K8055 Behaving Strangely

Kits General
1

I recently built a K8055 board and when i went to use it it appeared not to work at all. I played around with it and found it almost works with strange beheavour. If I plug the USB in I have to hold Input switch 3 in order for LD8 to blink. If I hold it I am able to connect with the demo software and control the outputs and see the inputs. I also tried removing IC2 and the board works/connects accept obviously the inputs dont work. Curiously when IC2 is removed inputs 1,2,4,5 report on and input 3 rports off. I have checked my component locations and joints several times I am certain there is more going on here. It seems very odd that it would behave mostly correct but different then intended. I am wondering if there is a problem with my PIC

Thanks
Matt

2

It seems that pins 10 and 11 of IC3 may be short-circuited.
There may be a solder bridge or other short between these pins.

3

It is not a short between ic 3 10,11. I have visually inspected and tested with a multimeter
Any other suggestions?

4

Next test:
Remove IC2 and measure the voltage on pin 11 of IC3.
There should be +5V.
If not, then remove also IC3 and check the voltage on pin 11 again.

5

With IC2 removed pin 11 on IC3 shows ~+2.88 volts with IC3 removed pin 11 on IC3 shows +4.8V

6

Most probably this result indicates the IC3 is defective.
You can return it for replacement to your local Velleman dealer or direct to:

Velleman Projects Tech. Dept.
Legen Heirweg 33
9890 Gavere
Belgium

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