Velleman kit k4306/k4305/k4304 (please help me)

Kits Audio Hi Fi Projects
1

please help me :cry:

I bought one k4306 kit in €39 then i assembled it…
used 12v dc from my pc power supply…right side was working
fine left side was working sometime & sometime had random light…
then i changed the place of lm 3916 had same problem.then
i replaced ua741(both).had same problem…checked all circuit
connections & places of all resistors & polarity of diodes…
found nothing wrong…thought the power is maybe the problem…
bought new ac-dc adaptor of 300MA 3-12v selector…had same thing…
bought new kit (k 4304 [€ 17])…had same problem…the leds lighten up randomly…
no response to audio signal…again bought new kit (k4306[€39]) assembled very carefully…
had same problem as k4304.the leds lighten up randomly…& no response to audio signal …

(I guess i need 2A power supply of 12v dc…)
I was wondering if it will be fine if i use this one:
velleman.eu/distributor/prod … ?id=384790
this one can supply 12v @ 2.5A …

here is a video:http://www.youtube.com/watch?v=F9NL-swsuKU

here are the pictures:
imageshack.us/photo/my-images/683/sdc12586r.jpg/
imageshack.us/photo/my-images/339/sdc12588s.jpg/
imageshack.us/photo/my-images/15/sdc12589.jpg/
imageshack.us/photo/my-images/402/sdc12590m.jpg/
imageshack.us/photo/my-images/827/sdc12591z.jpg/
imageshack.us/photo/my-images/825/sdc12592.jpg/
imageshack.us/photo/my-images/577/sdc12593.jpg/
imageshack.us/photo/my-images/24/sdc12594.jpg/

any help appriciated…

2

What kind of audio signal did you connect and how did you connect it?
Do all leds turn off when you short the input?

3

First of all thanks for replying,my pc has two audio outputs…
1 in front 2 in backpanel…& pc runs winwows 7.from the both
audio out comes audio together…cause it is tied up by software…

(if i connect 3.5mm headphone jack in front it doesn’t effects the other)

so i use the audio out from my pc to give signal …I just want to know is it suppossed to
randomly led the lights when u connect the kit ot power…supply…
cause i don’t think so…you should see the video how the lights go
crazy when i connect the kit to power supply…
here is a video:

youtube.com/watch?v=F9NL-swsuKU

4

The behaviour you get is perfectly normal if you leave the inputs open. The unit picks up hum, hence the readout.
Repeat the test with inputs shorted, as mentioned in my previous post.
If you still get a readout when the inputs are shorted, then most likely your power supply needs extra smoothing.
Adding a 1000µF cap in parallel with the supply voltage can help. Mind the polarity.