NCE Powercab: "oily" residue on circuit board

[philsandy]

I have a Powercab which is 10 years old now. When I press the red emergency stop button there isn't always an immediate stop, and I have to press it couple of more times. I opened up the body and found a very light oily residue on the circuit board around the stop contact.

I have seen this before on TV remote controls when the channel changing isn't working correctly. I wiped it all off and this fixed the problem, but over time it appears again.

Anyone else experienced this, is this residue coming from the circuit board itself or the rubber button membrane?

[Gilbert]

I've had a black residue which I periodically clean up on my NCE handsets - I also find my direction button does wear out so I have replaced one pad membrane in the past.

ChrisH

[philsandy]

56 minutes ago, Gilbert said:

I've had a black residue which I periodically clean up on my NCE handsets - I also find my direction button does wear out so I have replaced one pad membrane in the past.

ChrisH

 

Thanks Chris. Actually I think this is the problem, I have to press harder on the emergency stop button, I probably use this  more than any other. There are faint black marks on the circuit board contacts of  emergency stop and direction, but not on any of the others.

[Crosland]

It's the rubber breaking down. An old fashioned pencil eraser is good for cleaning the PCB, but, as you say, the problem will recur in time.

[rogerdee]

I had the same problem cleaned the circuit board and membrane with meths  but it came back after a while, ended up getting a new pad. 

On the bonus side bought a non working hand set really cheap replaced the pad for I think about a tenner and had it fully working for a third of the price of a new one.

[melmerby]

Beware PCBs which have a matt black layer on the contacts.

It's meant to be there and is part of the contact, using IPA and similar to clean them will remove that layer and make them 10X worse.

[Ray H]

I've addressed problems with keys that don't always make contact by placing a small square of the adhesive copper tape on the underside of the button.

[philsandy]

On 24/04/2023 at 17:30, Ray H said:

I've addressed problems with keys that don't always make contact by placing a small square of the adhesive copper tape on the underside of the button.

 

Sent off for some adhesive copper tape, arrived today, it worked a treat, loco stops now with even a light press of the button.