Awhile back Norman Oklahoma pointed out that the Lemo battery charge socket on the old Trimble Office Support Modules were supported only by their contacts on the circuit board, and were thus prone to breaking. I have a couple of these that I use for charging batteries (and downloading receivers), and on one of them the socket was loose. Fearing that it was in danger of breaking, I decided to take a look and see what might be done to prevent that.
Here's a photo of the socket from the front of the OSM:
In this photo I'm pushing gently on the socket with my finger, and you can see now much it gets displaced. There's a lot of movement there, not a good sign:
Here's a shot of the socket from the back. You can see how the contacts are below the circumference of the socket, which puts a lot of strain on them:
My solution is to fill the space on the top, side and behind the socket with hot-melt glue. Now when pressure is applied to the socket, most of it gets transferred via the solidified glue to the OSM housing, which is cast aluminum and very rigid.
I'm optimistic that this will prolong the life of the charger socket long enough that even I won't need it anymore.
> My solution is to fill the space on the top, side and behind the socket with hot-melt glue. Now when pressure is applied to the socket, most of it gets transferred via the solidified glue to the OSM housing, which is cast aluminum and very rigid.
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The only thing that would concern me about that fix would be the temperature of the hot-melt glue. It looks as if the blob of hot glue descended on some of the electronic components. Wouldn't kneadable epoxy have been as good or better a solution?
Putting the electrical connection with the plugin directly connected to the mother board is just not structural sound.
There should be wires that run from the board to a fixed and well built plugin that is secured to the housing.
I have found that design flaw in many electronic gadgets and many laptop computers sitting in the waste bin because the power connector and sometimes the whole corner of the mother board was broken off.
All for the sake of small footprint.
> The only thing that would concern me about that fix would be the temperature of the hot-melt glue. It looks as if the blob of hot glue descended on some of the electronic components. Wouldn't kneadable epoxy have been as good or better a solution?
The temp at which the glue melts is low enough that it's unlikely to damage any components; it doesn't even burn human skin. (A big enough glob on sensitive skin might be uncomfortable for a second or two, but I've gotten it on my fingers and wasn't bothered by it.)
It also doesn't really adhere to smooth surfaces, and can be removed relatively easily if need be. Epoxy would work, but would be harder to remove.
And one of the nicest things about hot melt is that it cools in a couple of minutes and is then ready to use.
I thought that the *low-temperature* glue had a melting point of around 247degF. Is that too low to be any sort of a problem?
> I thought that the *low-temperature* glue had a melting point of around 247degF. Is that too low to be any sort of a problem?
I've never put a thermometer on it, but that number sounds reasonable given the boiling point of water. I do know that, aside from the "skin test" - which may have more to do with the rate at which the stuff cools on contact with a lower-temp mass than with its melting point - I've used it to completely encapsulate electronic circuits with no ill effects.
I guess some components are more sensitive than others, but in light of my willingness to physically alter my equipment, they'd do well to keep their distance from me. (Did I mention that I drilled a couple of holes in a brand-new Javad receiver?)
> I guess some components are more sensitive than others, but in light of my willingness to physically alter my equipment, they'd do well to keep their distance from me. (Did I mention that I drilled a couple of holes in a brand-new Javad receiver?)
No, I don't think you mentioned that detail. Was it to drain some some of the BeiDou that had backed up in the unit?
I call it Planned obsolescence! I have had to replace a few lap tops for this reason too!:pissed:
> Was it to drain some some of the BeiDou that had backed up in the unit?
No, I believe the Javads have all-in-view draining as a standard feature. I did it to add a modicum of security to an unattended RTK base station:
> No, I believe the Javads have all-in-view draining as a standard feature. I did it to add a modicum of security to an unattended RTK base station:
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Okay, you lashed the JayPS receiver to the tripod to make sure that any thief stole your fixed-height tripod as well? Is this something to do with the deductible on your insurance policy?
> Okay, you lashed the JayPS receiver to the tripod to make sure that any thief stole your fixed-height tripod as well? Is this something to do with the deductible on your insurance policy?
It has more to do with not having to file an insurance claim in the first place, though I think that if a claim becomes necessary it'll be helpful to explain that the equipment was locked.
The receiver is locked to the tripod, and the tripod/receiver/battery are locked to a trap anchor that's installed adjacent to the control monument.
These security measures are meant to discourage opportunistic theft. Anyone equipped with a $150 cable cutter -- or a pair of diagonal cutters, lots of time and really sturdy forearms -- will be able to defeat the system.
> These security measures are meant to discourage opportunistic theft. Anyone equipped with a $150 cable cutter -- or a pair of diagonal cutters, lots of time and really sturdy forearms -- will be able to defeat the system.
Okay, so you're gearing up to discourage the most unsophisticated thief? Why not just have some "Non-returnable in CA" decals made up to replace all the "Javad" stickers?
> Okay, so you're gearing up to discourage the most unsophisticated thief? Why not just have some "Non-returnable in CA" decals made up to replace all the "Javad" stickers?
Him I'm not too worried about, as he'd have trouble just turning things off and packing up the tripod, not to mention falling down on his way back to his car. I'm shooting just a bit higher on the thief sophistication scale. Not way up there, mind, but certainly more capable than a 4th-grader.