I recently bought the K8055n-2. After putting everything together, and connecting it to the USB port it seems not to work. The powerled(LD11) is on but LD8 is not blinking at all. I’ve check all connections on the PIC-chip and it looks all ok. So righ voltage and grnd at the right pins. Moreover all of the pins of the chip are connected correctly and no short cutting is observed. I also switched all the IC’s with new ones (from another board) but still the same. I even exchanged te quarts crystal but still the same. The demo software does not recognise the card. What could be the problem? I connected to board to a labtop and benchtop (USB2) running on Windows 7 Home edition and Windows 7 Ultimate.
Usually the first step is to post links to high resolution, sharp images of both sides of the module here. Unfortunately this site doesn’t allow uploads, so you will have to use some picture sharing site or similar.
If LD8 doesn’t even start blinking, it means that the PIC isn’t starting to run.
You said you have the right voltage and GND at the right pins of the PIC. I assume you meant that pin 20 VDD has 3.3V and pins 8 and 19 VSS/VSS1 are GND, correct?
You should also have 3.3V on pin 1. If not check R42 for a bad solder connection. Next is pins 9 and 10 actually reaching the crystal. If all that checks out OK, use your voltmeter to measure pin 28 while powering on. That’s the one driving LD8. If that stays 0V after power on (when the LED should blink and go steady because no connection to the PC), I would guess you have a dead PIC.
In the meantime I’ve assembled the second board (1 for private 1 for my job). It has the same problem. I’ve checked the following for both boards:
-Pin 1: 3.2 V
-Pin 20: 3.2 V
-Pin 8 and 19: Gnd (all checked with a voltmeter)
-Pins 9 and 10 reach the Crystal
-There’s no shortcutting in either one of the pins of the PIC-chip
-After power on there’s no voltage on pin 28.
So I made the mistake twice or something else is wrong.
Some pictures can be found at the following link:
Have you tried it on a different machine?
Have you tried a different cable?
Just a thought.
What is the OS of you machine?
XP, Win7?
I’ve used 3 different USB cables on 2 different PC’s. 1 labtop (Windows 7 home edition), 1 benchtop (Windows 7 Ultimate). But isn’t it so that LD8 should blink anyway, regardless the PC/OS?
I think it should blink even if you connect it to a USB cellphone charger.
Yes, the LED LD8 should flash twice when the microcontroller power is put on.
Did you use only cored solder wire when soldering the parts?
Problems occur if you used any soldering liquid (flux) when soldering the parts.
In these two cases it was the cause:
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[quote=“VEL255”]Yes, the LED LD8 should flash twice when the microcontroller power is put on.
Did you use only cored solder wire when soldering the parts?
Problems occur if you used any soldering liquid (flux) when soldering the parts.
In these two cases it was the cause:
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That is a good point. With flux contamination the oscillator may not run. But don’t be too afraid of flux.
I always use rosin flux applied with a tiny brush to the board solder pads as well as components. And I have successfully assembled kits with several hundred SMD parts that way. However, after assembly and double checking of all components, it’s “washing” time.
To remove flux and its residue I “thoroughly” clean everything with denatured alcohol and a toothbrush. It’s the stripping/cleaning alcohol that you find in the paint section of home improvement stores. It usually needs several rounds of brushing and rinsing. If there is still a light gray, sticky residue left, it needs another cleaning. Be careful with potentiometers and other parts that are not entirely encapsulated. The first couple of cleaning rounds can carry flux residue into them! Where possible I leave them for assembly after the first rounds of cleaning.
Hope this helps,
Jan
I did use cored solder wire but no liquid flux. 2 types one with lead and 1 without lead (the latter one was more difficult to use). I’ll try to clean the PCB this evening. I’ll keep you informed. By the way, I did not have this problem with the PIC-programmer kit while I used the same solder.
[quote]I did use cored solder wire but no liquid flux. 2 types one with lead and 1 without lead (the latter one was more difficult to use). I’ll try to clean the PCB this evening.[/quote]It seems the solder is not the issue.
You may check the DC voltage on pins 9 and 10 of IC3.
Should be about:
pin 9: 0.88V
pin 10: 1.44V
I cleaned both PCB’s with alcohol, but still the same problem. Pin 9 shows 1,33 V, Pin 10 also 1,33 V (IC3).
I don’t know if anyone looked at the pictures (these are kind of fuzzy)
But it looks like you may have a short on the USB pins.
Can you meter them out?
Like I said the pictures are fuzzy so I might be wrong.
Please check the capacitors C1 and C2 next to the crystal are 27pF (27 printed on them).
Is the voltage on the other board too 1.33V on both pins 9 and 10?
In the picture seems that there is a solder bridge between pins 9 and 10 on the other board.
I’ve measured them out. There’s no short cutting. Between pin 1 (5V) and 4 (gnd) I measure 5,7 kOhm, all other combinations are 12 MOhm or higher. Photos were made with flash to avoid shining.
After submitting my previous post I read the comment of Vel255. I’m afraid that I’ve to admit the world that I need glasses. On both PCB’s I switched 1 27 pF capacitor with a 22 nF. I’ve corrected it and it works on 1 board :-). I’ll do the 2nd one also this evening. I’ll let you know.
I’m happy that it now works. Thanks all to you, thanks for the great support. Now I’ll go for a beer!!!
Enjoy! 
The 2nd one has also come alive. Thanks again!
Hark,
glad you found the problem.
I too have trouble with my eye-sight sometimes. I am far sighted and have tons of floaters. When working on electronics, I use these types of clip on magnifying glasses:
They clip to glasses and can be flipped up/down. They are available at craft stores and usually cost around $5.
[quote=“Wrong Way”]I don’t know if anyone looked at the pictures (these are kind of fuzzy)
But it looks like you may have a short on the USB pins.
Can you meter them out?
Like I said the pictures are fuzzy so I might be wrong.[/quote]
Some feedback on the pictures/soldering job:
The pictures show some solder “splatter”. Little droplets all over the place. This looks like a too hot soldering iron was held to the contact point, then flux-core solder applied to it. This is not a proper soldering technique for this kind of project.
For soldering this kind of kit I would recommend an iron with no more than 15W and a thin, well maintained tip. Have a solder iron stand/holder with a water soaked sponge. A proper iron holder means the iron is held tip “down” during pauses, preventing heat build up. The water soaked sponge is used to frequently clean the tip, again preventing heat build up. A little can of tip cleaner/tinner is also recommended. The stand/holder plus cleaner/tinner cost little. They will prolong the life of your soldering iron tip and make your projects more successful and enjoyable in the long run.
I have never owned a soldering iron that cost more than $30. But I have successfully put together kits with over 1,000 SMD components. The key is proper tip maintenance. The stand/sponge/tinner setup is the foundation of that.
Thanks for the soldering tips. Some of them I already did, but regarding the hot iron you are fully right. Never too old to learn :-).