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General Electronic Part question

jtrouter

Well-Known Member
Jul 7, 2015
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Hello,
I long ago blew up my old trusty Micronta 22-220 fet Vom. What ever i did when i switch over to
the audio cont. checker it just has tone always no matter what i do.
Everything else works on it but i really want that feature back. I opened it up and found the part
that was destroyed inside. Its green and it looks like a disc cap? when i looked at the schematic
it calls it SA1 it also says that on the board where it was. Can anyone tell me what a "SA" is?
I have never seen that symbol before? And do they come in values? So i can replace it?
Thank you for reading.
 

Found the schematic. Gargle is your friend. But only if you call from time to time.

Looks to me as if it is a MOV. Can't find any mention on the net of that sort of component with that name. But a MOV will limit voltage across the probes from exceeding the MOV's breakdown rating.

Looks as if the max DC voltage scale is 300 Volts. Touching the probe to a voltage higher than the MOV's rating will cause the MOV to break down and become a short. Sometimes a MOV will protect a circuit from excess voltage only once.

73
 

Attachments

  • micronta_22-220_fet_muiltimeter_schematic.pdf
    2.1 MB · Views: 6
?Found the schematic. Gargle is your friend. But only if you call from time to time.

Looks to me as if it is a MOV. Can't find any mention on the net of that sort of component with that name. But a MOV will limit voltage across the probes from exceeding the MOV's breakdown rating.

Looks as if the max DC voltage scale is 300 Volts. Touching the probe to a voltage higher than the MOV's rating will cause the MOV to break down and become a short. Sometimes a MOV will protect a circuit from excess voltage only once.

73
I did think that it looked like a MOV but when i did a search of schmatic symbols i did not see any like that "SA" and the only MOV i have ever seen were blue. Anyways when i just looked up MOV symbol it is not the same as on the schematic.
I will go thru my parts bin to see if i have any. For a quick test would it be SAFE to just jump the location and see if it will work still? I blew it more than 5 years ago and I have never tested anything over 220vac with that meter but its possible i might have had it on a wrong scale?
This is the replacment i found on Amazon does this look like a safe replacment?

MOV-20D431K VARISTOR, 430V, 275VAC, 350VDC, 20MM DISC​

And a very large THANK yOU for responding!
 
Your “cap like” physical description also fits a surge protection disk type Varistor (MOV).
In general terms, SA-1(Surge Absorber, Type 1). Among others, LittleFuse is a popular brand that makes those. Color doesn't add any particular value that I know of.

Meanwhile, it also wouldn't hurt to check and see if all the associated resistors are within tolerance.
 
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Your “cap like” physical description also fits a surge protection disk type Varistor (MOV).
In general terms, SA-1(Surge Absorber, Type 1). Among others, LittleFuse is a popular brand that makes those. Color doesn't add any particular value that I know of.

Meanwhile, it also wouldn't hurt to check and see if all the associated resistors are within tolerance.
Sounds like a great idea, I will test them tomorrow. Thank you.
 

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