MinitTiouner - Lock, but No picture

[G8YTZ]

Just built two MiniTiouners

One is working fine, the other has an issue, On the Portsdown, lock is shown as well as MER etc, but no Programme Name or Picture.

I've carefully buzzed out the PCB TS_2 data lines, all ok but I noticed an error on the circuit diagram: Pin 36 (TS_2 Sync) on the tuner is shown as going to Pin CN-2/17 on the FT2232H module, but it does not, that's the same on both tuners, so the schematic seems to be incorrect.

The Tuner is correctly soldered, so is the FT2232H.

I've substituted the FT2232H with the other tuner and the FT2232H is working correctly.

I'm beginning to suspect a faulty tuner, but before I unsolder this has anyone else any ideas?

PS all voltages are ok, checked before first power!

BR Justin

[G4GUO]

While shipping Minituner-Express units, I came across some defective NIMs.
They were all fixable and were due to dry joints on the 8 bit bus inside the NIM.
I just reheated all the joints with an iron.
The fault appeared the same as what you are seeing, lock but no picture.

- Charles

[G8YTZ]

Thanks Charles, we will try that!

[G8YTZ]

Charles,

from what we can see there is solder bridge between the upper and lower contacts shorting two of the TS lines to the earth conductor that runs between the pins. It is impossible to resolve it without removing the tuner, so the plan is to swap the tuner as we don't think the PCB tracks will cope with more than one tuner change, Steve G4NHP (we were each building a unit together as a mini build-a-thon) is going to remove the tuner at home with de-solder braid, I've given him another that I had earmarked for my Winter Hill Rx, so hopefully he'll get the unit working ok.

Thanks for your advice, seems you were spot on!

[G8YTZ]

When the tuner was removed the pins were carefully inspected and no soldering faults could be found, so a new tuner has been ordered.

It's actually for a mate, Steve G4NHP who is keen to try out DATV.

Justin.