Pico tuner help

[cashy666]

Hi all,
I have just built a Pico Tuner V3 but need a little help /advice.
I have followed the build instructions and tests and am getting 4.17v at TP3 but nothing
on TP4, TP5 or TP6 having shorted U4 and U6 (not at the same time). I have checked my
solder joints, although not the best there are no obvious shorts. Are there any further checks I
can do to help identify the problem. I must add that I'm technically challenged so any help would
really need to take this into account.

Any help would be much appreciated as I don't really want to assign this to the " I'll sort it later box"
which is already full to the brim with failed portsdown bits!!!!!

Thanks in advance

73

Dave
G7MEG

[g6hfs]

Hi,

Have you set the power input select link to usb, and programmed the Pico ( has a flashing led) as this controls the 3.3v and 1.1v regulators

[cashy666]

Hi,
thanks for your response.
I had not got as far as fitting the Pico. Following the Wiki instructions it says there should be voltage on TP4, 5 and 6 prior to fitting the Pico. I have no voltage there. Led 4 is lit but no others.
I have since fitted the programmed Pico and it does flash, led 4 is lit and I get a brief flash from led 1 and 2, but still no output from TP4, 5 or 6. I have also noted that led 4 is brighter on usb..

regards

Dave
G7MEG

[g6hfs]

Hi Dave,

So 4.17v on TP3, check U4 and U6 3.3v regulators are enabled by the Pico on pin 2 and input volts on pin 1 on each one, check they are high U5 1.1v pin 1 is enabled already, check all regulator U4,5,6 pins 1and 2 are high.

Brian

[cashy666]

Hi Brian,
I am getting the following
U4
pin1-3.2v
pin2-4.8v
U6
pin1-3.2v
pin2-4.8v
U5 no voltage on either pin 1 or 2.

Regards
Dave

[g6hfs]

U5 1.1v reg is supplied by U4 3.3v reg, if pins 1 and 2 high on U4 and U6 you should have 3.3v on pins 4 or TP4 and TP6, if not check for shorts on TP’s to ground are you supplying power from usb or dc input jack, check JP4 is selected to usb or extn.

Brian

[g0mjw]

There should be output from U4 and U5 if there is a 3.2V on the enable and 4.8V on the input. The only thing I can think of, assuming the correct parts are fitted and pins (including the ground tab) are soldered properly is a short circuit on the output. They have protection and will fold back. Look for a short (actually two shorts), also make sure the 10uF capacitors are the correct way round. A high res photo may help.

Mike

[cashy666]

Hi Brian and Mike,

I have redone the joints on U4,5 and 6 and cannot see any shorts..as with the rest of the board.
I have checked the input and outputs and are as follows

U4
P1 3.2v
P2 4.8v
P4 0v
P5 0v

U5
No v on any pins

U6
P1 3.2v
P2 4.8v
P4 3.2v
P5 0v

TP 4 0V
TP5 0V
TP6 3.2V

Brian, all this is on USB with the Pico fitted

Mike, I will post a picture sometime this evening when I have figured out why the Forum has banned my IP address so I'm unable to post from my PC

Regards
Dave

[g6hfs]

Hi Dave,

If you have volts U4 pins 1 and 2 with no output on pin 4 TP4 3v3d, the regulator maybe faulty, or a short 3v3d as this supplies pin 23 of the nim, you will not get any volts out on U5 1.1v as this is supplied by U4.

Brian

[g0mjw]

U4 is digital 3V3. U5 is run from U4 pin 4. U6 is analog 3V3.

U4 is not working as there is no output on pin 4 even though there is a supply on pin 2 and enable on pin 1. So, either U4 has a fault or U5 has. It is unusual for Digikey or Mouser parts to be faulty, but that's what it looks like.

You are probably using Three Internet if you have been banned....

Mike