Introduction: Replace the Leads on a PokitMeter
So I had a pokit meter (https://pokitmeter.com/) but the leads got damaged, my son got them twisted up in the retractor mechanism. Sadly Pokitmeter were not willing to provide spare leads, but I had a set of regular multimeter test leads spare.
Opening the old pokit meter is fairly easy, once the battery is removed, the outer transparent cover prises open. Inside are the parts you see above. The leads are clamped and soldered onto the PCB.
Step 1: Remove the Old Leads
Use a small, sharp, screwdriver to carefully prise the clamps holding the red and black leads open a little. Be careful not to slip and desolder any of the tiny surface mount components, or this repair just got a lot more difficult.
Now apply a soldering iron to the clamps and pull one of the leads away. Repeat for the other lead.
Step 2: Solder on the New Leads
Cut the banana plugs off the old leads*.
Tin the wires with a little hot solder.
Solder the leads to the clamps on the pcb, make sure to get red and black the right way around so your meter reads positive and negative the right way, when repaired.
Pinch the clamps shut to provide some strain relief.
*It always pays to leave 2-3cm of lead on the plugs you are cutting off, so you can keep them, and maybe splice them to something else you might build in future. If you cut them off close to the plugs you have to throw them away, as you won't be able to join anything to them later.
Step 3: Modify the Retractor If Your Leads Are Larger Than the Original Ones.
Now you can begin to reassemble. If your leads are the original ones just put it back together as it came apart. Now you are done.
You will need to modify this part if your new leads are round or have slightly larger insulation than the original leads which were flat and narrow to fit into the retractor. I am accepting there will be no retraction of the leads now.
I cut away a little plastic from this part to allow the leads a path out from the housing.
You can now attach the white plastic part to the pcb, make sure the little cover for the fuse lines up with the copper pads for the fuse on the pcb.
Step 4: Modify the Upper Half of the Outer Casing.
Once you have screwed the two white circular parts (and the small white screw retainer) back around your pcb, you can attach this to the lower half of the outer case, the retractor spring fits into the slot, in the lower half of the outer case. Don't wind any tension on it, as this isn't a retractable cable device anymore.
Trial fit the upper half of the outer case over the pcb assembly. Chances are the new leads won't fit through the narrow slots in the upper half of the outer case. So cut a little bit of it away, as in the image. I used small wire cutters to cut some triangular bits out. Make sure they are smooth so they don't abrade your insulation later. Also, make sure you trial fit the upper half of the outer case, then mark where you need to cut out, as the leads only emerge in two places and these are fixed, you have to cut out the correct areas.
Step 5: Refit the Rest of the Case
The main case snaps together. The fuse can then be fitted. It only works with the blobs of solder facing down, and then only if its the right way around. If it doesn't work flip it north to south and try again.
The metal ring-shaped part and the little spring steel that held the retractor button are now spare parts.
Fit the battery, power it up and give it a try.
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