Having trouble getting K8055 to work

Kits PC Related Projects
1

Hi,

I just got a k8055. I soldered everything together as instructed, now when I connect a usb cable, the power light comes on, but nothing else happens.

LD8 does not flash, the computer does not detect anything being connected.

I have checked all the soldered joints, and I have verified that IC3 has power, what should I check next?

Thanks,

Peter

2

If no flashes of LD8 are seen this indicates that the microcontroller IC3 program is not running.
Possible cause to this can be:
IC3 is defective.
Crystal oscillator circuit has wrong component. Check the capacitors C4 and C5 - should be 33pF and not visible breaks.
Check the crystal X1 soldering.

Measure the voltages on pins 9 and 10 to ground. - You can use the USB connector cover as a ground reference when measuring.
Voltage on pin 9 should be about 1.7V
Voltage on pin 10 should be about 2.2V

Check also the voltage on pin 14 of the microcontroller IC3. The voltage should be about 3.3V.
And check that there is +5V on pin 1 and +5V on pin 20.

3

Hi,

Thanks for the quick response, sorry for taking so long to get back to you.

C4 and C5 are 33pF capacitors, there are no visible breaks. The soldering on X1 appears to be ok.

Here’s what I measured:
On IC3:
Pin 1 = 5V
Pin 9 = 0.6V
Pin 10 = 0V
Pin 14 = 0V
Pin 20 = 5V

Does this suggest that IC3 has issues, or where should I look next?

Thanks again,

Peter

4

It seems the IC3 is defective.

Please check this link how to proceed: velleman.eu/distributor/supp … rantykits/

5

Hi,

Thanks again,

I’ll bring it back to where I got it.

I’ll let you know how I get on.

Regards,

Peter

6

Brought it back, they exchanged the entire kit…and now I have a fully functional K8055!

Thanks for the help!

Peter