Multimeter Repaired For Unstable Reading Problem
Meter on my work bench start behaving abnormally, Digits keeps changing on the display.
I thought it is time for new Multimeter because this problem is may be because of the main IC which is not worth to replace.
In spite of doubt I opened the meter for inspection.
On visual inspection component side everything seems ok so removed the PCB from the case for inspecting back side of PCB. While removing the PCB I feel like Mylar Capacitor is bit like dry solder but when I removed the PCB I found one leg of capacitor is loose in the PCB. I desoldered the Capacitor I found Ripped off pad along with its trace.
It is very tiny trace less then 1mm in width & it very difficult to solder. Managed to solder it under Magnifier Glass for this type of soldering you need needle type thin soldering iron tip or chances are very highly to damage nearby traces.
But this doesn’t work because when you solder from other side this wire will easily come out from the solder so for firmly holding I used “UV Solder Mask Ink”. Now a day’s for electronics repair every technicians must have this “Solder Mask” for jumper work in the circuit.
UV LED light is required for curing the ink. UV LED Light is bit expansive but you can make it in few cents. Just buy 5mm UV LED Will work and it will take 1 Minute to set the Solder Mask Ink in to harden epoxy as well it works as insulator.
In solder mask 10ML syringe you can do thousands of masking I used my tweezer tip to apply. You have to apply in thin layer or it will take long time for curing.
Applied UV Light for 1 Minute & ink gets harden.
Re soldered the Mylar Capacitor back to its location.
Now reassembled the Multimeter for testing and result is positive.
Now digits are stable on the screen.
This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.
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Note: You can check his previous repair articles on ACER Desktop Motherboard Repaired
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Parasuraman S
April 9, 2022 at 10:46 am
Very interesting article! Learnt about UV ink now, though I have heard of it before. Also noticed your own make PCB holder hand! Vow! What a wonderful idea! Many thanks, dear!
Yogesh Panchal
April 10, 2022 at 12:19 am
Sir,
UV Solder mask is very useful for repairing damaged PCB Traces & for insulating Jumper wires. plus point for this ink is when you apply it on peeled off trace it will hold the trace on the place & prevent the trace from further damage and move.
Making something new out of waste material is my hobby & passion.for this PCB Holder i used one CFL Bulb Base cover and filled it with white cement so that it couldn't move because it was full & heavy and fixed one crocodile clip using "Araldite Standard Epoxy Adhesive" over it.
Parasuraman S
April 11, 2022 at 1:49 pm
Very interesting indeed. I would like to make one for my use! Many thanks for sharing this valuable knowledge!
Albert van Bemmelen
April 9, 2022 at 2:24 pm
I heard about UV hardened superglue which I also have used in the past but I never had heard about the UV Solder Mask Ink you used. Thanks for sharing this interesting repair tip!
Yogesh Panchal
April 10, 2022 at 12:25 am
Albert,
This ink is commonly used in mobile phone repair work.
This is real practical learning how this UV Light & rays are behave when it interact with some chemical in our body.
Siva Murugan
April 9, 2022 at 2:51 pm
Where we can get this UV ink.in India Please Share the link. Thankyou for nice information. Regards.
Yogesh Panchal
April 10, 2022 at 12:35 am
Siva Murugan,
I am located in Mumbai & i brought it from our local market from vendor the who deals to supply Mobile repair Parts & tools. I think you are from south.buying from On-Line is always expensive because of Logistic charges. just find it out in your nearby locality in Mobile Parts supplier SHOP.because Mobile repairer use it regularly or you can search on the net in the name of "UV Curable Solder Mask"
this ink available in four colors RED,BLUE,GREEN,& Clear.
oprava pl.
April 9, 2022 at 3:16 pm
OK. Good job
Yogesh Panchal
April 10, 2022 at 12:36 am
Thank you! Oprava pl.
Waleed Rishmawi
April 9, 2022 at 3:34 pm
good repair job and thanks for sharing. yes I have used the soldering mask for about a year now and it is great. it holds the wires steady on board and cover exposed wires as well. yesterday I had a gate contorl board and I was able to cover all the burnt areas due to a lizar attack on that board. have a blessed day
Yogesh Panchal
April 10, 2022 at 12:38 am
Thanks! Waleed,
Some specialized tools make our job Comfortable.
Arun Kumar
April 9, 2022 at 3:48 pm
Good job Yogesh,
Even I appreciate your ingenious idea of the stand.
It is not how much we saved it's the pleasure that we get is much more valuable.
Yogesh Panchal
April 10, 2022 at 12:48 am
Thanks! Arun Kumar
As per the quote"invention is mother of necessity" which i primarily try to make it my self from the waste material i have, its my hobby & Passion & if not succeeded for any reason there are many good quality also available in the market at extra cost.
mike
April 11, 2022 at 12:30 pm
Interesting repair, i have been wondering for a while, what is this mysterious cement dentists use with a pen UV light to repair the teeth of theirs customers 😉
Yogesh Panchal
April 12, 2022 at 12:38 am
Hi Mike,
Yes indeed this new technology is used by dentist for filling the Cavity in tooth using UV Glue & result is we can drill & Grind the Glue after curing using UV Light.