Pico Tuner - LNB Voltage? (RESOLVED)

[G1INU]

I will put this here as we don't appear to have an area dedicated to Pico Tuner's.

Brand new build;
Pi4, 7in screen, running Portsdown 4.
Pico Tuner V3 Board
Pico Board V0-11 Fw.
JP3 is shunted to put LNB power to the bottom port.
Port B is selected in Portsdown 4.

I have eternal power to the Pico Tuner and a usb cable from Portsdown to the pico board mini usb.

Red power LED is on on the V3 Board and the green led is flashing on the pico board, which if I am understanding forum threads is correct.

Test voltages on the test points are correct except (I believe) TP 1 which is only showing 0.24v when 13v is selected in Portsdown4, and 3.6v when 18v is selected in Portsdown 4.

LED 3 is not illuminating to suggest a fault on U1.

I have no idea if this going to be a hardware or software issue so Any suggestions on where to start will be most welcome.

Thanks.

[g0mjw]

Perhaps post a photo of the area around the LNB supply?

This is the datasheet for the LNB supply - you can test a few things by checking voltages on the pins

https://www.richtek.com/assets/product_ ... 47A-00.pdf

The pins on the right hand side are the control signals. Pin 4 is the input voltage - should be 12V or so that you are putting in. The ground is the tab on the bottom you soldered through from the back.

So, what do you measure on each pin?

Screenshot 2024-06-20 185130.png (19.72 KiB) Viewed 3322 times

[G1INU]

So, what do you measure on each pin?

All pin voltages test with Portsdown 4 in standby and then with it in Receive mode on screen (Both read the same) and LNB Volts set to 13 Vert

1 : 0.6v
2 :12.25v
3 :12.39v
4 :12.39v
5 : 3.2v
6 0v
7 : 2.44v
8 : 0.89v

When I change LNB Volts to 18 Horiz pins 1 6 7 and 8 increase. Obviously 6 is switching it from low to high. Its just that its not getting the voltage expected at pin 1,

1 : 3.28v
2 :12.25v
3 :12.39v
4 :12.39v
5 : 3.2v
6 : 3.2v
7 : 3.99v
8 : 3.57v

[g0mjw]

Could you do a photo? Perhaps a diode is the wrong way round.

[G1INU]

Could you do a photo? Perhaps a diode is the wrong way round.
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Ignore, uploaded in next message

[g0mjw]

Under the text entry, there is an attachments tab. Upload them there.

[G1INU]

Under the text entry, there is an attachments tab. Upload them there.

[G1INU]

The last 2 were taken during the build yesterday hence why the solder through hole had not been completed.

[g0mjw]

Good photos - can you take a close look at this - are all the diodes the right way round?

Screenshot 2024-06-21 122251.png (715.33 KiB) Viewed 2985 times

[G1INU]

Hi Michael,

Yes it's strangely difficult to get a good photo showing the orientation of the diodes but they are all correct way round, with the cathode to the PCB and the anode at the top.