Hi,
I add the comment to my last post but I didn’t have any answer that why I start a new thread.
The S6 switch doesn’t work. I test all the connection and they are alright. I look at the voltage on the S6 pin and I have :
* On the pin 1 and 2 of the S6, the 10k resistor and the pin 13 of the 74LS165 i have 0,6 v.
* On all other switch I have 5v on the same pin.
Do you have any idea why the pin 13 of the 74LS165 is at 0,6v and not 5v like the other.
Philippe
With the circuit powered off, what is the resistance between this pin and +5V?
On pin 1 and 2 of the S6 switch I have 2kohm with the 5V and with the ground 1,25 kOhm.
On a another switch I have 9,9Kohm with the 5V and 10 Kohm with the ground.
On pin 3 and 4 I have 1,03 kohm with the 5V and 0 with the ground.
Any idea? Need some more test ?
If you look at the schematic/PCB layout around S6, you’ll see how little there is to go wrong.
I don’t think it could be more than 4 things… Broken/shorted track on PCB around S6? Bad IC2? RN1 incorrectly soldered? (check orientation). Switch itself?