Author Topic: TY720, KEW 1062, handheld multimeter, Inside High resolution images  (Read 1188 times)

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Offline Fungus

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #25 on: April 24, 2018, 06:59:06 pm »
Thinking to do the same for Hioki DT4282.

Go for it!
 

Offline joeqsmith

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #26 on: April 24, 2018, 08:55:30 pm »
First, thanks again for taking the time to post these.   My first impression was, wow they have a nice shield on both sides of the meter.  Gossen could learn from them.   Then I thought the meter reminds me of that Keysight meter I ran with all the ICs on it.   

It looks like they have the basic resistor, PTC then to the GDT with the two GDTs common in the center.   I can't tell if that center axial part ties to the common point which wouldn't make much sense.  I can't see the return path.  If the board is still out of the case, maybe hold it in front of a light so we can see the inner layers more easily.   

I have not found anything on the tubes they use but I'm guessing the 202 would be a 2KV part.   It's difficult to say how it would hold up.   

There appears to be some plastic from the case on the board. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #27 on: April 24, 2018, 09:07:58 pm »
Just finished watching the video.  Did you by chance take any pictures of the wiper contacts?   

At 6:40,  I thought with the two traces routing to the jacks, they were maybe detecting the leads being wrongly inserted which would need the split connectors.   Maybe a design prior to adding the shutter. 
How electrically robust is your meter?? http://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online coromonadalix

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #28 on: April 25, 2018, 06:42:43 am »
I cant understand why they did not use an dedicated dmm front end chip ???  tons of chipe here, the battery life must be ordinary ??
and the board is not cleaned after soldering  outch   :palm:
 

Offline fanOfeeDIY

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #29 on: April 30, 2018, 10:20:41 pm »
Just finished watching the video.  Did you by chance take any pictures of the wiper contacts?   

Took pictures.
Uploading the wiper contacts.
 

Offline fanOfeeDIY

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #30 on: April 30, 2018, 10:23:46 pm »
It looks like they have the basic resistor, PTC then to the GDT with the two GDTs common in the center.   I can't tell if that center axial part ties to the common point which wouldn't make much sense.  I can't see the return path.  If the board is still out of the case, maybe hold it in front of a light so we can see the inner layers more easily.   

I tried one with the light from the back.
 

Offline fanOfeeDIY

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #31 on: April 30, 2018, 10:34:04 pm »
My first impression when I open the case was the same as others.

The flux residues are left on the PCB.

My knowledge is that the best insulating material is the air,
and I worried that the flux would led arching when the transient voltage/current comes in.

The DMM itself looks at least six years old by observing the case and contacts,
the color of flux is still clear and have not changes to yellow which is normally one of the cause of corrosion.

 

Offline fanOfeeDIY

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #32 on: April 30, 2018, 11:42:29 pm »
There appears to be some plastic from the case on the board.

Thanks! :)

I removed it. It was the rubber from the surface of outer of the back case.

There are some peeling on the rubber surface of the corner of the case by probably the drops in the past,
and I must have put them inside when I open the case.

I looked around the case and there were no way that the peeling could go inside the case other than myself. :)

It could have changed the transient test too.
 

Offline joseph nicholas

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #33 on: May 01, 2018, 12:28:06 am »
It kind of looks like the company is reinventing the wheel with this meter, look at how they are doing measurements an calculations.  It sure is novel.
 

Offline fanOfeeDIY

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #34 on: May 01, 2018, 08:43:03 pm »
One of the reason I could think of why they have not used any of the DMM chipset could be that
one of the selling point of the TY720/KEW1062 is that it is able to calibrate by any user who
has references.

It show the User Calibration Function from page 107 to 111.
https://cdn.tmi.yokogawa.com/IMTY720-E.pdf#%5B%7B%22num%22%3A112%2C%22gen%22%3A0%7D%2C%7B%22name%22%3A%22Fit%22%7D%5D
 

Online coromonadalix

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Re: TY720, KEW 1062, handheld multimeter, Inside High resolution images
« Reply #35 on: May 03, 2018, 12:54:59 pm »
oh ho   nice of them to show us how to calibrate it ...  picked points here :)
 


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