No TX, No RX, no LCD #chat


ajparent1/KB1GMX
 

As Fred said some of the ICs use 3.3V, some 5V and a few 12-13V

Likely cause is IC11 voltage regulator in backward or a short from pins 1 to 3.
POOF, happens then.

The parts that do not like more than 5V (give or take 10%):
Microprocessor, (5V max)
SI5351 NPLL (3.3V)
FST3253 (5V)
74ACT00 (5v)

Soldering in the 5351 and FST3253 is SMT tech and if you skills are not up
to it try it, or build another as lack of SMT removal skills will generally
destroy the board..

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


fred.g3srf@...
 

If you do indeed have 13 volts on all IC's, then you have found your fault. You may as well just order a new kit as you will have problems replacing all the IC's that don't like excessive voltage applied and that is pretty well all of them.


Bill Cromwell
 

Heh,

I did not even know there is a chat. Don't look for me there any time soon.

73,

Bill KU8H

On 5/24/20 11:40 AM, Arv Evans wrote:
"Do not reply to this message to post to the chat. You can participate in chats
only through the group's website."  seems rather restrictive and excludes those
who use an email handler and do not directly log into groups.io <http://groups.io>.
My guess is that:
1. The LCD is not being initialized due to a connection error.
2. Soldering the MCU has an error causing the MCU to stop.
3. The whole unit is dead!
There are a number of persons on this group who are very knowledgeable and
seem willing to work with you to suggest actions and solutions.  They may, or
may not, be willing to change methods and work via a chat tool.  Usually remote
troubleshooting involves time for testing, comparing, and this involving time zone
offsets.
Arv
_._
On Sun, May 24, 2020 at 8:41 AM <yannick.hariga@gmail.com <mailto:yannick.hariga@gmail.com>> wrote:
A new chat has been created:
Hey all!
After some months I tried getting my QCX ready for 20m.
Troubleshooting didn't result any positive solutions. Here, some of
the problems:
* No RF power (TX not working)
* Nothing to hear (RX not working)
* After soldering at the ATMEGA (the big one under the LCD), the
LCD just has light on but nothing is displayed
I have 13 Volts on all ICs and I do not find the problems!
I would be really glad about some help!
Thanks a lot in advance and 73s!
Yannick, DK1YH/ON1YH
View/Join This Chat <https://groups.io/g/QRPLabs/chat/6068>
Do not reply to this message to post to the chat. You can
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yannick.hariga@...
 

Thanks guys for all those replies. 

I'll try on resolving those problems

Thank you so much
Have a nice end of the weekend!


Arv Evans
 

"Do not reply to this message to post to the chat. You can participate in chats 
only through the group's website."  seems rather restrictive and excludes those 
who use an email handler and do not directly log into groups.io.  

My guess is that:
  1. The LCD is not being initialized due to a connection error.
  2. Soldering the MCU has an error causing the MCU to stop.
  3. The whole unit is dead!
There are a number of persons on this group who are very knowledgeable and 
seem willing to work with you to suggest actions and solutions.  They may, or 
may not, be willing to change methods and work via a chat tool.  Usually remote 
troubleshooting involves time for testing, comparing, and this involving time zone 
offsets.

Arv
_._




On Sun, May 24, 2020 at 8:41 AM <yannick.hariga@...> wrote:

A new chat has been created:

Hey all!

After some months I tried getting my QCX ready for 20m. Troubleshooting didn't result any positive solutions. Here, some of the problems:

  • No RF power (TX not working)
  • Nothing to hear (RX not working)
  • After soldering at the ATMEGA (the big one under the LCD), the LCD just has light on but nothing is displayed
I have 13 Volts on all ICs and I do not find the problems!

I would be really glad about some help!

Thanks a lot in advance and 73s!
Yannick, DK1YH/ON1YH

View/Join This Chat

Do not reply to this message to post to the chat. You can participate in chats only through the group's website.


@CurtisM
 

Yannick

There is a potentiometer near the display, it must be carefully adjusted to get characters onto the display. That is needed to make adjustments for the rig.
Beyond this the rig has hundreds of solder connections. I had no receive, but using the test generator and my fingers I found a solder joint I missed. First you need a display, after the pot check each display solder connection, and same for control IC. Reflow them if you see nothing suspicious.

Curt


N3MNT
 

Replying here so it may help others as well.
If you have 13V on your IC that is your issue.  Start with the 5V regulator.  If you do not have 5V on the output of the regulator nothing will work.  If you do actually have 13V on the pwr pin of all the ICs, you may have also damaged them.


George Korper
 

Hi Yannick,
Welcome aboard.

Please do this next, go to:
https://www.qrp-labs.com/qcx/qcxtrouble.html

Then if that doesn't help, you need to start checking all the voltages
suggested in the manual. 

Since you didn't mention any smoke, that is a good thing. I wouldn't turn it on again
without a current limited supply or a fuse, and without a dummy load. 

Then it is just a painstaking process, but you will have a lot of information to bring back here. 

Good luck,
George
K3GK


yannick.hariga@...
 

A new chat has been created:

Hey all!

After some months I tried getting my QCX ready for 20m. Troubleshooting didn't result any positive solutions. Here, some of the problems:

  • No RF power (TX not working)
  • Nothing to hear (RX not working)
  • After soldering at the ATMEGA (the big one under the LCD), the LCD just has light on but nothing is displayed
I have 13 Volts on all ICs and I do not find the problems!

I would be really glad about some help!

Thanks a lot in advance and 73s!
Yannick, DK1YH/ON1YH

View/Join This Chat

Do not reply to this message to post to the chat. You can participate in chats only through the group's website.