[hpsdr] Help! Pennylane has apparently died

[Laurence Barker]

Hi Chris

You can't go too much further back than J2 before getting into the digital electronics....

It sounds like the FPGA is still behaving. You could check for a 125MHz clock on the DAC (spectrum analyser or expensive oscilloscope), and see if the input bits to the DAC are toggling (choose say 1.8MHz and most oscilloscopes will be happy with that). Look also at the output of T3. You could solder tiny wires to help with getting scope probes in. 

Where in UK are you - I have a Penelope board and test equipment.





Laurence Barker

laurence at nicklebyhouse.co.uk


-----Original Message-----
From: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of Chris Smith
Sent: 28 March 2017 11:01
To: hpsdr at lists.openhpsdr.org list <hpsdr at lists.openhpsdr.org>
Subject: Re: [hpsdr] Help! Pennylane has apparently died

***** High Performance Software Defined Radio Discussion List *****

Addendum to the following:

PTTOUT on pin 13, PTTIN on pin 1 of J6 are still working as are the keyer pins of J6 (7 & 6?).

Chris G4NUX

> On 28 Mar 2017, at 10:47, Chris Smith <chris at vspl.co.uk> wrote:
> 
> [This sender failed our fraud detection checks and may not be who they appear to be. Learn about spoofing at http://aka.ms/LearnAboutSpoofing]
> 
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 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
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