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any hints on replacing V2 board with V3 ????

bill steffey NY9H
 

expecting a board ( to get current ) ..... got tired of having to pay attention to all the conversations on mods....

guess I'm 50% appliance operator & DXer.

so you have any hints? , should be easy//

bill

On 7/23/2023 1:35 PM, Evan Hand wrote:
Hi Steve,

I agree that changing to the aluminum nitride insulators should remove any issue with the heat on the finals.? I do not see a fan as required at this time.? My comments pointed out that the full scope of the thermal process needs to be addressed, not just the insulators.

Looking at your thermal pictures, it appears that you have a DE without all of the mods to the PA completed.? I also noted that Q13 is much warmer than the other three pre-driver transistors. You might want to look into that before a failure.

Just suggestions.
73
Evan
AC9TU
 

Hi Bill,
?
To answer your question, just take the V2 board out and install the V3 board in it's place. They are basically identical boards, the V3 board having IRF510s for finals instead of the original IRFZ24Ns. The V3 board also has the clamping diodes across the gates of the IRF510s to protect them from voltage spikes blowing them up, other than that there isn't much difference. I upgraded my V2 board to a V3, I then modified my V2 board and i keep it as a spare but have never needed it.
?
Joel
N6ALT
bill steffey NY9H
 

tnx Joel , that sound like my plan...

? ? what are the specs on the diodes used for clamping..????

On 9/23/2024 10:25 AM, Joel Caulkins/N6ALT wrote:
Hi Bill,
To answer your question, just take the V2 board out and install the V3 board in it's place. They are basically identical boards, the V3 board having IRF510s for finals instead of the original IRFZ24Ns. The V3 board also has the clamping diodes across the gates of the IRF510s to protect them from voltage spikes blowing them up, other than that there isn't much difference. I upgraded my V2 board to a V3, I then modified my V2 board and i keep it as a spare but have never needed it.
Joel
N6ALT
--
link to my QRZ listing

 

Hey Bill,
?
One other thing I forgot to mention, you will have to move your Raspberry Pi over from the V2 board to the V3 board but that's easy, just four screws, also make sure to install the SD card that comes with your new V3 board in the Raspberry Pi, don't use the the V2 SD card on the V3 board.
?
Joel
N6ALT
 

Bill,
?
Here is link to the TVS diodes,
?
Joel
N6ALT
 

I replaced my V2 with a V3 board.?? Moved the Pi4 over and used the new SD card.? Works great except for the V3 SWR not really reading.? I replaced the finals ( 4th time ) in my old V2 board with the IRF 510's and installed an old Pi 3B on it and now have a second sBitx that works great also!
 

On Tue, Sep 24, 2024 at 03:57 AM, Michael Saladino wrote:
I replaced my V2 with a V3 board.?? Moved the Pi4 over and used the new SD card.? Works great except for the V3 SWR not really reading.? I replaced the finals ( 4th time ) in my old V2 board with the IRF 510's and installed an old Pi 3B on it and now have a second sBitx that works great also!
Michael,
could you tell the forum readers why the final stage fets had to be replaced 4 times?
What antenna, what power supply did you use and in what modes did you use the device so that this could happen?
We want to learn from others' descriptions to avoid similar stories.
--
Gyula HA3HZ
 

Sure Gyula, ? original finals in the V2 were an issue. ?Had an initial failure running FT-8 on 10m at about 50% power. ? At the time the power supply was a 30A non current limited unit. ?I replaced the finals with original FET version twice and failed them trying to set bias. ?Upon the last failure I got a current limited supply per your comments and used the IRF 510s.?
V2 board has been stable running the IRF 510s and a current limited power supply set to about 6A. ?

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