Recently purchased K8055N in kit form. Already had preassembled older version VM110.
When first tested ld11 came on but nothing from ld8. Searched forum for clues. no success.
There are two components which I had difficulty in orientating - the crystal and the voltage regulator. For the crystal I refered to the older version board and found that the writing on the casing faced the nearby IC3. The voltage regulator didn’t seem clear at all but looking at the photo on the kit packaging realised I had it the wrong way round. Changed it and it works perfectly. Heat sink should face ic4 and not the usb socket.
Crystals don’t have any polarity, so like for a resistor, orientation is cosmetic.
Having had the voltage regulator placed the wrong way should not have done any harm (by itself). The LM317 put in reverse in that configuration should produce less than 3V on the output pin, so that alone cannot have fried the PIC.
LD8 not blinking on connect means that the PIC isn’t starting. That blinking is actually done by some debugging code in the Microchip USB framework useful for driver development. The framework toggles that output at certain stages in the USB enumeration process. So the LED not blinking the appropriate number of times and being off after that tells the driver developer where in the enumeration process the driver/firmware communication failed.
Fortunately nobody at Velleman ever cared to remove that debugging code. Since activating the USB stack is the first thing, the firmware does, we know that the PIC isn’t running at all.
Unfortunately this forum doesn’t allow uploads. Can you please take “sharp” and “high-resolution” pictures of both, the soldering and the component side of your K8055N, upload them to some photo sharing site and then post links here?
Jan,
I posted this because I got the orientation of the voltage regulator wrong (others may do the same). But I corrected it and the card is now working fine. Therefore no longer a problem.
The orientation of those components is actually indicated in the silkscreen print on the PCB. The voltage regulator is in a TO220 case and the component outline on the PCB has a double line facing IC4. That double line is where the heat-sink goes for anything in a TO220.
I have the same problem with my freshly assembled K8055N. When I connect the board to USB, LD11 is active, but LD8 remains dark. Also no USB device connect pop-up from windows or anything.
And I haven’t soldered VR1 in the wrong orientation.
I uploaded photos to imgur.com/a/Y4zfn.
Oh and the USB cable works fine with my Arduino.
Best regards,
Christian
I’m sorry for the inconvenience.
It seems the problem can’t be solved in this forum
The photos show that the board assembly and soldering quality are excellent.
Also the voltage levels you measured are OK.
It seems anyhow the PIC micro is not running at all.
You can return the kit for inspection/exchange to your distributor or to:
It looks like one of the solder pads for R3 going to LD8 is lifted.
This will not make the board work but may give an indication of the failure
Like I said it looks like it’s lifted It’s hard to tell from the picture.
I seem to experience the same problem with my new K8055N board.
Messured the voltages as shown in this topic. They seem to bee ok.
LED 8 doesn’t blink. No recognition of the board by the computer.
The question if it would be possible to send the PIC only hasn’t been answered.