(tr)uSDX Forum

In the meantime I found a second mistake on the brand new RF Board with this TCA9555 circuit.

Port 15 for the 15 m Relais is also complett dead.

There is also all the time 0 voltage .
No puls, to switch the K2 Relais.

Because there is from my point view no possibility to remove the circuit and to get a new TCA9555 device
I think I must stop this nice qrp project .

I am very sad about that, but I do not have any Idea what to do.
hellmuth , df7vx

How about some solder bridges? It is very unlikely that they used half dead chip. Maybe relay problems?
Contact yor seller and return it?
73 gl

Ask in your OV (local ham club) who has hot air soldering equipment.
This chip is very easy to change with this. I did not bother to ask, and invested the 50€ to buy my own....
Good investment in retrospective, as it is now also very easy to relpace ATMEGA Chips and SMT Crystals etc. And a replacement chip is cheap.
Not impossible, but a little harder: It can be changed with normal soldering iron and the right technique. But if you want to try it, try it with sacrificial hardware, because there´s a steap learning courve involved.

73 Manuel; DL2MAN

Ok Manuel, desoldering of the device would be not a problem for me.

The main problem would be to get a new one.

But the good news now: I have ordered today some of this devices called
PCA9555 24 pin SSOP Case from R-S Components .
There is no significant difference in function between TCA9555 and PCA9555.

But it was only possible to order this Circuit as a "Dealer". ( a friend here nearby did it for me)
For privat User / People it was not possible to get this integrated Circuits from R-S Components.
hellmuth , df7vx

PCA9555 and TCA9555 are available in large quantities at mouser....

On my group buy page, and here in the group buy organizer forum there are links where to get what:
https://dl2man.de/1-trusdx-group-buy/
viewtopic.php?t=71
Package needs to be TSSOP24, not SSOP !

73 Manuel, DL2MAN

I tried five pieces of TCA9555, but they didn't work. Maybe the dealer sold me a refurbished product, but I used the same batch of TCA9555 on the DL2 version of the five-band UDSX, and there were successful cases. Later, I replaced the PCA9555 I bought from other dealers. The relay works normally. So I suggest that if you want to replace the 9555, try to replace the PCA9555. Although the TCA9555 is an upgraded version of the PCA9555, from the perspective of use, I think the PCA9555 is better, based on my practice.
73.

Thanks very, very much for all the helpfull infos.

I have ordered:

RS Best.-Nr.: 483-7222 Herst. Teile-Nr.: PCA9555PW,112 Marke: NXP
NXP E/A-Erweiterung, 16-Kanal I2C, SM Bus, TSSOP 24-Pin 400kHz SMD

this Cicuits from RS Components.

What i have heard from Mouser ... Manuel, before I call RS Components
I did a phone call to Mouser.
And there I have heard:
I must pay a special price for small quantities ( very high)
next a high price for Fedex Deliverie
and last but not least something Tax
because the Mouser Gentleman told me , that these circuits are delivered from U.S.
So ... a single Device costs approx. 25,00 or more Euros.

Manuel Thanks for your LINK about Mouser. I will try that if it will be nessesary.
73s hellmuth , df7vx

Once, you exeed 50$, shipping is free. You pay sales Tax in advance, and when I ordered the same day
Reichelt (Germany to Germany) and
Mouser (USA to Germany) -> Mouser won the last 3 times in terms of speed.

Mouser is sometimes a little bit more expensive, but they have almost everything.
For Example: BS170s/wide selection of NP0 Capacitors/Si5351/TCA9555/etc....
If you order at mouser: Order more and stock up.
Then they beat everyone else. At least, that´s what I do.....

My last order was just a few toroids to test. Then I added another 100x BS170´s and I was over the free shipping amount....

73 Manuel; DL2MAN

Good morning to all .
Here the good News: Operation sucsessful
Yesterday Afternoon ( only 22 Hours for delivery) I got the PCA9555 TSSOP parts from RS Components .

Today morning I removed the defect Device from RF Board, cleaning the solderpads, apply some SMD Solder Paste
and soldering the new Device with a very small 12 Volt soldering pencil to the RF Board.
After once agin some cleaning and carefully inspection with a magnifying glass, I startet the nice (tr) uSDX ....and all the Relais at the RF Board now still working .
hellmuth , df7vx