New to the group, hoping to get some advice to get my little tuner going.
What I have is the typical Aliexpress kit, preloaded with 3.2.? I ordered the version that supplies SO-239 connectors and the Auto and Bypass switches.
It went together reasonably well.? The only assembly details that might be of note are:
- the Bypass and Auto connections to the bottom of the board were tough and I may have to revisit them.? Way too small for me to do confidently with a soldering iron. I ended up using two short lengths of the wire left over from the binocular transformer, with the ends cleaned up.
- I was supplied with 8 electrolytic capacitors.? There's only space for 6, so I assume I got two extra in error.? I've seen nothing to suggest they belong somewhere else, like the bottom of the board.
- No wires for connecting the SO-239 connectors were included.? I assumed that an inch or so of unshielded wire would be OK to make the connections to the board, rather than try to convince chunks of RG58 to do the contortions.? The connectors have short ground wires to the board as well.? I didn't run a wire between the two connectors, assuming that the board would do that.
- I didn't put capacitors across the Auto and Bypass switches, something I've seen mentioned while looking for answers (none included - I'm assuming the extra electrolytic caps weren't intended for this purpose?)
- I didn't use the center out of a piece of coax cable for the binocular transformer.? What I had was solid center conductor and kept breaking when I tried to bend it to the necessary shape.? I ended up using insulated stranded wire that *just* fit through the holes on the board.
It powers up.? The display shows Power, SWR, L and C as zeros.? There's a dot to the right of the power line to signify (I understand), Auto mode.? That all looks promising, but the behavior isn't.? I'm seeing a few things that don't seem right, which may or may not be connected.? In no particular order:
- Auto and Bypass switches don't seem to do anything.
- Powering up with the switches depressed doesn't seem to do anything.
- Tune button works as I believe it should - reset with quick press, Tune with longer push.
- When I put RF to the tuner, it makes all the snapping sounds one would expect, then shows an acceptable SWR on the display.
- Power on the display is crazy-high... suggesting my 10 watts is actually over 100 watts.
- Radio shows the same high SWR as without the tuner in line... unless I set the TX power up to maybe 20 watts... then it seems that the clicking and snapping results in something the radio likes.
- The Auto dot indicator will switch to the underscore mark instead, after tuning is complete.? I can't get the dot back unless I power cycle the tuner.
- Transmitting again, on the same frequency will sometimes result in the tuner trying to find a better result.? Sometimes it does, sometimes it ends up failing and the L and C values show as 0.
- When a match is found, the SWR indicated by the tuner might be 1.15:1, but the radio is reporting 1.75:1.? In some cases, the radio reports 'off the scale' while the tuner is indicating a good match.
- On 30m, I saw a match determined, but the SWR reported by the radio continued to rise with 20 watts continuing to the antenna.? This suggests a thermal issue in an inductor perhaps?
I'm at a loss as to what to try, where to look.? I suppose it's possible that there are a few issues at play here, so maybe the first place to check is at the Bypass and Auto connections on the bottom of the board.? I can feel the anxiety building though, just thinking about putting the iron to those spots again... ;-)
I spend some time looking for a procedure to follow to troubleshoot this tuner, but found nothing.
All suggestions appreciated!
73
Brock VA7AV
