Removing & Replacing a Plug
Back to index

Eventually you are going to need to replace either a cell plug or pin. If you have broken a wire then if the damage is near the plug end then you can cut it back and replace the plug using this method. If the damage is too bad then you will need to replace the whole cable which is a much bigger job and will be described later.

The key parts which you will need are:

A Molex KK 3-way plug. These are sometimes known as PCB connectors (or interconnectors or PCB sockets), with 2.54mm or 0.1" pitch. You will also need a bag of crimp-on terminal pins. I buy my plugs from Rapid Electronics, Part# 22-0822 for the plug and 22-0836 for the pins. They cost peanuts.

Start of by removing the lid and opening up the kidney. Unplug the sensors, remove the o-rings and bolts and put them somewhere safe.

Option A: cut the plugs off and cut the tails back to the right length for you. Trim back the plastic insulation to expose 3-4mm of wire. Use this when the wires are too long or where there has been some damage to the wires.

Option B: Using something thin, like a jeweller's screwdriver, press down the tab on the pin through the hole in the plug. The wire should pull free of the plug with the pin still attached. When the wire is free, either cut the pin off and trim back the insulation or just pull the pin off the wire. Make sure you note which colour attaches to which side of the pin, ou may get weird readings if you fix the plug with the wires reveresed.

Use this when there is no problem with the wire but either the pin or plug needs to be replaced.

Crimp the new pin on to the wire. The pins are designed with two tabs on them. Lay the wire down the length of the pin so that the plastic sheath is just inside the tab on the end of the pin. Using a pair of needlenose pliers, squash the tab around the wire to clamp it in place (if using wirecutters like I am in the photo then be careful not to chop through everything). The next tab down should be crimped around the exposed wire end to form a good connection.

Don't solder the wires to the pins, they are not designed for it, they are meant to be crimped.

Attach any other pins that are to be replaced. I did all three sensors because the cables were a bit long. You want them as short as possible to avoid trapping them when refitting the kidney but not so short that the pins pull out when you remove the kidney.

Remember I said make a note of which way round the wires go in the plug? If you have cut off the old plug and saved it then you are in luck, if you haven't then you have a 50/50 chance of getting it right. If you've got it wrong then at best you will have a "-" sign on the display, at worst you'll have strange readings/cell bahaviour. Remember on a KISS sensor, only the two outside pins do anything, the middle pin does nothing.

Slide the pins into the wide holes on the plug (the narrow end is for attaching to the cell). The pin should go in with the curled end tab facing upwards so that it clicks into the slot on the front of the plug and locks it there. If it sticks then use something to poke it down until you feel the click. If it is twisted then remove it and try again or the wire will come loose eventually.

Fit a cell onto the plug. If the pins are locked then the cell should go on without much force and the pins should stay in place. If a pin gets pushed out then poke it back down until it locks in place. Remove the cell and refit it, the pins should stay locked this time. If not then keep trying, you may even need to replace the pin with another if it gets bent.

Refit the cells and replace the kidney (remember the o-rings!).

Open the beer, congratulate yourself and think about what you are going to spend the money you've just saved by not owning an Inspiration -- yet again another user repair which APD are only too happy to charge a lot for. How many YBOD owners end up missing dives due to getting corroded connectors fixed?

	Start of by removing the lid and opening up the kidney. Unplug the sensors, remove the o-rings and bolts and put them somewhere safe.
	Option A: cut the plugs off and cut the tails back to the right length for you. Trim back the plastic insulation to expose 3-4mm of wire. Use this when the wires are too long or where there has been some damage to the wires.
	Option B: Using something thin, like a jeweller's screwdriver, press down the tab on the pin through the hole in the plug. The wire should pull free of the plug with the pin still attached. When the wire is free, either cut the pin off and trim back the insulation or just pull the pin off the wire. Make sure you note which colour attaches to which side of the pin, ou may get weird readings if you fix the plug with the wires reveresed. Use this when there is no problem with the wire but either the pin or plug needs to be replaced.
	Crimp the new pin on to the wire. The pins are designed with two tabs on them. Lay the wire down the length of the pin so that the plastic sheath is just inside the tab on the end of the pin. Using a pair of needlenose pliers, squash the tab around the wire to clamp it in place (if using wirecutters like I am in the photo then be careful not to chop through everything). The next tab down should be crimped around the exposed wire end to form a good connection. Don't solder the wires to the pins, they are not designed for it, they are meant to be crimped.
	Attach any other pins that are to be replaced. I did all three sensors because the cables were a bit long. You want them as short as possible to avoid trapping them when refitting the kidney but not so short that the pins pull out when you remove the kidney.
	Remember I said make a note of which way round the wires go in the plug? If you have cut off the old plug and saved it then you are in luck, if you haven't then you have a 50/50 chance of getting it right. If you've got it wrong then at best you will have a "-" sign on the display, at worst you'll have strange readings/cell bahaviour. Remember on a KISS sensor, only the two outside pins do anything, the middle pin does nothing.
	Slide the pins into the wide holes on the plug (the narrow end is for attaching to the cell). The pin should go in with the curled end tab facing upwards so that it clicks into the slot on the front of the plug and locks it there. If it sticks then use something to poke it down until you feel the click. If it is twisted then remove it and try again or the wire will come loose eventually.
	Fit a cell onto the plug. If the pins are locked then the cell should go on without much force and the pins should stay in place. If a pin gets pushed out then poke it back down until it locks in place. Remove the cell and refit it, the pins should stay locked this time. If not then keep trying, you may even need to replace the pin with another if it gets bent. Refit the cells and replace the kidney (remember the o-rings!).