exactly why a Harbor Freight $3.00 DMM is NOT a good tool to be using within tube equipment under power- seriously.Mark- I agree with Mark 100%. You can use this FET (Field Effect Transistor) VOM. However the trick working with a tube radio (with +100 volts AC and DC) is to make sure you select the proper scale before probing around. If you do that there is no problem. FET's do have limits and can be damaged but the 'front end' of the meter (user selected scales) protects it.
Most modern DMM's have protection, to where even if you screw up and measure high volts with OHMS selected, for example, it will not damage the unit. My DMM is auto ranging. That is ideal for me. When checking a tube radio you may check a low bias voltage then check a B+ voltage. With a manual meter you have to selected different scales.
Failure to do that MIGHT cause damage. A good meter should be made to take some abuse with out failure. The design of your FET VOM can be evaluated from the schematics. I am sure there are scenarios where you can damage it. Again some care can avoid that. An auto ranging DMM to me is the way to go. With that said there is nothing wrong with using a FET VOM, if you use a little care.
Clearly if you are probing around you need to select the highest AC or DC volts first then work you way down. Not sure if measuring DC with AC selected or vice verse is going to cause damage. It might, might not. As far as Harbor Freight, I just got my $3.99 DMM replaced (I have about 6 DMM's, VOM's, VTVM's). It stopped measuring Ohms, but measured volts AC/DC just fine (accurate).
Out of 90 day warranty, they exchanged it. It works perfect and is very accurate on AC/DC volts, ohms and amps (I checked it against a Fluke). So far I got my $3.99's worth out of it. Harbor Freight gives out coupons for these DMM's, FREE! They have a very good IC chip in them, which is what most DMM's are, one big square IC with lots of connections. The Harbor Freight DMM is NOT auto ranging and likely has little protection, so you could hurt it.
No doubt I checked high volts in Ohms and may have damaged it? So I use this just to check DC batteries and ohms on my 'battery bench'. They are nice to have in the car, boat, garage just for general use. At $3.99 you can toss it, if they go bad. However if you have one DMM get a good one, at least $30. See the videos below.
This thread was simple how do you calibrate the unit for volts or ohms. You did not ask about getting a DMM. However since we went that way DMM's are faster, easer to read and use (auto-range). Here is a video on some cheap DMM's. You can pick up a nice DMM mail-order from an internet store or eBay.
Here is a video where a gent from Australia tests a bunch of inexpensive DMM's in detail. In general $30-$50 will get you a VERY nice DMM with capacitor checking. The next level is the under $100 DMM's which doesn't get you a lot more. Then the Fluke level of quality, $200 to $500 range is the best you can get in durability, safety and accuracy.
For hobby work a Fluke may be overkill, however you can pick up a good clean used Fluke for about $100. If you have an hour or two to kill, want to learn all about DMM's, here are some videos: EEVblog #91 - $50 Multimeter Shootout - Extech EX330, Amprobe AM220, Elenco, Vichy VC99, GS Pro-50 (skip to end for conclusions, but it's interesting all the criteria he uses to evaluate the meters) EEVblog #75 - Digital Multimeter Buying Guide for Beginners EEVblog #6 - Part 2 of 2 - Why cheap multimeters suck Another shoot out with a little more expensive DMM's. If you want to skip to end, you can hear his conclusion. EEVblog #99 - $100 Multimeter Shootout - Extech Amprobe BK Precision Ideal UEi Uni-T PART 1of2 Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780.
I have one of these meters. (procedure deleted as someone else said it better than I did) I like this meter alot and mine still gets used occasionally. I don't think anyone is trying to pull your leg. All of us have had different experiences, opinions and preferences. So when you ask a question here we are going to recommend what has worked well for us.
My best advice if you are going to use a cheapie harbor frieght or similar meter for radio work, is not to hang on to it while your making a measurement especially with high voltages or current. That way the oops isn't going to be in your hand. I blew up one of those $20 deluxe? Harbor frieght meters measuring current on a motor. The motor stalled and I had a nice smoke show for about 30 seconds. I have one of these meters.
Micronta Multimeter User Manual
(procedure deleted as someone else said it better than I did) I like this meter alot and mine still gets used occasionally. I don't think anyone is trying to pull your leg. All of us have had different experiences, opinions and preferences. So when you ask a question here we are going to recommend what has worked well for us. My best advice if you are going to use a cheaper harbor freight or similar meter for radio work, is not to hang on to it while your making a measurement especially with high voltages or current.
That way the oops isn't going to be in your hand. I blew up one of those $20 deluxe? Harbor freight meters measuring current on a motor. The motor stalled and I had a nice smoke show for about 30 seconds.
The question he asked was a simple one regarding operation of the FET VOM. He got a some what sarcastic reply, that was not directed at answering the question. I would say if you are routinely working on more than house hold line voltage, don't use any meter that is not CAT III rated (which can handle huge transient surges). The harbor freight is NOT CAT III certified (it says CAT II). The probes on the harbor freight are tiny, leads short and NOT for working on high voltage. Why buy new probes when you can get a $40 DMM with decent probes. As far as curent most of us are dealing with an amp or so.
The harbor freight can handle up to 10 DC amps; it has a big fat shunt in there. It is also overloaded protected, fused. If 10KVA went through there it would smoke. CAT III is suppose to not explode with surges of 10,000 to 17,000 amps! Here is a good article on DMM categories.
I have several harbor freight cheap DMM's with my flukes and others. They are just back ups, and I would never recommend it as our only DMM. Here are three of the BEST cheap DMM's in order (shop around for discounts). These are all Cat III rated I recall The Extech EX330: $60 The Amprobe AM220: $43 The Elenco M-2625: $40 (Also Jaycar Digitech QM1535) If you want to see DMM's exploding on purpose (over 7 times the rating): EEVblog #84 - High Energy Multimeter Destruction For $3.99 on sale this is a great deal but not an every day DMM.
Note: surface mount and fuse protection. More 30 VAC or 60 VDC extreme caution. Obviously 110 VAC can be deadly but the meter should not explode ever. Even the Harbor Freight has input protection, but if you anticipate big transient surges then get a real professional DMM. Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780. I had taken this thread off the topic, and I apologize for that.
I did however continue my discoveries on this new topic I started on the subject: I don't believe any of the surface mounted components within the HF cheapie DMM are for protection, (possibly a couple low wattage SMT input resistors, but no PTC's or varistors.) and I have no reason what so ever that it could stand up to the IEC CAT II safety rating, which isn't even printed on the meter face with the right nomenclature. I'll agree the FET VOM's are safe as long as you start off in the highest range when measuring unknown voltages and make sure you are not in ohms scales. I have had a lot of Radio Shack braded VOM's come across my eyes with the RX1 range resistor burned in half when power was accidentally applied in the ohms scales.Mark- My Current Projects. I don't believe any of the surface mounted components within the HF cheapie DMM are for protection, (possibly a couple low wattage SMT input resistors, but no PTC's or varistors.) -Mark- It does have one fuse, an 'overload' fuse per the manual and I see it. Other than that you are probably right, no MOV's or TVS's (varistors).
I see no tell tale MOV/TVS looking devices. Which tend be barrel shape.
I think the Ohms section is very vulnerable, meaning put some higher volts in ohm position you cook something, IC or supporting circuit (resistor, capacitor, diode). The good part is the ohms seems isolated. When it stopped working for me (just showed -1 or 1 for out of range) all the other functions worked. My better DMM's have more than one fuse. And on occasion I have blown them. Replacement always restores full operation. The HF DMM is CAT II rated, which is for single phase and limited surges.
Free Micronta Manuals
If you try and run 1000 amps through it, you'll blow it up. If the 'overload' fuse does not save the day, I suspect capacitors and resistors will literally blow up. CAT III DMM's have HEAVY cases with interlocking sides so any out gassing will not cause the DMM to blow out, containing the discharge inside the case. This cheap DMM is just snapped together with two wood screws in plastic holding it down. Good DMM's have inserts and machine screws. Again I use mine to check my 1.5 and 9 volt rechargeable batteries and check resistors, organize loose parts in the junk box. Occasionally check line voltage with it.
I have used the battery, diode and transistor functions. They work fine. To work on tube radios I use an auto range DMM or VTVM. Tube: AM/FM Zeniths, RCA, TrueTone table tops; Transistor: Kaito KA1103, TenTec RX320D, Pioneer SX780.
Country: Manufacturer / Brand: Year: 1988 Category: Service- or Lab Equipment Semiconductors (the count is only for transistors) 5: Wave bands - without Details Power type and voltage Dry Batteries / 9 & 1.5 Volt Loudspeaker -No sound reproduction output. Power out from Radiomuseum.org Model: Micronta FET Analog Multitester Cat No. 22-220 - Radio Shack Tandy, Realistic; Material Moulded (Bakelite or Plastics) Shape Very small Portable or Pocket-Set (Handheld).