K8060 help please ?!?!?!

Hi , i purchased the k8060 kit about 6 months ago. i amusing it with the recomended transformer. Initially , i could not get it to work , and so i left it. In the last 3 weeks i sent it to your labs in belgium and they returned it to me fixed , replacing two transistors and fixing some dry joints. I soldered on the transformer , (4 ohm) speaskers and my ipod today and switched on the power. The amp powered up , the led came on and music started coming out of the speakers. i proceded to turn up the potentiometer , but after only a small increase , the (recomended) fuse blew. I turned the power off and replaced the fuse. It blew again… I then decided to do the bulb test and – you guessed it , the bulb came on. I looked over everything and it all looked ok. As i say , the board has been ‘tested’ by your staff , and it did work for short while , until i turned it up.
I have read every other post on siumilar subjects and i think i may need to replace the transistors again. As you can imagine , i’m quite frustrated , although i am a bit of a noivice , i have tested all of my joints and they are all ok and i have followed instructions very carefully !!! I would appreciate any help , as this is part of a dt project due for completion in a week - 10 days !! Thanks , Josh Worthy.

I assume you did not touch the on-board trimmer ?
What is the transformer output voltage ?

Hi , thanks for the reply, I am using a 2x30vac transformer, and no I did not touch the trimmer pot, I assumed that when I sent it in , they would of done this in order to test it ,but even if this was wrongly set up , the red led in the middle of the pcb would still be on ?

Power can be present even when the amp is not functioning correctly.
As you have not posted for a while, are there any updates ?

Hi , I bought and fitted two new transistors, I connected it up an the 60 w bulb did not light (all is good suposedly) the led came on . I proceded to connect up the speaker , iPod and potentiometer - as in the diagram. Again I turned the unit on , the bulb and the led lit up. And no music played. I didconected the speaker and the bulb went out. It seems that the speaker is causing some sort of problem . The speaker is 4" and of the right impedance (4ohms).