1. QRPLabs@groups.io

Re: Is my QCX 30 a write-off?

Mike Easterbrook
 

Hi Alan
Thanks for the guidance on the processor upgrading.  I used a $3 USB asp from China, W10 and in-situ QCX. Just had to adjust the clock speed slightly and then  all three processors upgraded to 10.2b in a few seconds.  I was previously apprehensive based on the number of requests for help seen on this site.  I think this related to the number of different combinations of kit and software among users.  For anyone else starting from scratch in terms of knowledge and kit like me, I can thoroughly recommend the above approach.

No failures when I put the new processor into the QCX 30 so now have buttons and rotary encoder back working!  So can now wind back to where I left off with the RX alignment:

1. BPF peaks OK with C1 but max reading on display is only 3.
2. IQ Balance - moving R27 clockwise gives lower reading but minimum not reached even at end of travel.
3. Phase Lo/Hi - no change in reading across full span of R24/17. The potentiometers themselves all checked out OK.
4. With 330R across R43 have been trying to follow signal path with my aging scope. Can just about detect signal but not stable enough to estimate levels.
    Q-channel - signal at IC5 pin7, IC6 pin7, IC6 pin1
    I-channel - no signals anywhere through IC5 / IC7
5. RF out is about 0.5w at 12v and 1.0w at 13.8v

Grateful for any suggestions (main priority is the RX at the moment)

Thanks
Mike





On Sun, Nov 17, 2019 at 7:44 PM Alan G4ZFQ <alan4alan@...> wrote:
> I have been following your great sheet on using USBasp and AVRDUDESS. 
> Am I right in thinking that I can use the same procedure (i.e. chip in
> situ QCX) for both upgrading and loading from scratch - the only
> difference being whether or not the both the hex and .eep files are
> uploaded.  (I have the files from Hans -  thanks Hans)
> I was working through this and only noticed the warning about not
> updating the fuse bits if different from your instructions,

Mike,

Perhaps I should add a little regarding flashing a new chip.
A new chip will need the fuses set to the values shown in my shot of
Avrdudess. Simply make sure they are set to those values and use "Write"
next to those entries. My warning was really so that anyone reading the
page should check with the group just in case any changes had been made.

You may do it all in one, select the .hex, .eep and fuses. Tick "Set
fuses" then "Program!" does it in one go. With a new chip there is
nothing to break, you may try again if something goes wrong. But in a
way doing it all at once makes it feel as though you have not done much:-)

73 Alan G4ZFQ
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