This is why you don't buy cheap multimeters.

[cdicky]

Re: This is why you don't buy cheap multimeters.

Has no one hear heard of Avo ?
Old skool but the best analog meters

[popeye]

Re: This is why you don't buy cheap multimeters.

Hello. My name is Jim and I go by the user name SparkeyJim. I am new to the forum. I am currently working on LCD and plasma televisions and would like some input. What cap meter or LCR meters would you recommend for smd and mini alum caps on these sets.
Many thanks to those that respond. I will respond in kind.
Thank you, Jim G

Hi Jim

[I] have a Peak atlas esr+model esr70

one of the best investmants I have made.It will display the capacitance and esr value of the caps.

[budm]

Re: This is why you don't buy cheap multimeters.

They probably do wear safety Glass either, does not mean it is safe unless you have spare pair of eyes. I have OSHA to deal with.

[stj]

Re: This is why you don't buy cheap multimeters.

i'll tell you for a fact, my lead-free solder is almost smokeless - the flux stays on the board.

and in 30years of this industry i have NEVER seen an engineer wear gloves.

[mariushm]

Re: This is why you don't buy cheap multimeters.

Apparently latex/regular gloves are super expensive in your country.
If you solder a lot, there's no justification for not using a 50 cent pair of gloves. Same reasoning, if you solder a lot you can afford to buy a ventilation system to pull away all the smoke and keep you/employees healthy.
We're talking regular home users.

And no, lead in lead solder does not break from the solder wire to enter your bloodstream. If you're really paranoid, you can impregnate a paper tower with isopropyl alcohol and wipe the solder wire before using it. OR you can just use gloves if you're paranoid.

As for flux :

OKI :

PRESS INFORMATION
Lead-Free Solders Increase the Need for Bench-Top Fume Extraction

Research has shown that the fumes and vapours emanating from lead-free solders may be more
dangerous to workers and to the environment than those emitted by traditional lead containing
solders. A study by the Danish Toxicology Centre assessed both the toxicity of lead and the metals
used in lead-free alloys. While lead was highly toxic to humans, silver, a standard constituent of
lead-free alloys, was found to be several orders of magnitude more eco-toxic than lead. In
addition, some of the other metals used in lead-free alloys were shown to have uncertain
toxicological results.

“As is so often the case,” says Karl Schuepstuhl, Global Product Manager, Fume Extraction of OK
International, “the best intentions seem to have unintended consequences. The long-term health
aspects of breathing fumes from lead-free soldering processes have not yet been fully
researched. However, it is possible that the health risks posed by alternative alloys may be
greater than those posed by lead containing solders. Many in the industry have accepted on faith
that lead-free alloys are safer. If this unproven assumption results in less vigilance in
protecting internal air quality, electronics manufacturers may regret this lack of foresight.”

Unfortunately, most research projects concerning the use of lead have assumed that eliminating lead
will have a positive effect on the health of workers, while ignoring the possible adverse health
effects of lead substitutes – particularly at the level of the bench- top where workers are “face
to face” with potentially toxic, but invisible, fumes, vapours and gases.

Since lead-free processes require higher soldering temperatures, chemicals and materials are likely
to become airborne in greater amounts than was the case with lead containing solders.So, it is
likely that the use of lead-free solders will increase and not decrease evaporation from metals and
fluxes. And the concentration of activators found in fluxes used in lead-free solders, typically
chemicals that are allergenic and irritating to the skin and eyes, is often double the level of
those in lead containing solders.

Weller : http://www.wellerzerosmog.com/health_risk/

LEAD-FREE SOLDER

The transition to lead-free soldering has reduced strain on the environment, but for the operator, the hand soldering process has become more dangerous. The lead in the solder is gone, but to get the solder wire to flow properly, substantially more flux must be used.

The temperature needed to create a good solder joint using lead-free solder is also higher, causing a stronger reaction within the flux and creating more solder smoke with a greater number of particles. Lead-free soldering produces up to 250 % more particles between 0.5 and 1.0 microns in diameter, the size that is the most dangerous to inhale. In addition to particles, solder smoke can contain isocyanates, aldehydes, and other unhealthy substances.

Lead-free soldering causes up to 250 % more particles in the breathing zone … roughly 20 million particles between 0.3 and 1.0 microns in diameter per cubic foot, or about 700 million particles per cubic meter.



Standard lead-free 3% type ROL1 no-clean flux solder wire was melted continuously with a standard iron. The suction nozzle of a high efficiency fume extraction system was positioned near the tip of the iron. Just 90 minutes later, a nozzle-mounted net had captured a substantial amount of particulates.



BEFORE --------AFTER 90 MINUTES OF LEAD-FREE SOLDERING

This test distinctly shows the importance of using a fume extraction system, even when soldering only once in a while or for just a few hours a day. The captured particles are primarily condensed residues from flux. Without a filter system these particles will be partly inhaled by the operator with the remainder spread over the work object and workplace. In contrast, a proper filter system will eliminate not only the particles, but will also catch and eliminate dangerous gases created in the soldering process.

[stj]

Re: This is why you don't buy cheap multimeters.

@mariushm

you obviously never worked in a soldering enviroment all day or you would know that after a day of soldering your fingers look metalic from the lead-dust.
and it can reach your bloodstream.
that's why they banned lead paint for non-industrial use.

and i'm pretty sure my flux is not as agressive as you think.
it's a lot better than the rosin loaded smoky crap i used to put up with.

[Agent24]

Re: This is why you don't buy cheap multimeters.

Leaded is easier to use and it's more reliable so it keeps things out of the landfill.

If something doesn't get thrown away at all, how's that for RoHS?

[mariushm]

Re: This is why you don't buy cheap multimeters.

better for health,

NOT better for health : due to higher melting temperature, lead free solder has stronger fluxes, which are more toxic - the flux smoke hurts you infinitely more than the presence of lead in solder (you don't get lead in your body from soldering, the temperature is not big enough for lead to become "airborn")

cheaper (because it's sold by weight, not length.)

NOT cheaper in all cases, at least if you want to get a good lead free solder (the one with 2% silver and/or 0.5-1% copper)

better flux than a lot of older solders,

It's debatable. It's not necessarily better, but it's STRONGER, more acid, more toxic for your lungs. It has to be because due to the higher melting temperature of lead free solder, most people keep the soldering irons at much higher temperatures, which gives flux less time to activate and work before it's boiled/evaporated by the iron tip.
As I already said, the flux smokes are much worse than lead free solder fluxes, and since most people don't have a ventilator on their desk, you can safely say lead bases solders will be better.

lower resistance.
stronger joints.

I don't feel like checking, but i doubt in practice it makes a real difference.

If anyone cares to search and compare, he/she can start from here:

https://cdn.badcaps-static.com/pdfs/...26c4cf2bd9.pdf

[stj]

Re: This is why you don't buy cheap multimeters.

better for health,
cheaper (because it's sold by weight, not length.)
better flux than a lot of older solders,
lower resistance.
stronger joints.

the only reason to use lead is if you have a crap iron,
but they guy asked about the temperature to set the iron - so he has decent kit.

incidentally, leaded solder from china should be dirt cheap, because THEY cant use it under the chinese regulations that are more strict than RoHS.

they are just clearing old stock.

[selldoor]

Re: This is why you don't buy cheap multimeters.

that will do,
but lead-free stuff would be better.

Just wondering why you would say that? ecological/health view?
its more difficult for a newbie to use?

[mariushm]

Re: This is why you don't buy cheap multimeters.

That solder is quite good, if it is what it says.

If it's really 63/37 that means it's eutectic...solder will melt or turn to solid within a very narrow temperature range of about 1-2 degrees C around the 183c value.

To solder you actually need to set the temperature of your iron higher, because when you put the iron on the copper on the pcb and you have the wire from the connector there as well, both will pull heat away from the iron tip and the temperature may drop below that 183c temperature and you won't solder reliably.
You adjust the temperature to be hot enough to warm up everything in 2-3 seconds .

1. Strip insulation from the wires of your connector.
2. Tin the wires :
2.1 Set iron temperature to about 220-250c
2.2 Clean the tip from oxides with a paper handkerchief or some napkin, add a tiny bit of solder
2.4 Make contact between the wire and the tip and then on the opposite side, touch the wire with the solder wire. Flux from solder wire will pour and protect the wire, then solder will melt and tin the wire.
2.5 Move the iron tip back and forth on the uninsulated wire end to tin it nicely.

( this should take no more than 4-5 seconds, otherwise the insulation of the connector will start to melt)

3. Cut a part of the uninsulated wire, leave just enough to be over that copper pad on the pcb
4. Raise iron to about 250-300c , wait to reach that temperature.
5. Put wire over the pad, or shove it through the hole if there's any
6. Solder wire in one hand, iron in the other
7. Put iron tip in such a way that it touches both the connector wire and the copper pad
8. Bring solder wire to the pcb pad, wait to see enough solder flow to make the connection is made, move solder wire away than a second later remove the iron tip.

Job done.

Here's good video showing tinning of wires : https://www.youtube.com/watch?v=0SnOW2VdCTI

Same procedure as I explained it, but since you probably don't have liquid flux, you're using the actual flux in the solder wire instead so that's why I told you to have the solder wire above, to let the flux flow on wire before solder from the wire actually melts.

[stj]

Re: This is why you don't buy cheap multimeters.

that will do,
but lead-free stuff would be better.

[LENOVO-A880]

Re: This is why you don't buy cheap multimeters.

It does not depend on what PCB you have, it depends on what solder you use.
It's usually written in the specs or even on the roll of the solder...

Does this type of solder wire suitable for soldering on the UNI-T DT830D circuit board?

Specifications:
-Alloy Composition : Sn63PB37 (63% Tin, 37% Lead)
-Melting Point : 183 ~ 193°C
-Flux % In Core Wire : 2.0%

Solder Name:
-KEWEI Sn63Pb37 Flux Core Solder Wire (0.8mm)

Country Of Origin:
-China

[stj]

Re: This is why you don't buy cheap multimeters.

try not to go over 270 or the insulation on the wire will shrink.

[Per Hansson]

Re: This is why you don't buy cheap multimeters.

It does not depend on what PCB you have, it depends on what solder you use.
It's usually written in the specs or even on the roll of the solder...

[LENOVO-A880]

Re: This is why you don't buy cheap multimeters.

Fixing DT830D UNI-T DMM

First of all, this is a hobby of mine and I'm not a pro where I depend on my equipment. So I have had this cheap and old multimeter to only check fuses, shorts (continuity), Ohm tests, and etc. For me, it doesn't make sense to buy another new multimeter just to repair a $20 residue value monitor or test a faulty transistor. Even $20 would be hard to justify unless I'm trying to fix a several thousand dollar LCD or plasma TV.

This DT830D multimeter from China died off a few years ago due to the LCD problem mainly ICL7106 ic. It doesn't work at all now so what I did was I changed 9V battery together with the 200mA fuse (only one) and same thing I get nothing on the LCD display. Finally I found out that the battery block clip +/- terminal has loose contact inside of it and when I gently pulled the negative lead, it appears to come off. I've ordered several pieces of battery block clips and need to resolder it to the UNI-T multimeter board as a replacement to the bad clip.

Questions

1. What is the suitable temperature that should be used on this kind of circuit board?
2. Can I adjust my soldering iron temperature to 250°C for this kind of soldering job?

[momaka]

Re: This is why you don't buy cheap multimeters.

Your original 830D probes are actually still in one piece? Wow. Mine died years ago, so they never had a chance to give me a false reading.

Oh no, of course not. I did fix them (see page 1 or link below):
https://www.badcaps.net/forum/showpo...6&postcount=12

[Krankshaft]

Re: This is why you don't buy cheap multimeters.

Like this?

Do doubt the double insulation on that drill saved the morons life.

[Agent24]

Re: This is why you don't buy cheap multimeters.

Your original 830D probes are actually still in one piece? Wow. Mine died years ago, so they never had a chance to give me a false reading.

[momaka]

Re: This is why you don't buy cheap multimeters.

After playing a bit more with the probes on my 830D yesterday, I found something very interesting.

Up until this point, a short circuit on my 830D would show as 2-3 Ohms (and very rarely 1.8). I though this was just due to my 830D being very cheap - but it's not. Yesterday, I was trying out some spare connectors to see if they can fit in the multimeter plugs so that I could make my own high-current probes (since the original probe wires are obviously too underrated for that). After inserting one of the connectors in 10A jack of the multimeter plug, I selected the 200 Ohm scale and used the red probe (still plugged in its usual place) to see if my connector actually made connection with the multimeter - it did. Not only that, but my multimeter was reading 0.5 Ohms! I though, that can't be right, so I unplugged my black probe, inserted my own connector in the COM plug and measured the resistance again. But once more, the multimeter read 0.5 Ohms. At this point, I pretty much knew what was going on. I swapped the red probe for the black probe, then tested resistance again to my connector in the COM plug... yup, back to 2.2 Ohms.

So as it turns out, the wire for my black multimeter probe does actually have about 2 Ohms of resistance. - No wonder it heats up so badly. Also explains why in the past, my multimeter would drop so much voltage when I was trying to measure current. Now I know. Time for new probes.