Products > Test Equipment
UNI-T UT61E Multimeter teardown photos.
joeqsmith:
Hey, I remember your other thread and was hoping you would have tried them out by now. I'm in no rush so take your time and post your results on the capacitance. Hard to believe it would be a problem as you zero it out anyway.
--- Quote from: MosherIV on September 01, 2016, 08:30:25 am ---Hi
--- Quote ---So, what I would like to do if modify this meter with the MOVs people are recommending, or use the parts that are available in the one being supplied to Germany. I will then retest it to failure and see if there are any improvements.
--- End quote ---
Look at this thread
https://www.eevblog.com/forum/testgear/varistormov-for-ut61e/
I have just got these
http://cpc.farnell.com/epcos/b72210s0381k101/varistor-40-0j-385vac/dp/RE03689
to fit in mine. Have not fitted them yet, I want to check the capacitance measurement before and after - I will only have access to a LCR bridge at the weekend to check the 1% caps, that I just bought, against the meter readings.
These
http://cpc.farnell.com/epcos/b72214s0321k101/varistor-84-0j-320vac/dp/RE03698
Will give you a lower clamp voltage but not give you the full 1000V DC spec
--- End quote ---
exxocet:
Hey guys,
I've got my UT61E back in 2010, way before it became the star of the affordable DMM show. :D Gotta be one of the first PCB layouts, there were no EU versions back then. Input protection is really basic, no safe-cut board on the PTC, no resistor area shielding, but hey, it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do. It served me like a hero and it still works damn well, but... what's that bridge on capcitors C9a and C9b? Is this a soldering fault or it's the default design on this early PCB version?
Maybe someone with a similar PCB would help with a picture of his own layout. Thank you.
joeqsmith:
--- Quote from: exxocet on October 05, 2016, 09:16:28 am ---Hey guys,
I've got my UT61E back in 2010, way before it became the star of the affordable DMM show. :D Gotta be one of the first PCB layouts, there were no EU versions back then. Input protection is really basic, no safe-cut board on the PTC, no resistor area shielding, but hey, it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do. It served me like a hero and it still works damn well, but... what's that bridge on capcitors C9a and C9b? Is this a soldering fault or it's the default design on this early PCB version?
Maybe someone with a similar PCB would help with a picture of his own layout. Thank you.
--- End quote ---
I would wager I could kill a brand new UT61E without anything more than the dry winter air, the carpet in my office, my metal desk and my hands. Sounds real industrial. :-DD
My guess is C9a/b are in parallel and one is hand selected and soldered as a cheap way to trim this part of the circuit.
exxocet:
--- Quote ---
I would wager I could kill a brand new UT61E without anything more than the dry winter air, the carpet in my office, my metal desk and my hands. Sounds real industrial. :-DD
My guess is C9a/b are in parallel and one is hand selected and soldered as a cheap way to trim this part of the circuit.
--- End quote ---
Yeah, while all the other components look industrially soldered (you like that, ah? ;D ), it's always C9 that seems hand soldered. Badly soldered.
PS: I've re-soldered those schmucks and C9a is in fact two capacitors, one on top of the other.
joeqsmith:
I do like the
--- Quote --- it's a great DMM if you're not dealing with industrial voltages/currents, as most of us never do.
--- End quote ---
. I understand that lack of robustness may be considered a desired trait as the meter being damaged easily provides the user with an indication that their meter was exposed to something that may cause it to fail later on. For these people, it will be hard to beat the UNI-T brand!! :-DD
So three capacitors in parallel? This sort of makes sense. Labor is cheap. Start with the large part, add trimmer one, then a fine trim. Does not look great but gets the job done.
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