Re: plastic under finals? #sBITX_v3

#111078

Depending on circuit design and pin layout, it is often necessary to insulate the flat back metallic side of transistors from ground. This used to be done with thin sheets of mica with heat sink compound. Now many applications will use manufactured insulators such as silicon, or such. The idea is to transfer heat, but not be electrically connected. I would say that if the insulators were found in place, install the new transistors with them in place. I would verify isolation with an ohm meter also. Otherwise,? you may get unwanted smoke escaping from other components.

Scotty WD4PYT?

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On Fri, May 10, 2024, 7:36 PM Jeff Duce via <jefe_de_estado=[email protected]> wrote:

Is there supposed to be a piece of plastic between the IRF510s and the heatsink? (The smaller oval shaped piece.)

Re: plastic under finals? #sBITX_v3

#111077

I believe so, mine has that as well
--
'72

Aaron?

plastic under finals? #sBITX_v3

#111076

Is there supposed to be a piece of plastic between the IRF510s and the heatsink? (The smaller oval shaped piece.)

Re: Sbitx external amp keying

#111075

Yes, that is what I saw. T h a n k? y o u!

Re: Instability Issues #sBitx #sBITX_v3

#111074

Assuming you only have a multimeter, you can try this..

Shorted Pin Check

Set your multimeter to the continuity or diode test mode.
Check for shorts between each pair of pins (Gate-Drain, Gate-Source, Drain-Source).
There should be no continuity between any of the pairs. A beep or low resistance reading indicates a short circuit, and likely a damaged MOSFET.

Resistance Check

Set the multimeter to resistance mode.
Connect the multimeter leads to the Drain and Source pins.
Without applying any voltage to the Gate, the MOSFET should be "OFF", showing high resistance (ideally, it should appear as an open circuit).

?

-JJ

Re: Instability Issues #sBitx #sBITX_v3

#111073

开云体育

Well, unexpected follow up....? I was funning FT8 on 40m last night.? I had JTDX and gridtracker running, but they weren't controlling the radio (mode was set to FT8, not Digital).? So I was watching the maps to get squares that I need.? But then I wasn't getting anyone back at all.? My brother who lives about 20miles away contacted me, and it logged, but halfway through I realized that there was 0W output displayed on the screen.? So I went out to the garage and watched it show that the output is 0, the tuner said something like .1w.? It was only drawing about 1amp current from the power supply on TX.? So it appears I've cooked the finals somehow.? This morning I tested the sense diodes (while still in the pcb, do I need to pull them out first?) and they showed ~.3v forward, and ~1v in reverse.? How do I test the mosfets?

I did run git stash/pull and ./update, but that didn't change anything.?

It looks like it's modulating, on FT8 and 2-Tone testing, but no power is getting out.?

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From: [email protected] <[email protected]> on behalf of Jeff Duce <jefe_de_estado@...>
Sent: Thursday, May 9, 2024 4:19 PM
To: [email protected] <[email protected]>
Subject: Re: [BITX20] Instability Issues #sBitx #sBITX_v3

?

Sounds good, I'll give that a go tonight.?

hmmm.... Actually, you've reminded me of something.? When I export the log to adi and upload to LotW, it complains that one of my entries is ignored due to errors.? I'll have to look at that entry tonight.

From: [email protected] <[email protected]> on behalf of JJ - W9JES <w9jes@...>
Sent: Thursday, May 9, 2024 4:01 PM
To: [email protected] <[email protected]>
Subject: Re: [BITX20] Instability Issues #sBitx #sBITX_v3

?

Jeff,

I had my sBitx log open while operating FT8 mode from sBitx over several days and didn't encounter any issues.?

You may need to perform a git stash and git pull then compile with ./update

There may be an issue with the sqlite database or a file on your local copy.

-JJ

Re: Where is the wsjtx_log.adi file? #sBitx

#111072

I guess I did not explain well. I was looking for the EXPORT button, which as you can see in the screenshot I supplied, is not present. It was referred to earlier in this thread:

Re: Sbitx external amp keying

#111070

You may remember this description:
Adding external relay control two V2/V3
--
Gyula HA3HZ

Re: Sbitx external amp keying

#111069

Would something like this work?

????Keying Adapter (HV Switch)

There is a circuit diagram in the user guide.

-JJ

Re: no transmit sbitx v3

#111068

Have you tried the CW mode and just hitting the PTT button on the mic???

Do that with the DRIVE set to 100.

Do you get anything out then?

Sbitx external amp keying

#111067

Guys, I know I saw some information on keying an external amplifier with the sBitx but I fail to find any information when doing a search. Anyone have that info handy?
TU
Barry
K3BO

Re: Instability Issues #sBitx #sBITX_v3

#111066

开云体育

Sounds good, I'll give that a go tonight.?

hmmm.... Actually, you've reminded me of something.? When I export the log to adi and upload to LotW, it complains that one of my entries is ignored due to errors.? I'll have to look at that entry tonight.

Show quoted text

From: [email protected] <[email protected]> on behalf of JJ - W9JES <w9jes@...>
Sent: Thursday, May 9, 2024 4:01 PM
To: [email protected] <[email protected]>
Subject: Re: [BITX20] Instability Issues #sBitx #sBITX_v3

?

Jeff,

I had my sBitx log open while operating FT8 mode from sBitx over several days and didn't encounter any issues.?

You may need to perform a git stash and git pull then compile with ./update

There may be an issue with the sqlite database or a file on your local copy.

-JJ

Re: Instability Issues #sBitx #sBITX_v3

#111065

Jeff,

I had my sBitx log open while operating FT8 mode from sBitx over several days and didn't encounter any issues.?

You may need to perform a git stash and git pull then compile with ./update

There may be an issue with the sqlite database or a file on your local copy.

-JJ