No video on transmit

[G8GKQ]

OK Steve

So, please humour me and try connecting J01 the other way round (Physically so that pin 4-1, 3-2, 2-3, and 1-4). You won't do any damage, but it might just work. Everything points to a wiring problem here.

If it works, during transmit the voltage at the junction of R03 and R09 should be 2.5v, and the voltages on I+, I- Q+ and Q- should all be similar at around 0.6V, not 0.3 ish and 0.9 ish.

If it doesn't work, you could do the 5v test on J01 again, and you should see the voltages on I+ and I- change between 0.3 and 0.9v when you apply/remove the 5v. The RPi should make these voltages move up and down (at 333/2 KHz) so that your test meter sees the mid voltage, and that is not happening in the readings that you have given me.

What seems to be happening is that the modulator is not seeing the digital input from the RPi for some reason.

Dave

[G4HTZ]

Hi Dave
Reversed JO1 as suggested ...still nothing...results were
Junction R3/9 4.5v
Volts on I and Q
I+ 0.42v
I- 0.9v
Q+ 382mv
Q- 0.9v

I then put JO1 back to correct wiring.....the I and Q volts reading were exactly the same as above.


Repeated JO1 test as per yesterday request
5v on I+ 383mv. I- 0.97v
5off I+ 1v I- 350mv

Hope that helps but proberly not
Regards
Steve

[g0mjw]

Can you upload a high resolution photo of the board?

[G8GKQ]

Hi Steve

As far as I can tell, the Filter-Modulator board is working as expected. This test:

Repeated JO1 test as per yesterday request
5v on I+ 383mv. I- 0.97v
5off I+ 1v I- 350mv

confirms that the signal path is good from J01 to the input to the quadrature modulator IC.

Your earlier test during transmit gave the voltages on J01 as:

JO1
1 10.7mv
2 1.5v
3 10.7mv
4 1.51v

However, the voltages at I+, I-, Q+ and Q- suggest a problem between where you measured these J01 voltages and the opto-isolator on the board. It really does seem like it could be a wiring/connection issue.

As Mike suggests, please could you post a photo of the J01 area of your board that shows the input wiring, and another photo of the GPIO header on top of the RPi?

Lastly, please describe in detail the Menu changes that you make between successful testing in UGLY mode and then testing with the Filter-modulator. Are you using the Console menu, or just the touchscreen?

We'll get there in the end. Thanks for your patience!

Dave

[G4HTZ]

Hi Dave and mike
Thanks for the help so far .
Will try and upload some pictures..only got an iPad and website says pictures too big ....I can email them to you if you want.

I'm using touchscreen mode , with the latest update ...IQ or ugly mode selected on 2nd menu screen as required

Thanks for help again
Regards
Steve

[G4HTZ]

Hi Dave and mike
I have sent pictures to mikes email on his QRZ page listing.

Dave if you email me at essexsteve@icloud.com I can forward them to you if you wish

Can't get them to upload on here

Steve G4HTZ

[G4HTZ]

Hi Dave and mike
All sorted now
As you suspected a wiring problem !!!!
I bought a brand new pack of adfruit jumper wires for the connections between gpio board and fm board .
3 of the JO1 wires were faulty when I tested them with the meter ...replaced them ..went to tx and minitoune locked up straight away .
Should of checked them in the 1st place ...but assumed as they were new leads they would be ok .
At least I learned something about the FM board in the process .
Will have to box it up now
Sorry to have wasted your time
Thanks again
Regards
Steve G4HTZ

[Roberto48]

Hi All,

I'm trying to get some picture from my Portsdown, but nothing at all....
I tried everything, even the remarks in this treat.
I have attached a screenshot of MiniTiouner and I hope op some eureka....

73's
Rob PA0RWE

[G8GKQ]

Hi Rob

We need some more information before we can guess your problem.

1. I take it that MiniTioune works with PI6ATV, so the problem must be in the Portsdown?

2. Did your Portsdown work in Ugly mode? (437 MHz 333KS)

3. What video source are you trying to use on the Portsdown?

4. What Encoder are you trying to use on the Portsdown?

5. What modulator are you trying to use on the Portsdown? (Filter-modulator Board, DATV Express, Lime?)

6. What Portsdown software version are you using?

Photos of Menu 1 and the Info screen would be useful.

Dave, G8GKQ

[G4HTZ]

Rob

If your using the portsdown I would suggest doing all the checks that Dave and others suggested to me ...see earlier posts in this thread ....in my case it was a few faulty wires ...replaced those and it all sprung into life.

Good luck
Steve