(tr)uSDX Forum

Can you post a link and maybe a picture? Tnx

Transmiting into the wrong impedance (like no antenna at all, or into a dead short) can fry pa fets pretty much instantly. Tune up with just 9 volts will be safer. Did you take a turn off ALL the coils? Not good if you removed a turn from all the coils ending in 2. Those are for suppressing the harm...

C8 Does not appear to be marked on the board. Big “477 J” on top of mine with the striped end nearest Y2. Yes, when tantalum’s fail they put on quite a show, and in my limited experience it smells bad too. All may not be lost if that is all that happened, you could replace it but be sure the orienta...

Which part is “the 477”?

I see atmega328’s at Mouser both with nothing, P and with PB, with all saying 20MHz Does any one know what the suffix’s mean? AU AN AUR ANR Currently, is PB better than P? The “not recommended for new projects” seem more expensive. But my guess is that they are not better. Some have “2-wire” interfa...

In the past it’s been suggested to replace the mic and be careful not to melt the internals by heating it too much. at JLCPCB it’s Manufacturer INGHAi MFR.Part # GMI4527P-2C-40db JLCPCB Part # C233329 If you compare data sheets, I think CUI’s CMEJ-0627-42-P is a close enough match, I have used it an...

IMG-0653bot2.jpeg Main board bottom Parts C2 47uF 16v 20% x5r Tp (C4, C14) 47uF 10v 20% tant polymer TVS bidirectional 14v pre fuse F Fuse 0.75 amp resettable (1.5 amp trip) S schottkey diode, post fuse, to U2. No reverse polarity can get thru but… runs with a voltage drop :( PF post fuse 12v unidi...

Main board top

(more)Debounce for encoder and 8v reg for display with Schottkey for 5v via usb power, too soon to know any results or to recommend, just flailing around ( the inductors are kinda random ) and sharing. Key to follow in next post.

Per DL2MAN’s BOM, at JLCPCB it’s Manufacturer INGHAi MFR.Part # GMI4527P-2C-40db JLCPCB Part # C233329 If you compare data sheets, I think CUI’s CMEJ-0627-42-P is a close enough match, I have used it and it seems to work ok and I can get it from Mouser or Digikey here in the states. See what others ...

IMG_0674.jpg This is the thinnest PCB version that OshPark does: “Flex”. It’s a bit maybe too thin and flexible, this one is mounted at a bit of a tilt. But, it works! They sell them for 80 cents for 3 with free shipping. The 2 oz. Copper/0.8mm thick ones are only 40 cents for 3, also with free shi...

“ hand select them for best match” yes, exactly, but this is precisely what I am having trouble doing. In real practical hands on terms, who has actually done this and how did you accomplish it? How best to make this happen. Thanks.

I think both 603 and 805 sizes are acceptable, either one or as a mix, basically i think it is a question of can you make it fit. You can parallel caps to get to, or close to, the right value and if really necessary you can stack them like bricks. More important is 100v or more, and cog/NPO and is i...

To make the Tayloe Detector work at its best… I would think having those 4 capacitors well matched/equal in value would be good. In the (tr)uSDX I believe these are C25-28. I have replaced my piezoelectric?/microphonic ceramic caps with non microphonic tantalum ones and I do think the sound is bette...

So is 8v ( or maybe 7.5v? ) not ok?

Quote
by DL2MAN » 30 Mar 2023, 17:22
But the Display itself can only handle 8V.
Unquote

Sorry but I am a bit confused.
Thanks.

Quote: Re: Loss of RX on all bands Post by DL2MAN » 19 May 2022, 05:26 In most cases, loss of RX is something simple like: - Bad / Cold Solder Joint on one of the Coils or SMA Connector - Bad/Non Existent connection between RF Board and Mainboard - Bad SMA/BNC Adapter - Bad Cable When it comes to tr...

On the second page under “Taylor Quadrature Sampling Detector” what is labeled as C35, off pin 16 of U6, I believe, should be labeled C20.

(the actual C35 is on pin 16 of U5.)

73

With the version 1.0 main boards, how are people doing the mod to add C38 & C40 to the lines going to the U9 LT6132 op amp, to make them like version 1.2? Where, physically on the board, do you add the extra caps? So far, the only thing I can figure is to replace the 0603 100 ohm resistors with ...

How does one optimize the filters/spacing on the toroids if one does not have a NanoVNA?

The one from March 19th is clear and essentially identical except R1 is 330 and R5 is 220 on the newer one.

Circuitry confuses the heck out of me. I wish I knew how to apply lt spice. Anyhow, looks like you changed R1 from 150 to 330 ohms, which should move the low pass cut off from 10,610 hz down to 4,823 hz. That would be the -3db point so the (human ear) noticeable cutoff would be even lower in frequen...

Yes, 1.2 is released, but thus far, with details, only to Sunny. The rest of us must satiate our anticipation with speculation…
all in good time
I guess

Thank you

viewtopic.php?p=3244#p3244
To trouble shoot receive, does help if you have an oscilloscope