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Older model QCX LCD lights up , but no display

 

OK, there is more to this story.? This was a functioning QCX,? but it had firmware version 1.00g.? I in my infinite wisdom decided to upgrade the firmware my self rather than just buy the chip.......oops LOL
I get all the cables, down load the software plug it all in and press the button..... I believe I should have not been powering the radio when I pushed the button.....Anyway, afterwards,? the chip did not update and the screen,? while it lights up still displays nothing.? I have since ordered a new chip.? Which has been delivered and installed.? Alas, the same issue? is still present,? The display lights up (Backlight?) but nothing is displayed.? Regardless of the contrast adjustment. ?? When I plug in my earphones I do hear hiss,? so I think? it is receiving?? but I do not hear anything but hiss.? since I can not see to tune the radio I am not sure that it is actually receiving....Any suggestions?? I did check pin 3 and the pot does adjust the contrast between 0 and 5V.

Thoughts on where should I look?

Kevin - W5LNA
 

Next you should probably check for continuity on all pins between IC2 and the LCD. Those are :

IC2 ? ? ? ?LCD
2 ? ? ? ? ? ?11
3 ? ? ? ? ? ?12
4 ? ? ? ? ? ?13
5 ? ? ? ? ? ?14
6 ? ? ? ? ? ? ?6
27 ? ? ? ? ? ?4

73...Ron ?

On Sat, Mar 2, 2024 at 1:33?PM Kevin Welna <kwelna@...> wrote:
OK, there is more to this story.? This was a functioning QCX,? but it had firmware version 1.00g.? I in my infinite wisdom decided to upgrade the firmware my self rather than just buy the chip.......oops LOL
I get all the cables, down load the software plug it all in and press the button..... I believe I should have not been powering the radio when I pushed the button.....Anyway, afterwards,? the chip did not update and the screen,? while it lights up still displays nothing.? I have since ordered a new chip.? Which has been delivered and installed.? Alas, the same issue? is still present,? The display lights up (Backlight?) but nothing is displayed.? Regardless of the contrast adjustment. ?? When I plug in my earphones I do hear hiss,? so I think? it is receiving?? but I do not hear anything but hiss.? since I can not see to tune the radio I am not sure that it is actually receiving....Any suggestions?? I did check pin 3 and the pot does adjust the contrast between 0 and 5V.

Thoughts on where should I look?

Kevin - W5LNA

 

The Backlight only need '12v' power applied to come on.

Most of the set runs on 5v via a regulator - but not the final few Audio OP amps which will generate some hiss..

Perhaps you ruined the first CPU (the instructions are too brief !) but the current one should have been fine.? ? I would proceed as the troubleshooting guide
in?

and?

Do all the DC checks in the build manual but start with is the 5V power there and at 5V !

?
 

thanks will do! as twisted as it sounds,? I am looking forward to trouble shooting this as my trouble shooting abilities are not what they used to be.? It will be great to exercise them again after 40 years.
 

Did you get anywhere ??

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