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QMX+ T507

 

Can anyone confirm the wiring to the PCB is correct in the assembly manual ? Fired up my new QMX for the first time and was somewhat upset that everything was working but no signals were passing to or from the antenna. tracing the signal path back from C445 to the antenna socket I found nothing passing through T507. Sure that it was correctly but removed it temporarily? and jumpered across. Rig is working perfectly now but without SWR protection until I rewind the transformer. Looks as if the PCB was reworked in that area because there is nowhere to put the leftover capacitor lead link, Ha Ha .
 

The wiring is correct in the assembly manual.
It is not uncommon to forget to install the jumper in JP501 (shown in the diagram at the bottom of pg 36), which connects the BNC to T507 output.
It is also not uncommon to have soldering issues installing T507, making sure the enamel is fully cleaned from the windings for a good connection.
Stan KC7XE
 

I'm building a QMX+ and will get to that stage in a day or two but I really doubt that the PCB wiring is incorrect.? I checked some of the connections round T507 and it seems fine.
I've always considered that the wiring instructions for T507 to be totally clear - wind the two transformers one on each side of the binocular core and connect using the holes that seem obvious but people do seem to have the ability to misinterpret this.
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T507 is wired as two separate 10:1 transformers, one through the upper hole of the binocular core, the other through the lower hole.
Holding the board with the RF output in the lower right corner the T507 connections are two vertical rows of 4 holes just to the left of the RF BNC:
  • The top pair of holes are used for the ends of the upper 10 turns of the upper transformer.
  • The upper centre pair of holes are used for the 1 turn wire for the upper transformer, this comes straight from the upper centre left hole to the upper centre right hole, through the upper hole of T507.
  • The lower centre pair of holes are used for the 1 'turn' wire for the lower transformer, this comes straight from the lower centre left hole to the lower centre right hole, through the lower hole of T507.
  • The bottom pair of holes are used for the ends of the lower 10 turns of the lower transformer.
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Hope that helps, if you have a problem then photos showing exactly what you have done will be useful.
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Chris, G5CTH
 

Thanks everyone. I had done everything correctly but in my excitement to try out the rig, not fitted the link in JP501. Obviously skimmed over page 36 as well !

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