(tr)uSDX Forum

Hello Ralph dl1bax,
there is no shame. I can help you and would solder the 3 components onto the circuit boards for free.
It would be good, if you would then take over the shipping costs for sending it back and forth.

Maybe there is another German OM who can help you in your area

Please send me an email to dl9tx(ät)darc.de

We are Radio Amateur and we help each other

73 Stefan

Hello Stefan.

That's a great offer, which I'm very happy to accept.
Everything else then by mail.

I ask all interested parties, who have written to me, to understand that I would like to use the (tr)sdx myself thanks to Stefan's help.

Many greetings
Ralph

Dear Adam,
The kits arrived a few days ago. Thank you very much for your huge efforts for organising it!

73! Marian

Greetings to all ham craftsmen!
TRX is already running in, I'm out of the packaging and I'm waiting for adjustment and tuning work. Advice for everyone, it is necessary to solder very carefully, I had a bad connection at the display, at first it looked like a bad ATmega, but after repairing the power supply, the display lit up and showed an 18-digit serial number, then I downloaded the firmware and after installation ran.
I keep my fingers crossed for everyone and I wish you a lot of fun.
Hi Jirka OK2JIQ VY73!

Received my kit a few days ago, thanks again Adam!

Luckily a fellow ham spotted a loose capacitor (C9) before I put everything together.

When I first powered it up with 12V, the PA went up in smoke. But I guess that's my fault and not connected to the capacitor. Happy soldering all!

Hello folks,
I have important information here. The BS170 transistors must not be installed in the position specified in the circuit diagram on the circuit board. They must be installed rotated by 180 degrees!

If this is not observed, the output stage transistors will short-circuit until they burn out. The device cannot be switched on, you will notice it when the display stays off.

It probably affects everyone in group 1 and ?, I don't know who else.

For this reason, before you solder the BS170, check where the source, drain and gate are!

Thank you!

hi i checked the 3 fets in my kit.

indeed i have also to turn the fets (drain and source are inverted)


thanks for this info

73 jean-marie on7en
www.on7en.be

Thank you for the solution! I will put in new ones the right way round.

Where did you source your BS170? The RF Board BOM specified BS170-D74Z, which has Drain - Source -Gate, which also would be incorrect (I think).

The BS170's I bought from Kits and Parts has Drain - Gate - Source, which was only blind luck on my part...

https://kitsandparts.com/BS170.pdf

BS170 are sourced from China (aliexpress). Unfortunately, supplier had very minimal description >> https://www.aliexpress.com/item/4001126097914.html
I will check them in the evening, but I assume all are the same (sourced in bulk.)

Dear All,
please post me a message that kits are delivered.
One clarification (cause got some questions): copper wire (0.4mm) was not included in the package. It is lessons learnt before group #2 purchase to include it as well.

73,
Adam SN3AK

indeed the pinout is like in 2N7000 (http://www.datasheetcafe.com/2n7000-pin ... ransistor/)
So, connecting like silkscreen layer show on PCB ends up with firing transistor's internal diode means whole element

Thank you for the advice Adam.
Will go home tomorrow and will check the kit.

Just as a remark:
This is NOT bad Layout, it´s just the wrong FETs.
So Putting the FETs in Reverse is NOT a general Advise. This is only a workaround for those who were supplied by the group buy with the FETs with reversed Polarity !!!

Bottom Line in General:
Make sure, you buy the right FETS !

73 Manuel; DL2MAN

How to make sure?
I bought from several places. All of them are the same. They probably have the same source.
In the end, correct identification solves the problem.

yo8rcd wrote: ↑06 Apr 2022, 11:23 How to make sure?

Well then let´s have a look what the creator wrote, shall we ?
We go to https://dl2man.de/1-trusdx-group-buy/
Scroll down the page to the Section of Part Sources: Then let´s click the link:
https://www.mouser.de/ProductDetail/512-BS170_D74Z
Oh Noooo.... Not available, so let´s click on the Datasheet to see what it should be like: and immediately, we see the correct Pin-Out:
FALSE And this myteriously matches the PCB layout....

yo8rcd wrote: ↑06 Apr 2022, 11:23 correct identification solves the problem.

Absolutely right.... If you buy from another source, make sure, you get the same stuff as it was created for.....

EDIT:
I added a warning to my page to watch for the right polarity....

73 Manuel; DL2MAN

Thanks for the explanations Manuel!
Personally, I still haven't gotten to burn semiconductors on the (tr) uSDX board. I know from previous projects this problem with BS170 transistors.

Health and success in everything you do!

Thanks Manuel for the comment. For sure it is not design issue.
For me it is a lesson learnt to check things even if it seems it should be no issue. BS170, TO92 - until now, I cannot imagine it might have different pinout depending on the source.
Have a good day,
Adam SN3AK

Sorry, I am a bit confused. The BS170 in our kit seems to have a pinout of SGD. The pinout in the onsemi datasheet for the BS170 says DSG for the pinout. Is it really DSG or shouldn't it be DGS?

Wow, what a mess. Appparently there are at least three variants of BS170 pinout on the market but all of them are called BS170. What a betrayal by the semiconductor manufacturers.

To DF6MZ:
Manuel's design calls for DSG. Edit2: Or maybe not, see the post below. Pin 3 is grounded.

According to the circuit diagram, source is still grounded. Or am I wrong? It can not be the middle pin.

Edit: Must be in my opinion:

Also when our "old" BS170 with SGD work when soldered 180°, then it should be DGS right?

Oh my gosh! I'm using this, My BS170 type is DGS but according to Manuel's answer, I think my transistor is wrong. Is that why the maximum power could not exceed 3W?

Can someone tell me which is pin1 of the LT6231? There appears to be no marker and data sheets don’t help.

It should be DGS, in my opinion. Also, there is a very minor error on the RF Board, because the Source is grounded, the pin hole should be square. Currently, the Drain hole is square.

sorry to be pedantic...