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QCX-mini LCD top row is blocks, bottom row is blank

 

Hi, I just completed a build of the QCX-mini. When powering the device with either 7.5V or 12V battery I get ?LCD top row is blocks, bottom row is blank and nothing else. I have checked throughout for solder bridges and found none, I also checked for continuity with digital multi meter and found the IC2 (ATmega328P) to be connected ok with the ic socket and also with the board sockets with no bent pins and proper intal alingment. Also continuity is fine for the LCD. IC2 has clock on pin 10 of 4MHz (measured with logic probe), IC2 also has voltages on pins 2,3,4 and 5. I'm not sure how to fully test IC2 to see if all is good or what else I should look for in the circuit to spot the issue. Any help would be appreciated.

 

On 24/04/2025 22:08, Jeremy Ollerenshaw via groups.io wrote:
I get ?LCD top row is blocks, bottom row is blank and nothing else.
Troubleshooting linked on the QCX page

73 Alan G4ZFQ
 

So this indicates the LCD is receiving nothing at start up
?
Unsoldered /shorted ?connections, ?CPU absent, CPU wrong way round, pins folded underneath etc are all worth checking?
?
Have you read the troubleshooting guide on the units webpages ??
 

jeremy, you should check for continuity between IC2 Pins 2,3,4,5,6 & 27 to LCD pins 11,12,13,14,6 & 4 respectively.? If any are missing check soldering on the LCD, IC2 socket, and pins and sockets on the connectors between the main board and the display board. Those board interconnections are where most of the soldering issues occur. Good luck ... Ron


On Fri, Apr 25, 2025 at 1:07?AM Bruce Akhurst via <bruce=[email protected]> wrote:
So this indicates the LCD is receiving nothing at start up
?
Unsoldered /shorted ?connections, ?CPU absent, CPU wrong way round, pins folded underneath etc are all worth checking?
?
Have you read the troubleshooting guide on the units webpages ??
 

Thanks Ron, I re-worked a few solder joints and was able to bring things to life. Performed alignment and places in case, but now have a couple of other issues to troubleshoot. 1) on power-up, LCD looks normal but text slowly dims to nothing and no functions work. Power-cycling right away brings up LCD with no text and no function. Waiting a few minutes to power-cycle brings up LCD with text which then dies away as before. 2) I performed a factory reset to see if that would help but now on power-up I have a LCD that is not lit but has text 'use original ic' and no functions work. I can see this is going to be a journey!
Jeremy
 

¡°Use original IC¡± usually means that IC2 lost its EEPROM file. You may have to get a new chip to fix it. Sorry¡­ Ron

On Fri, Apr 25, 2025 at 09:59 Jeremy Ollerenshaw via <ollerenj=[email protected]> wrote:
Thanks Ron, I re-worked a few solder joints and was able to bring things to life. Performed alignment and places in case, but now have a couple of other issues to troubleshoot. 1) on power-up, LCD looks normal but text slowly dims to nothing and no functions work. Power-cycling right away brings up LCD with no text and no function. Waiting a few minutes to power-cycle brings up LCD with text which then dies away as before. 2) I performed a factory reset to see if that would help but now on power-up I have a LCD that is not lit but has text 'use original ic' and no functions work. I can see this is going to be a journey!
Jeremy
 

yes, I'm sure that is the case. Must have happened during the factory reset just as power dropped showing a blank LCD. I've ordered another IC2.
Jeremy

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