Trouble disconnecting wire in Isomac Millenium

#1: Post by **RPac** » July 17th, 2019, 7:01 am

Greetings,

I am sorry to bother you guys with something so simple but I am in the process of replacing the pressurestat in my Isomac Millenium and I am struggling to disconnect the wire that shows in the picture...

I managed to disconnect two of wires just by pulling but the one in question seams locked. Do I require a special tool to do it?

Thank you for all your time and attention.

Kind Regards,

Rod

#2: Post by **BaristaBoy E61** » July 17th, 2019, 10:47 am

With power 'OFF', I would try wiggling the connector side to side while pulling up. Check to see if there is some sort of 'Clip Release'. If that doesn't work you could try a thin item such as a chisel or a screwdriver along the bottom edge where it mates to the switch or sensor and try prying it up from there. Or pliers along the sides for greater grip and pull upward and off the tab.

Hope that helps!

#3: Post by **stefano65** » July 17th, 2019, 10:56 am

If gently with needle nose pliers doesn't do it
GENTLY and with of course power off
wedge a small flat blade between the micro and the faxton cover and side to side wiggle.

#4: Post by **Nunas** » July 17th, 2019, 11:01 am

Those look like push-on-pull-off connectors, which is what we see in most espresso machines. Since it is on the pressurestat, and since most of them are directly in the high current (heater) circuit (unless there's a relay), it could have become welded on (or corroded on). I agree with BaristaBoy's advice to wiggle, pull and pry. It should come off. Since you're replacing the 'stat anyway, if you can't get it off through muscle power, you would always crush the plastic and remove the female connector through destruction, then cut it off leaving the wire as long as possible. Of course, you'll need to crimp a new one in its place. I'd only do that as a last resort. Generally, though, the corrosion or welding should not be bad enough to permanently affix the connection.

July 17th, 2019, 11:37 am

Thank you all for your kind replies. I am very grateful:)

#6: Post by **Nunas** » July 17th, 2019, 2:02 pm

No worries. In rereading my earlier response I noticed something missing. That is, if there is evidence of overheating of the connection, such as annealing or welding, with or without corrosion, you should change out the female connector rather than try to clean it. Once they are over heated, we are tempted to squeeze the female connector together a bit with pliers. Such connections don't usually last long, as the heated metal will have lost some of its springiness.

#7: Post by **ira** » July 17th, 2019, 2:14 pm

Some of those italian connectors have lock tabs that make them very hard to remove. You can see the lock in the middle tab in the picture. If the tab it attaches to has a sharp edged hole that perfectly catches that tab it can be extremely difficult to remove them.

Ira

July 17th, 2019, 2:46 pm

Thank you all for your precious help:)

In my particular case I had to use a small screwdriver to press the "thingy" at the end of the cocktail stick to release the lock tab and allow the removal of the connector. Good grief... At least it wasn't welded:)

#9: Post by **Nunas** » July 17th, 2019, 3:27 pm

I'm happy to see that you got it off intact and that it looks clean. When you put it back on, that 'lock tab' is actually intended to be a stop for male connectors that lack the two little shoulder stops. The connector was pressed on way to far by whoever messed with it last (or someone at the factory). The actual connection is intended to be mainly on the sides of the two rolled-under parts. There's also an actual 'lock' on press on connectors (Ira's photo). Notice the back of the connector has two grooves and the bit of metal between usually has a bump on it. Look at the male connector to which it mates; often you'll see a little hole or a dimple into which the bump is supposed to fit. If the connector has not overheated, you can press that part with the bump inwards. You can also gently press the round bits back together if they became deformed by pressing the connector on too far. It isn't good engineering practice though; in the lab we just cut damaged connectors off and put on new ones. Since this is likely a high current circuit supplying the heater, you need to have a good solid connection here. H-B has tonnes of photos of such connections that were loose, overheated and took out other components, usually annealing the wire and melting the insulation in the process.

#10: Post by **jgrosjean** » October 22nd, 2019, 7:02 pm

ira wrote:Some of those italian connectors have lock tabs that make them very hard to remove. You can see the lock in the middle tab in the picture. If the tab it attaches to has a sharp edged hole that perfectly catches that tab it can be extremely difficult to remove them.

That's a better picture of what I'm dealing with here:

Tips for separating wire disconnects?

I'm certainly finding some of them hard to remove. Is there anything I should be doing besides pulling and wiggling back and forth?