So I have a Craftsman DMM item no. 82141 as seen HERE.
It is giving me a consistent issue of blowing through the 10A fuses when I use it to take tailcap readings and I have no idea why…
I am not leaving the leads on the subject for longer than 10 seconds at a time nor am I running more than 3A through the meter so what gives? I really hope that this is not an issue of me being a dum-dum…
Is it very old? Can you return it? I suppose you would have already done that, but I thought I would ask first.
You set the meter to 10A DC and move the pos. lead to 10A terminal?
quote from HKJ: "Select DC current measurement and move the plugs to the 10A/20A input terminal. For flashlight measurement it is best to select the highest current range, i.e. 10A or 20A range, this is done to keep the voltage drop in the meter as low as possible. For a multilevel flashlight on the lowest levels it can be necessary to use a more sensitive range, but this is only recommended if the reading can be keep below 1/10 of max. on the selected range. For lights that uses multiple amperes a clamp meter is better (see below)." (from here)
No. I am for sure blowing the 10A fuse (And yes the fuses are in the correct locations). When testing, I take the positive lead from the 200mA socket and plug it into the 10A socket, COM does not change.
While testing, I use the COM lead to hold against the negative side of the battery and the 10A lead touches the flashlight body to complete the circuit…
Reversing the leads will only show as a negative current on your DMM meter , so no ill-effects.
It certainly looks as though you have the meter leads in the right sockets and a 3A current should not blow a 10A fuse.
When you have the tailcap on the torch , can you switch the torch on and off OK ?
With the tailcap removed , when you apply a short-circuit from the torch body to the battery negative , does the torch switch on OK ?
If you use one of your spare 10A fuses as a short-circuit between the torch body and the battery negative , does the torch switch on OK without the fuse blowing ? … If the fuse blows , then either the current is greater than 10A or the fuse is rated lower than 10A.
Well craftsman requires the use of fast-burn fuses…. is this really a necessity? the fuses that I took out are indeed 250V 10A fast burn fuses. Can I just use non-fast burn fuses?
The lights in question that I had used this DMM on indeed function properly (i.e. I can bypass the tailcap with a short and switch modes, tailcaps function properly etc)
However I have not tested the fuse in line with the short, so when I get some fuses I will try that out.
This sounds very strange indeed, the only thing i could think of is that the fuse is rated at 1.0A and the printing looks like 10A, as i’ve had bulbs and fuses that are very hard to read. Also is the fuse actually blown? Maybe the action of changing the fuse can disturb a bad solder joint in the meter which makes connection for a while until the current flowing breaks the dodgy connection and makes things appear like the fuse has blown.
I think the fuses are for CAT rating safety incase one does something stupid or accidental. Two of my old DMM’s dont have a fuse at all on the 10A range. I’ve measured 15A in the past! The leads get warm but the meter handles the power no problem! I would try the slow blow fuse and see if it makes any difference. What i’m trying to say is, replacing the fuse might alter the safety rating slightly if you work with mains electricity, but for flashlight measuring nothing bad will happen at all.