[hpsdr] Help! Pennylane has apparently died

[Chris Smith]

Hi

I’m looking for pointers as to where to continue debugging my faithful old Pennylane.

I recently bought a 100W linear to go with my Atlas based HPSDR kit (Metis, Mercury, Pennylane, Excalibur+Trimble Thunderbolt, Pennywhistle, Alex).

When I’d connected all the units up and used ‘Tune' into a dummy load, the set-up ‘took off’ and drew large amounts of current. I immediately (or as fast as my arthritic hands would allow) turned the PSU off. I started to work through the connections between the units and eventually found that a short piece of BNC-BNC co-ax didn’t have braid continuity. Further investigation revealed that neither end of the braid was making contact with its BNC plug! This was the connection between Pennylane & Pennywhistle so I had about 8” of unshielded antenna going into Pennywhistle. No wonder it took off.

Having remade this lead and rechecked every other lead, I tried again only to find I had no RF power going into the dummy load.

To cut an awfully long story short - I found that I had no output from Pennylane. At this point I worried that the RF feeding back into the open braid lead had blown the OPA2674 amps (U6A/B). Further investigation showed that I don’t have any drive to the driver stage at J2 pins 1 & 2. So whatever happened has caused damage much further back in the chain.

I haven’t yet determined whether there are signals on the 10MHz and 128.8MHz pins of Atlas but as the Mercury Rx is still working I assume there are.

I don’t have a Pinocchio extender so probing with a scope is difficult in the extreme.

I don’t have a PC which runs Windows so I use a Raspberry Pi 3 and John Melton’s pihpsdr software. This was working well up to the ‘take-off’.

Any pointers please?

Cheers & 73

Chris G4NUX