Re: QCX-mini failure on new build

Timothy Freeze


I can't thank you enough for your help.  It helped me isolate the problem to the main board and I learned a lot about the QCX.  On the first power it up, it was emitting a loud tone through the headphones, then stopped.  I think that's normal? It lasted for about 5-10 seconds then stopped.  I'm thinking that was the failure point.  It possible it was caused by some mistake I made in assembly. From our troubleshooting I think something on the main board is acting as an interrupt to the boot process of the cpu.  We've completely checked the display, substituted the display, and started up without the control panel, all to no avail.

Again, thanks for taking the time to help.

Kindest regards,

From: <> on behalf of Mont Pierce KM6WT <de.km6wt@...>
Sent: Thursday, June 24, 2021 1:24 AM
To: <>
Subject: Re: [QRPLabs] QCX-mini failure on new build
On Wed, Jun 23, 2021 at 02:09 PM, Timothy Freeze wrote:
I just received a complete 80 M kit, built the display, and put the header pin in upside down.  I'm so dumb.  I had to remove the 10 pin header and resolder it in place properly.  Some of the thru hole copper came out, butit appears to work ok. 

I finished putting it together and tried it in the QCX, well it gives the same result.  Sometimes ???or other characters and a flashing cursor to the right.  So I'd guess that means the main board is bad?
Well... unfortunately doesn't sound like a simple issue.  Yes, it does sound like it's on the main board.  But hard to tell from here.  I'm not sure what else to test....  :(

I'm thinking of just sucking it up and order another 20 M kit,  trying again and hoping for the best. 
That's another option.  These kits are inexpensive and well worth the experience.

There are also some on this group that have provided repair services for others.  They might be able to help.

The twisted tabs on the LCD are not bent over.  They don't appear to be touching anything.
That's interesting. on Rev 1 board, the bottom center tab had to be bent slightly to miss the trimmer pots.  Hans must have moved things around a bit on PCB Rev 2 to make room.

I'm out of ideas.  Sorry I couldn't help....


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