new problem with my (tr)uSDX

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peppone
 

Posts: 24
Joined: 05 Aug 2022, 09:16

new problem with my (tr)uSDX

Post by peppone »

hi, i soldered 3 new bs170 becouse my radio was showing NO POWER in the screen when i wass pressing ptt or key (CW mode), but now when i connect rf board on mainboard this do not go on, vice-versa if i disconnect rf board the mainboard go on normally...what can be the problem? before the radio was very good in RX
relistan
 

Posts: 38
Joined: 23 Jun 2022, 12:12

Re: new problem with my (tr)uSDX

Post by relistan »

Sounds like a short, possibly on the solder work you did. Double check your pinouts and also that you did not bridge any solder joints.
EI9ITB / KB8SWH
peppone
 

Posts: 24
Joined: 05 Aug 2022, 09:16

Re: new problem with my (tr)uSDX

Post by peppone »

thanks, i will check it
EDIT: i checked it , no short on soldering...the old mosfet was BS170-E52, the new mosfet are BS170-QG95, are this the same? the only thing i changed are the 3 BS170 and now mainboard don't go ON with rf board connected
DL2MAN
 

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Joined: 30 Dec 2021, 19:18
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Re: new problem with my (tr)uSDX

Post by DL2MAN »

Please check with a component Tester, that your new BS170´s have the same Pin Layout as the old one.
There seem to be 2 Pin-Layouts. In case you have the wrong one, the FET´s are in Reverse now, and the Internal Diodes are shorting your DC to GND as soon as RF Board is connected.

From the https://dl2man.de/1-trusdx-group-buy/ page:
BS170-ATT.JPG
BS170-ATT.JPG (25.98 KiB) Viewed 1010 times
73 Manuel; DL2MAN
peppone
 

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Joined: 05 Aug 2022, 09:16

Re: new problem with my (tr)uSDX

Post by peppone »

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Last edited by peppone on 07 Sep 2022, 13:50, edited 5 times in total.
DL2MAN
 

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Re: new problem with my (tr)uSDX

Post by DL2MAN »

peppone wrote: 07 Sep 2022, 11:34 in the picture there is the right bs170 pinout?
Yes
peppone
 

Posts: 24
Joined: 05 Aug 2022, 09:16

Re: new problem with my (tr)uSDX

Post by peppone »

in my new bs170 drain and source are inverted, the gate is correct...
so can I mount other new 3 bs170 inverted or are not good?

EDIT: i watched how to test a mosfet with a tester in diode mode, positive on drain and negative on source no conduction (this is ok on my bs170 ) after he disconnect positive, touch gate with positive and reconnect it on drain and he has conduction between D and S becopuse opened the G... i have not this result with my bs170, it is right or i have not a bs170 but a fake???

EDIT: i mounted 3 new BS 170 inverted, now the radio go on with RF board connected, next step is to search for a dummy load to test it in TX
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