This is why you don't buy cheap multimeters.

[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?

[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.

[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.

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.

[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.

[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.

[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

[stj]

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

AVO is for museums.
and they are very expensive.

[lti]

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

I need to figure out how to repair the leads that come with these meters. The ones I want to repair appear to have real 18AWG wire rated for 1000V, and it's even UL listed (E187208). The jacks on this one from Harbor Freight are slightly smaller than standard banana jacks, so standard leads don't fit.

This meter measures 0.9 ohms with the leads shorted, and low resistance readings vary. Sometimes it randomly adds about 5 ohms to the reading on the 200 ohm range. There might be a loose connection in the leads, but I can't figure out where one might be.

[stj]

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

my advice is a bit hardcore - but i'v done it a few times now.

first throw the non-standard cables in the bin.
then get a decent set with shielded 4mm jacks.

then fit 4mm shielded sockets to the meter.

[chozo4]

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

If your multimeter is a bit off there is usually a variable resistor inside that is used to calibrate it. Perhaps give it a try when comparing results with another calibrated multimeter to get the readings matched?

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

My lead-free flux smokes a little bit from the heat if there is excess on the tip otherwise it doesn't smoke. I generally don't use resin core solder for my work and instead silver bearing solder so this paste is always handy. Surely it doesn't help that my soldering paste was manufactured in the early 19th century and contains zinc chloride. Though afterward I always thoroughly clean the board afterward of any and all residue.

[momaka]

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

This meter measures 0.9 ohms with the leads shorted, and low resistance readings vary. Sometimes it randomly adds about 5 ohms to the reading on the 200 ohm range. There might be a loose connection in the leads, but I can't figure out where one might be.

First, you need to make sure the connection inside the handles is solid (if it's not and if you tore the wires out before, you need to cut the handle close to where the probe needle is on the front and re-solder the wire to it again). Once it is, pour lots of glue in the handles so that the wire can't move inside. I usually do this with hot glue. It's not the best solution but it works for quite a while. When the glue starts to break or peel (takes a few months to a year of occasional use), I reheat it with hot air from my heat gun and it holds the wire perfectly again.

The second thing you have to know is that the dial on these cheaper meters is... well... cheap. Even if you have it on the 200 Ohm setting, it may not be snapped-on perfectly. You will find that if you move it around just a bit, you may get a good connection and low resistance. Also, with the stock Harbor Freight probes, my Centech meter measured 1.4 Ohms at the lowest. Removing them from the meter and jumpering the COM and Ohm/V/mA jacks makes the meter show close to 0.2 Ohms. So it's just the stock probes that are crap. The meter itself does okay.

If your multimeter is a bit off there is usually a variable resistor inside that is used to calibrate it. Perhaps give it a try when comparing results with another calibrated multimeter to get the readings matched?

I advise against doing that, unless the multimeter still shows a high resistance even with its COM and Ohm jacks jumpered. For the most part, these meters are properly calibrated from the factory. Just bad probes and craftsmanship that brings them down. Mine had quite a few minor, but annoying, things that needed fixing. After fixing them, I'll venture and say that it's a pretty decent general-use multimeter.

[stj]

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

how about a foto of the meter?

[retiredcaps]

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

There might be a loose connection in the leads, but I can't figure out where one might be.

You don't need two probes to make a shorted connection.

Put the black probe jack in COM and then put the black tip probe in V/ohm and note your resistance measurement. Then do the same for the red.

Also check the soldering quality of the pcb input jacks. As you can see on mine, it has stellar soldering from the "factory"...

https://www.badcaps.net/forum/attach...8&d=1275345583

[Agent24]

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

As you can see on mine, it has stellar soldering from the "factory"...

https://www.badcaps.net/forum/attach...8&d=1275345583

Wow, I thought my Dick-Smith meter was an el-cheapo!

[momaka]

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

You don't need two probes to make a shorted connection.

Put the black probe jack in COM and then put the black tip probe in V/ohm and note your resistance measurement. Then do the same for the red.

+1

The stock leads are still pretty crappy, though, so even with just one of them, you will likely still get somewhat high resistance. As I mentioned, mine went down pretty low with high quality leads.

Also check the soldering quality of the pcb input jacks. As you can see on mine, it has stellar soldering from the "factory"...

https://www.badcaps.net/forum/attach...8&d=1275345583

WOW!
Was it really that bad?
Mine wasn't "stellar" either, but at least it had a fuse installed and no crappy jumper leads like that. This one truly deserves a hall of shame picture. Makes my 13 year old cheapo 830 look like a Fluke compared to this .

I'll post mine today in a new thread.

[retiredcaps]

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

WOW!
Was it really that bad?

Yes. Those pictures are unmodified and I did not attempt to repair/fix/modify the DOA meter.

I still have it and I think the reason it doesn't work is the COB isn't working properly. If I flex the pcb, some digits appear on the lcd. I have fixed a few other 830s that I received for free, but I never use them. It was a good learning and troubleshooting experience.

[momaka]

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

Might need to grind the standoffs a bit to get the PCB to insert more pressure on the LCD screen's ribbon.

I just posted pictures of mine here:
https://www.badcaps.net/forum/showthread.php?t=39320

[lti]

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

how about a foto of the meter?

They're in this thread.

[LENOVO-A880]

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

Fixing UNI-T DT830D Leads

I need to ask some opinions from experienced members here to repair the defective probes that come with these meter. I had done some minor repair like re-soldering battery block clips, remove the crack and bad solder joints and reworked some of the old insulation wire wraps. Please refer to this link from my previous post [https://www.badcaps.net/forum/showpo...&postcount=52]

Finally it can boot up like normal again but now I need some ideas from members here to fix these defective leads appear to have a real 18AWG wire rated for 1000V [AWG_wires]. Then the loose connection at the end of the leads had been cut off so far [leads_connector]. So some soldering works need to be done to attach the probes back to the meter like the thumbnails [probes_cutoff] attached below. This meter also measures 0.5 Ohms with the leads shorted [meter_0.5Ohm].

Questions:

1. Should I remove the probes from the meter and replaced it with a decent set (shielded 4mm jacks). Where can I get a new 4mm shielded sockets?
2. Any other ways to repair this kind of probes which always come with bad craftsmanship from the factories?