Seven segment display odd issue

[STRIKER10836]

I am trying to repair a treadmill display issue. The seven segment displays show all on but when I place my hand close but not touching over it works. There is no function issues whatsoever. Could it be crystal clock is the issue? I have checked the grounding.

I have not seen this issue before

 

[davenn]

I am trying to repair a treadmill display issue. The seven segment displays show all on but when I place my hand close but not touching over it works. There is no function issues whatsoever. Could it be crystal clock is the issue? I have checked the grounding.


I have not seen this issue before

show an underside photo of the board as well so solder joints etc can be checked

 

[Bluejets]

Left top to centre looks like some liquid spill on the board at some time.

 

[STRIKER10836]

Attached is the underside. There is globs of glue that look like someone previously removed. As stated looks like was some signs of a liquid but no corrosion. Not sure why the display would work normally if i hover my hand over the display.

 

[Bluejets]

Another look at the video it seems all the displays are affected.

Also, where you are passing your hand is directly over the crystal.

Anything obvious there....?

 

[STRIKER10836]

Yes, it does seem that when my hand was over the section with the crystal all the displays work. I even tried while not standing or touching the equipment. I think I may replace the crystal. But wanted to check in to see if anyone has seen and resolved this type of issue

 

[Bluejets]

Don't think that necessarily means a crook crystal.
Placing your hand over the area is more a capacitive effect.
I'd still be looking a bit further into that "apparent" liquid spill. and as Davenn says, crook connections somewhere.

 

[Bluejets]

Do you understand how multiplexing works as it will help you to find your problem...??