How to unplug MATE-N-LOK connectors?

DEC used MATE-N-LOK connectors in various configurations on both the PDP-8/e and VR-14.

The larger connectors with 10 pins (2 rows of 5 pins) are difficult to unplug.

I remember struggling but eventually succeeding with the connectors on top of the VR-14 power supply board.

Today I tried to unplug the connector on top of the large heat-sink in the PDP-8/e power supply.
I pressed the two locking "hooks" towards the body of the connector to unlock the connector and at the same time pulled as hard as I could without success.

Is there some trick to getting these connectors apart?

I would appreciate any advice.

Thanks

Tom Hunter

Tom,
Take a closer look at those hooks, probably due to aging with pressing they will not unlock.
For those occasions use a little pin or screwdriver to unlock them by hand.

Just wiggel, never just pul, but wiggel and pul slowely to get them free.

Inspect all solderings and excamen those big capacitors.
Mostly they are OK after a slow reformation (that is reform the isolation oxide layer within capacitors)

Maurice

I had some difficulty removing a Mate-N-Lok connector in my 8/M. Finally pressed really hard on the remaining locking lever using a screwdriver blade and unintentionally broke the remaining lever off of the connector. When I reassembled the machine the connector fit quite tightly, so I'm not sure the locking levers added much functionality in my case. I ordered new connector shells which fit properly but haven't yet taken time to replace them.

This post has photos of new and old connectors. You can see the old connector which no longer has locking levers on the Power Supply PCB. It's still that way today and works fine.

I assumed that Mate-N-Lok connectors were made of nylon which tends to swell over time thereby making them difficult to separate. Providing there is sufficient room to work, I have had success in the past by pushing a wooden Popsicle stick under the "loop" and against the latching arm, then prying upward, first on one side and then the other. Once both sides have moved a bit, wiggling the connectors apart is much easier. The Popsicle stick seems to be just the right thickness and being made of wood with rounded ends, is able to free the connectors without damage.

I wonder if some dielectric grease on the connector body might make it easier to remove in the future...

I managed to unplug the Mate-N-Lok connector by wedging a small screw driver between the lower section of the locking "hook" the prevent the socket from lifting when I try to lever the connector off the socket. I also used a small amount of contact spray on each pin from the cable ends. I also warmed up the connector body with a hair dryer. Combining all these measures the connector came off without too much effort.

Thanks to everyone who responded.

Tom