Knucker Fault Finding

[G8XPZ]

Hi All
Finally decided to build my Knucker. Unfortunately it wont power up - the LED is not lighting up. Checked for power and U4 is reading 10 volts on the side nearest to the led.Checking on the test points - no voltage on any 1v2d etc.
Any pointers as to where to go next for checking??

Thanks Steve
G8XPZ

[G3GJA]

With a temporary load resistor on the output of U4, have you adjusted the trimmer on the regulator PCB to give 4 volts?

A 100R would do as a load.

It should be done before fitting the jumper J7 near the LED on the main PCB.

Clive G3GJA

[G8XPZ]

Hi Clive
Many thanks for the reply - I have adjusted the voltage down to 4 volts and then I put the jumper on J7. The led lit! I have the correct voltages on the test points and I have been sucessful in re programming the eprom.
Thanks for your help.
G8XPZ
Steve

[G3GJA]

Hi Steve

J7 was a clever inclusion in the design; without it many people will have powered up the PCB without adjusting the regulator and then taken out the Zener diode that protects the linear regulators and their associated decoupling capacitors from excessive voltage.

Good to hear you have got it working.

73, Clive G3GJA

[G8XPZ]

Hi Clive
I have spent most of today still trying to get my Knucker to receive.
Firstly I updated the portsdown software and can confirm all working ok with my mini tiouner v2. However when I plug in the Knucker it times out every time. I've adjusted this many times but it always times out whether I plug it in first or after power up of the portsdown. I have put a jumper on J1 .
Is that correct for DVB-T on bottom of tuner?

I think its got to be a bad solder joint somewhere. Would you agree?

Thanks for your help in this as I am getting interested in TV again.
73s Steve G8XPZ

[G8XPZ]

Hi
Well i've checked all the joints and they seem fine. Today I read the cqtv article on this where it says on first time power up it needs 40 seconds to initialise.
Here when I powered up for the first time I didnt wait that long so Could this be my problem?
I ve reprogrammed the usb module again but still get KNUCKER Tuner Not Responding. I know the portsdown is "seeing" it as if I unplug it I get a different message to plug a receiver in.
An thoughts would be appreciated?

Thanks
Steve G8XPZ

[G8XPZ]

Hi
some good news.
Well a second check of the joints found a broken track- now soldered and Knucker working!