Problem- Interact / TNC145 buttons not working

[Mike Woo]

Hi
I have a Series 2 Interact with a Heidenhain TNC145c control.
If the machine has been on for a few hours the "2" button, the " Rl " button and the button for choosing a cycle all stop functoning. The rest of the controls still work.
The three buttons that stop functioning are on two different keypads and are seemingly unrelated.
The first time it happened i checked everything i could given that i dont know much then i smacked the box with a mallet and it was ok again but now it needs to be switched off for a few hours to get everything working again.

I am guessing it is a temperature related thing but i am open to suggestions.

Any help would be greatfully received.
Mike

[machintek]

Is it possible that you have a cracked solder joint somewhere that is causing this?
Maybe Heidenhain can help. Most keypads are a matrix so one fault will affect more than one key.
Second thought is that there must be a ribbon cable and plug from the keypad to a board. This may have come loose, or have a bad connection.

George

[Mike Woo]

Hi George
Thanks for the suggestion.

I cant see much as everything is contained within a casing and dismantling the control is a bit daunting but hey ho fools tread where wise men... etc.

It is the fact that the fualty buttons are on two different keypads that is i think the clue. Perhaps both keypad wiring looms go to the same place? Guess i had better get the small hammers out and venture in there.
Cheers
Mike

[machintek]

Heidenhain can tell you the internals of the control.
Removal is simple.
First back up parameters.
Remove power wires and plugs (they slide out sideways from the back of the control. Four screws in the corner hold it on. It slides out the front.
5 phillips screws hold the top cover on. Boards slide out the top.

George