Extreme Frustration with Circut Board Power Connectors

Community General Discussions
1

Please understand how much pride I am having to swallow in admitting defeat, revealing my inadequacies, and writing for help. :blush: :blush: :cry: But I have been a model builder and model railroader for about 64 years, and I canā€™t remember ever having such difficulties with a seemingly elementary part as I continually have with the green power connectors on the various circut boards - specifically with the VS connectors intended to clamp the larger gauge wires.

I first had problems with my BRATā€™s Bot Board II. I solved that by cutting away enough strands until the wire finally entered the connector. I later read where Robot Dude advised someone else that it was necessary to twist the wires very tightly with pliers to fit them to the connectors.

Next was the SSC-32 in my T-Hex. Even after twisting the wires almost to the point of failure, I couldnā€™t make it work. After fiddling around quite some time, I discovered under magnification that the connectors were opening wider when I screwed them clockwise. That is certainly counterintuitive, but it did work. After resetting the jaws and connecting the wires, the jaws then tightened by screwing them the normal clockwise.

These two boards use individual two-wire connectors for VS and VL. At least the screws did open and close the jaws.

Now I have an AL5D arm with a BotBoarduino. It uses a four-wire connector. After nearly an hour under high magnification, I cannot detect that the screws are having any affect on the jaw openings at all. Whether I move the screws in or out or in the middle the jaws remain the same. I canā€™t even move the jaws further apart with a pointed probe. There is no way the VS wires will enter.

My frustration is heightened by the knowledge that these are simple, standard parts that see many uses throughout the hobby industry, and that any idiot can use them. Except this idiot. :cry: :cry: :blush:

Perhaps if you could post an exploded view of how the insides of this connector is built so I could see what is supposed to move in relation to what, it would help. As it is, I donā€™t know if this a two piece sliding jaw as on the SSC-32 or a one piece, squeezible part. I really hate to apply any more force until I know what is intended to happen.

Sorry if this seems like a rant, but you really shouldnā€™t seduce an old man with promises of paradise and then mess with out pride. For some of us it may be all we have left. :smiley: :smiley: :wink:

Thank you,

2

The small terminals can be finicky, but I stand behind the use of them with our wiring harnesses. I have never needed to use pliers to get the wires twisted enough. Doing it by hand has always worked for me. All of the wires straight and neatly twisted. If on the other hand the wires are all mangled then of course more attention will be required, and possibly hand toolsā€¦ I do recommend the builder look inside the opening of the connector while adjusting the screw to see when it is open all the way. Throw out all assumptions and just look at it.

The larger connectors on the Botboarduino are a direct result of people complaining about the smaller ones. They have 4 complete turns from open to closed. I recommend you turn the screw CCW until it clicks. Push a tooth pick into the opening to push the metal plate up before trying to install the wire.

I am sorry you are having trouble with the connectors.

There is little I can do about the problems you are having with the connectors.

3

Jim,

Thanks for answering so quickly. You confirmed for me that I was on the right track; it just wonā€™t work!

First, I agree finger twisting the wires should work if I didnā€™t have 73 year old arthritic fingers. But using a small pair of flat nose pliers with light pressure works just fine. I get a nice, tight, round twist with no mashing or straggly wires.

Second, I applaud your decision to go to the four-wire connectors. They are easier to grip and thus prevent twisting them on the circut board by over torquing the screws as with the two wire connectors.

Third, I think there is a defective connector on my BotBoarduino: I backed the screws out as you suggested. Forget a soft, breakable toothpick, I used a longer steel pointed soldering aid that fits far enough into the connector clamps to apply some real leverage. The two VS clamps and the VL+ clamp absolutely refused to budge. The VL- clamp would open some but closed immediately when I withdrew the pointed tool. The two VL clamps will accept the 9V wires, but the VS clamps will not accept a 1/8 drill which s slightly smaller than the VS wire.

I tried soldering some heavy grade paper clip wire to the ends of the the VS wires to act as ā€œplugsā€ into the VS sockets. But since they have to be in a straight line with no way to make a good mechanical connection before soldering, that didnā€™t work either.

The screws do hold anything that will fit into the clamp even if the clamp doesnā€™t open or close.

So, Iā€™m thinking a solution might be to simply drill a larger hole in the faces of the VS clamps, and let the screws do all the holding. I have a MicroMark modeling drill press that would make this very precise. However, I donā€™t want to do this without your permission. This could solve everything without having to swap the board for a new one.

Again, thanks for the informative reply. I didnt feel like I was working in the dark anymore.

4

Ted, do whatever you need to get it going. Let me now how it works out. If something is defective I will replace it.

5

I actually had the same problem, the connector was a bit tiny for my liking and I broke them from using them too much.
I ordered some new ones off sparkfun and installed them onto the circuit boardsā€¦ This is kind of above and beyond what a normal user would want to do.

I would think if the botboard 2 and SSC boards were remade from scratch they would probably have larger connectors on them or something a bit beefierā€¦ but again thereā€™s a million types of connectors and my personal preference is probably different then someone elseā€™s preferenceā€¦

I installed these sparkfun.com/products/8084

Any time a device is used for development and being disconnected and reconnected the way its designed has to be taken into considerationā€¦ for power connectors I like overkillā€¦ but then again for 90% of the people out there stuff like this really isnā€™t an issueā€¦ Iā€™m that 10% that finds faults in all sorts of electronics.

I have had my BB2 since about December of 2008 with only one or two hiccups :slight_smile:

ā€“Aaron

6

SUCCCESS :smiley: :smiley: :smiley: but ultimately failure! :cry: :cry: :cry:

I drilled out the frozen VS clamps using a hand tapping fixture and vise from MicroMark:
micromark.com/microlux-tapping-fixture,8363.html
micromark.com/quick-jaw-vise-2-1and4-inch-capacity,8093.html
I was afraid that a power drill might grab the light metal whereas the tapping fixture allowed me to rotate both directions clearing the chip and avoiding a grab. The vise has a vertical v-groove in one jaw which held the circut board in precise relation to the drill. The wires finally entered the clamps and could be screwed down.

So I programmed the board, hooked up everything with fresh batteries and the power supply and nothing!

Voltage checks showed 6.7 volts to the VS screws. Continuity checks showed connection between the VS+ screw and VS pins on the board. But continuity was intermittent between the VS- screw and ground pins on the board. VS- only showed if external vertical pressure was held on the VS- screw head.

Using a probe to do this I successfully tested the PS-2ā€™s ability to control all the arm functions. :smiley: :smiley: But they stopped as soon as I released pressure. Maybe I could add an AL5A arm to pressure the VS- screw. :wink:

Sorry for the epic, but what else is a man my age to do between doctor appointments.

Thanks for the hand holding, Jim, it made me feel safer about experimenting further on my own. I know this arm will work and be fun.

7

Bump?

8

If it were me and only a gnd connection, I would be tempted to connect both batteries to vl gnd, probably using a wirenut, to connect to one wire. Also would check for cold solder joint, and resolder just to be sureā€¦

Kurt

9

Maybe using an old-school terminal strip would work better for you? Run leads to it from the PCB. If a connector is damaged, you can often solder wire leads to the ground and power buses. Not pretty, but consider it.

Alan KM6VV