Photo R43 bypass QCX mini.jpg uploaded #photo-notice


QRPLabs@groups.io Notification <noreply@...>
 

The following photos have been uploaded to the AC2SG album of the QRPLabs@groups.io group.

By: john.rogers@...


Dave MM0HVW
 

John hi, Dont know wht the issue is with your QCX, so cannot fathom why you have mods to R43.

I have built two QCX 40m,  a QCX+ 20m,  just completed a QCXmini 30m.

From your photo looks like you may have an issue with T1, When magnified your T1 windings are not separated.
Some of the soldered connections may need resoldering.

I found its easier to assemble T1 if  all the windings are tight,  with clear defined spacing between the main and phasing coils.
When assembling on the PCB the relevant winding start connection is always on the outside the fishh of each winding being on the inside
This ensures the phasing of each widing is correct.
I scape the enamel off  the ends of each winding prior to tinning
Then pass all the inside winding connections into the relevant PCB holes follwoed by the outside windings.
Then pull all windings tight, checking each winding end on the reverse of the board is tinned, I then solder all ends.
Using a 60W Temp controlled iron with multicored solder,  apply liquid flux to each joint before soldering same.  
The iron is kept on each joint for a minimum of 10-15 seconds,  or until the solder bubbles and the joint is bright.

Regards Dave MM0HVW



 
 


Mike KK7ER
 

He is following the troubleshooting guide which calls for bypassing R43.  Pretty brave to do it on top of the SMD resistor!  : )  Best of luck.

73, Mike KK7ER


Steve Z
 

When I was doing QCX mini troubleshooting, I chose to bypass R43 using the bottom of the board -- connecting pin 8 of IC3 to L1 via a 330 ohm leaded resistor. I figured that was easier than doing it on top of SMD resistor R43 -- soldering right on the resistor seemed like a sure way to lose it.

Steve N9SZ