Hi Pedro,
There may be two issues here; we'll be lucky if it is just one.
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First we will examine the transmit circuits:? your LPF sweep failure and you 'T' failure in diagnostics point to a problem in the transmit circuitry.? This could be an issue with T501, the LPF toroids or diodes, or with T507.? Yes, I know - that's most of all the transmit stuff you installed.? All of these need checked for good solder joints, proper installation, etc.? But to give a focus point, I'm thinking that since it locks up the processor, a likely culprit could be T507, with a short between the 1-turn primary and the 10-turn secondary on the side that goes to the BNC pin.? Or anything messed up with this transformer.? Until we get it so it won't lock up the processor, and can give us an LPF scan, we won't be able to narrow it down further without using a signal injector and oscilloscope.
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Second, the receive circuits.? The first note is that if the T507 problem is there, it could possibly cause many of the receive problems, so it is best to make sure that is working first.? For the receive circuits, it could be T401 or L401, or perhaps the PCM1804 chip. ?
To check L401, first use the A,B,C,D,E test points on pg 42 of the assembly manual, step 8 as described there. ?(These are in the section for the high-band version of QMX, but apply also for the mid-band version).
To check T401 (trifilar), use the ABC test points on pg 49 of the assembly manual. ?Review all of this section on the build. ?Note that the continuity tests can't test if you reversed any of the paired wires - you would have to unsolder one side of it to do that. ?A on one side needs to match with A of the other side, the same with B and C.
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This all seems daunting, but hang in there - hopefully there is just one or two minor issues causing all of this.
Stan KC7XE
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