First guage failure

[Wolvenar]

I wondered how well these china made amp meteres would hold up..
Think I got my answer today.
This was well under the 20 amps its supposed to meter.

It can be repaired but makes me wonder about the future reliability

[bj]

  Oh-Oh now you have me worried.   Glad I bought some spares.

[Wolvenar]

As did I expecting this.

[Rover]

I'm just looking at the quality (NOT!) solder connections on the shunt.

I'm not impressed...

Sorry... but it just doesn't look well made.

Rover

[rossw]

I'm just looking at the quality (NOT!) solder connections on the shunt.
I'm not impressed...

Sorry... but it just doesn't look well made.

I fear if you go and buy $10 meters from the local "all american electronic bits store" down the road, they will be of a similar origin and similar quality.

Short of paying top dollar and being very picky about what you get and who you get it from, very little these days has the quality some of us older, grumpier folk "expect".

[rossw]

It can be repaired but makes me wonder about the future reliability

Don't take me the wrong way Wolv, but it also looks to me like there may have been some operator assistance to the failure.

Did you restrain the inner nut while you did up the outer during assembly?
It *LOOKS* like there's been some twisting - which still doesn't excuse a poor solder joint - but could go a fair way to explaining the failure.

[oztules]

I have lots of those meters, and no failures in the last 2 years from them....

I fear Rossw may be correct, and wolv..... you need to only tension the nuts against each other.

I find they are made well enough, as the movement works well, and that only leaves the shunt.

Most cheapies don't solder to the rear output tabs, but at least these ones do.... not much more you could do no matter who builds them.

With the other cheapies I have bought  they will always fail on the shunt to bolt internal interface, as they only screw them not solder. Once soldered, I can't see how they can fail unless you physically interfere with the solder joint somehow.....(Wolv???)

.............oztules

[Wolvenar]

No hardly any chance that I had twisted it any to do that. I *did* hold the inner nut as I tightened the connector in.
I know common mistake, but it is a lesson I learned long ago.

There is signs of significant heating as it warped and discolored the plastic around it along with other signs that it's been a while in the making.
So I checked the other two that are in use, and the replacement, so far none of them have signs of this damage *yet*

As it turns out this is not an easy fix.
Try as I might, I cannot get any solder I have to bond to the post, even sanded to roughen the surface.
I cant even get tinning solder paste to tin the darn thing after I removed the entire assembly from the device to try, which appears to be the only way this could have been soldered at all.

The inside is also threaded on this side I will check the local hardware stores tomorrow to find a screw that fits.
Then recalibrate it for the discrepancy that will inevitably cause, by moving the tap wire on the shunt.

[Rover]

From the photo , it looks like the joints were cold soldered... (melted solder dropped on connection...)

This is guess based on the color of the solder, which could be camera effect. It would also influence the conductivity of the joint, as it would be more of a mechanical bond than a true soldered bond

Just my opinion...

Rover

[Wolvenar]

I would guess you are right Rover.
The image at least for that part, and on my monitor is very much what it looks like in real life.

Debating if its worth the effort to fix. Things were only $3.60 per on ebay, so I get what I paid for.