EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: necessaryevil on February 18, 2015, 02:16:48 pm
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Hello,
I have done a quick teardown on an old Hioki Model 3015 Analog Multimeter.
O yeah, one 'by the way' question. I guess it does not work appropriately, however, I have to find out how the scale works. Anyone knows what I should read if I plug it into the 230V mains?
No more questions, I just want to show you what's inside a multimeter. You are encouraged to give your opinion about the construction.
Pictures:
Image 1:
Front view. On the background: dust from my pencil eraser :P
Image 2:
Back side removed
Image 3:
The messy inside. The fuses are rated 250v. The meters servo (or whatever it's called which drives the needle) is located below the white notch (do you call it that in english?) in the center, just above the pcb. The threaded screw is inserted in the same notch/recess/cutout or whatever which encloses the servo.
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Another two photo's
Image 4:
Charring on the center left of the back side of the enclosure! Clearly someting happened!
Image 5:
PCB backside. I guess the contacts for the range switch are decent quality.
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The last two.. I hope it is allowed to put pictures in the reply to get a little more than 2MB for attachments.
Image 6 and 7:
The range switch below the pcb with and without the rotary contacts.
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Oh yes there happened a bbq inside the multimeter . look at the black part next to the rail in the middle of the top . If you replace it then it maybe work again . It s a nice little cute multimeter . Thank you for the teardown pictures
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Why does it have 2 batteries? AA & 9v.
Is the temp internal?
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Probably the Rx1 resistor burned - or possibly the milliamp shunt resistor.
I see it does AC current. Uncommon for an otherwise ordinary low-end analog model. I have a small RCA cheapie that looks almost identical, especially those cheap input jacks. Doesn't do AC current though.
Surprisingly it may be the most accurate analog I own. Dead-on on every range, every function.
Easily on a par accuracy-wise with my Bach-Simpson 635 and my AVO 8 mk5, but such horribly cheap physical construction!
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Thank you for your replies. Maybe I'll try to fix it - it does not have much components, but first I have to find out how to read the meter. It says 20kOhm/V dc; 9kOhm/V AC and 9kOhm/DC 300VUP.
The construction looks a bit weird to me. Well I don't know that much about multimeters, especially not about older analog types; but to me it looks like an attempt to a quality multimeter with some design quirks. Well, a design quirk, it's mostly the spaghetti style wiring that I think is weird.
I don't know why it has both a AA battery and a 9V battery.
On the Hioki site it says that they discontinued this model in 1990.
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Why does it have 2 batteries? AA & 9v.
For the different resistance ranges, 9V is for the megaohm range.