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Blown by nearby transceiver #bitx40help

edufortes@...
 

After doing some tests with the rig, I made the mistake of transmitting near the Bitx40 with an ICOM 725 with a badly isolated tuner,
 
A quick flash, smoke, and the bitx40 that was only on, no antenna connected, died. No more tranmission or power output.
 
What components should I start checking or replacing?

Regards,
Eduardo

 

First hand experience with fireworks! Sorry to hear..

RX working ?

At 11-02-2018, you wrote:
After doing some tests with the rig, I made the mistake of transmitting near the Bitx40 with an ICOM 725 with a badly isolated tuner,

A quick flash, smoke, and the bitx40 that was only on, no antenna connected, died. No more tranmission or power output.

What components should I start checking or replacing?

Regards,
Eduardo

Gordon Gibby
 

Hi Eduardo --- where on the board do you see BURN MARKS?


That would be the best clue.   


I have had both bitX40 and uBitx operating 25-50 feet from 2 WINLINK gateway stations for quite a while now and zero ill effects.....  Perhaps RF got into your power wiring?   You might give us some more clues by telling us:


1.  Does the Raduino display appear normally and still tune frequencies?

2.  Does the receiver still tune stations? (that is, does it receive signals from an antenna?)

3.  Does the receiver still have the normal "birdies" if it doesn't receive normal signals?

4.  If you operate a 2nd receiver nearby, do you hear ANYTHING froom your own transmitted signal?

5.  Were you operating with a FUSE and if so, did the fuse blow?



From: BITX20@groups.io <BITX20@groups.io> on behalf of edufortes@... <edufortes@...>
Sent: Saturday, February 10, 2018 9:26 PM
To: BITX20@groups.io
Subject: [BITX20] Blown by nearby transceiver #bitx40help
 
After doing some tests with the rig, I made the mistake of transmitting near the Bitx40 with an ICOM 725 with a badly isolated tuner,
 
A quick flash, smoke, and the bitx40 that was only on, no antenna connected, died. No more tranmission or power output.
 
What components should I start checking or replacing?

Regards,
Eduardo

edufortes@...
 

Thanks for your quick response!
 
The Raduino is intact, tunes but not hearing too much at the moment.
 
Normal clicks are heard when the tuning pot is moved, and carriers are heard. I tried to transmit close with a Pixie (1w) and it is not heard.
 
Find below attached photos where was the spark and seems to be burned the track


chris gress <Chrisg0wfh@...>
 

Looks like you have had rf from the other radio connect antenna wire to c6 see if you can  receive any think that will test q1 is OK if yes replace burnt tracks near L3/L2 check c4/c5 not shorted if you did back to back diodes at k1 replace diodes they will be bad once RX is fixed if no tx replace q13 it will be bad hope this helps chris

On 11 Feb 2018 14:56, <edufortes@...> wrote:
Thanks for your quick response!
 
The Raduino is intact, tunes but not hearing too much at the moment.
 
Normal clicks are heard when the tuning pot is moved, and carriers are heard. I tried to transmit close with a Pixie (1w) and it is not heard.
 
Find below attached photos where was the spark and seems to be burned the track



Gordon Gibby
 

Looks like L3, and possibly other series elements in the 40 m filter got way too much voltage. You’ll probably have to use an ohmmeter to test out each connection and see what has become non-conductive.  I suspect Q 13 got fried in the process, and there are two other transistors that would’ve been connected that might’ve been damaged as well from the schematic.  With some care, these can be replaced by ordinary 2N3904 transistors.

Thank you for showing that picture, it is quite impressive.


On Feb 11, 2018, at 09:56, "edufortes@..." <edufortes@...> wrote:

Thanks for your quick response!
 
The Raduino is intact, tunes but not hearing too much at the moment.
 
Normal clicks are heard when the tuning pot is moved, and carriers are heard. I tried to transmit close with a Pixie (1w) and it is not heard.
 
Find below attached photos where was the spark and seems to be burned the track


<IMG_20180211_114534.jpg>

Jerry Gaffke
 

From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened.
That node is isolated from other parts of the rig that might have significant DC power by multiple DC blocking caps.
RF power there should be milliwatts, even with a nearby QRO transmitter.
Even a loose wire with +12VDC on it striking that node would not blow the trace since there is no path to ground.
L3 is a toroid and thus inherently well shielded, I doubt significant RF was coupled directly into L3 somehow.

Could be that all you need to do is fix the trace.
But the cause is totally unexplained, and something with enough power to scorch a trace like that has enough power 
to blow out many other things.  Fixing this might require finding somebody with a scope and bag of spare parts.

Do let us know what parts had to be replaced once you get this fixed.
And any guesses as to how it happened.
For me at least, truly a mystery.

Jerry, KE7ER


On Sun, Feb 11, 2018 at 08:41 am, Gordon Gibby wrote:
Looks like L3, and possibly other series elements in the 40 m filter got way too much voltage. You’ll probably have to use an ohmmeter to test out each connection and see what has become non-conductive.  I suspect Q 13 got fried in the process, and there are two other transistors that would’ve been connected that might’ve been damaged as well from the schematic.  With some care, these can be replaced by ordinary 2N3904 transistors.
 

Joe Puma
 

Hey Jerry, I’ve had strange things like his happen to me with other equipment when transmitting even with a little Power like the bitx40.  I’ve zapped the inductors on a SpyVerter and SV1AFN upconverter, fried them completely, the spyverter has board damage too but nothing else, no other components. Heck, I’ve fried the SV1AFN a few times with my 100w radio and finally beyond repair because it killed the mixer and too many things I didn’t have parts for.  My SDR Antenna is near my long wire TX antenna I use for my Yaesu and the bitx40 when I had it. 

It happened mostly when I was tuning up, actually I think only when tuning up. And especially on 160. I’ve watched an inductor burn up right before my eyes when the tuner was chattering. Must of been throwing high voltages everywhere. RF sure is amazing lol. I’m still learning. 


Joe
KD2NFC 


On Feb 11, 2018, at 4:34 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened.
That node is isolated from other parts of the rig that might have significant DC power by multiple DC blocking caps.
RF power there should be milliwatts, even with a nearby QRO transmitter.
Even a loose wire with +12VDC on it striking that node would not blow the trace since there is no path to ground.
L3 is a toroid and thus inherently well shielded, I doubt significant RF was coupled directly into L3 somehow.

Could be that all you need to do is fix the trace.
But the cause is totally unexplained, and something with enough power to scorch a trace like that has enough power 
to blow out many other things.  Fixing this might require finding somebody with a scope and bag of spare parts.

Do let us know what parts had to be replaced once you get this fixed.
And any guesses as to how it happened.
For me at least, truly a mystery.

Jerry, KE7ER

On Sun, Feb 11, 2018 at 08:41 am, Gordon Gibby wrote:
Looks like L3, and possibly other series elements in the 40 m filter got way too much voltage. You’ll probably have to use an ohmmeter to test out each connection and see what has become non-conductive.  I suspect Q 13 got fried in the process, and there are two other transistors that would’ve been connected that might’ve been damaged as well from the schematic.  With some care, these can be replaced by ordinary 2N3904 transistors.
 

Jerry Gaffke
 

Something like an airwound solenoid inductor will indeed pick up nearby RF
through magnetic coupling, perhaps enough to burn traces.   

I'd be surprised if a toroid could do that, at least with the fields we normally deal with.
A toroid has a circular field confined mostly to the donut shaped core, a magnetic field
from a nearby device would have little effect because coupling into one side of the toroid
would be nearly balanced out by coupling into the opposite side of the toroid.
On that opposite side, the toroid's internal magnetic field is pointed in the opposite direction,
but the relatively large field from your nearby equipment would be uniform across the toroid.

So does not seem likely to me.
But then I am often surprised.

Jerry


On Sun, Feb 11, 2018 at 02:38 pm, Joe Puma wrote:
Hey Jerry, I’ve had strange things like his happen to me with other equipment when transmitting even with a little Power like the bitx40.  I’ve zapped the inductors on a SpyVerter and SV1AFN upconverter, fried them completely, the spyverter has board damage too but nothing else, no other components. Heck, I’ve fried the SV1AFN a few times with my 100w radio and finally beyond repair because it killed the mixer and too many things I didn’t have parts for.  My SDR Antenna is near my long wire TX antenna I use for my Yaesu and the bitx40 when I had it. 
 
It happened mostly when I was tuning up, actually I think only when tuning up. And especially on 160. I’ve watched an inductor burn up right before my eyes when the tuner was chattering. Must of been throwing high voltages everywhere. RF sure is amazing lol. I’m still learning. 
 
 

 

Very mysterious, looks like ball lightening.

I have seen one right outside my shack window and it was a real treat!

Raj

At 12-02-2018, you wrote:
From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened

Do let us know what parts had to be replaced once you get this fixed.
And any guesses as to how it happened.
For me at least, truly a mystery.

Jerry, KE7ER

 

Jerry,

Looks the L and C formed a series resonant circuit at the transmitted frequency.

Raj

At 12-02-2018, you wrote:
From the photo, looks like a burned trace from C6 to L3.
From the Bitx40 schematic it's hard to imagine how that might have happened.

Jerry Gaffke
 

Possible.

Do we know what the transmitted frequency was?  Was it 40m?
I figure the series loop of L3,C6,C7,C5 to be resonant at 7.45mhz,
    C-total-in-pf = 1/(1/1000 + 1/470 + 1/100) = 76pf
    F-resonance =  1/(2*pi*sqrt(L*C)) = 1/(6.28*sqrt(76e-12 * 6e-6)) = 7.46mhz
Loading from C4,C11,C41 will likely bring that down a bit in frequency.

I'd be looking at the base and emitter DC voltages of Q1 (during receive) and,Q13 (during transmit)
to see if they got blown.  Compare to Randy's chart as previously suggested by Marco: 
    https://groups.io/g/BITX20/files/K7AGE/BITX40%20Voltage%20Measurments.pdf
If  Q1 got blown, then also check Q4.

I am still quite surprised that enough energy got coupled in to blow the trace. 
The traces do form a moderately large loop, a single turn inductor, perhaps that was all it took.
Or perhaps those toroids are not as self shielding as I had figured.

Jerry, KE7ER


On Sun, Feb 11, 2018 at 08:27 pm, Raj vu2zap wrote:
Looks the L and C formed a series resonant circuit at the transmitted frequency.

edufortes@...
 

Thanks to everyone for your help, I'll be checking those and trying to replace the burned components.

 Jerry Gaffke
 (KE7ER),

yes, we were testing 40m on a ICom IC-725. 

I've found another two burned :/    R131 & R132




Jerry Gaffke
 

Those with plastic cases for their Bitx40/uBitx and with nearby high power gear
might line the inside of that case with tinfoil.  Fashion a hat with any leftover scraps.
Jerry, KE7ER


On Sun, Feb 11, 2018 at 09:17 pm, Jerry Gaffke wrote:
I am still quite surprised that enough energy got coupled in to blow the trace. 
The traces do form a moderately large loop, a single turn inductor, perhaps that was all it took.
Or perhaps those toroids are not as self shielding as I had figured.

Jack, W8TEE
 

Fashion a hat with any leftover scraps.
Uncalled for...

Jack, W8TEE


From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: BITX20@groups.io
Sent: Monday, February 12, 2018 10:22 AM
Subject: Re: [BITX20] Blown by nearby transceiver #bitx40help

Those with plastic cases for their Bitx40/uBitx and with nearby high power gear
might line the inside of that case with tinfoil.  Fashion a hat with any leftover scraps.
Jerry, KE7ER


On Sun, Feb 11, 2018 at 09:17 pm, Jerry Gaffke wrote:
I am still quite surprised that enough energy got coupled in to blow the trace. 
The traces do form a moderately large loop, a single turn inductor, perhaps that was all it took.
Or perhaps those toroids are not as self shielding as I had figured.


Gordon Gibby
 

Hi Jack, I hope your response was in jest!

I once gave a four session training package on financial planning to the docs at my institution and I told them the last session would be way off the beaten path, and I actually made a tin hat to wear to start off that session. As usual, my predictions turned out to be mostly completely wrong so far.  Luckily, I never completely believe even myself.


On Feb 12, 2018, at 10:24, Jack Purdum via Groups.Io <jjpurdum@...> wrote:

Fashion a hat with any leftover scraps.
Uncalled for...

Jack, W8TEE


From: Jerry Gaffke via Groups.Io <jgaffke@...>
To: BITX20@groups.io
Sent: Monday, February 12, 2018 10:22 AM
Subject: Re: [BITX20] Blown by nearby transceiver #bitx40help

Those with plastic cases for their Bitx40/uBitx and with nearby high power gear
might line the inside of that case with tinfoil.  Fashion a hat with any leftover scraps.
Jerry, KE7ER


On Sun, Feb 11, 2018 at 09:17 pm, Jerry Gaffke wrote:
I am still quite surprised that enough energy got coupled in to blow the trace. 
The traces do form a moderately large loop, a single turn inductor, perhaps that was all it took.
Or perhaps those toroids are not as self shielding as I had figured.


Jerry Gaffke
 

Very curious. 
Blowing R131 and R132 might be due to a very large signal showing up at Q13,
though I would expect Q13 to blow first.

In your first post it says:
    > A quick flash, smoke, and the bitx40 that was only on, no antenna connected, died. 
I would think the Bitx40 would have to be in transmit to supply +12v via the TX rail
for R131,R132 to fry.  Perhaps the RF field also managed to turn on PTT somehow?

I find this to be very weird and still unexplained, we appreciate all the photos.
Another photo showing the tuner involved and the physical placement of transceiver, tuner, and Bitx40
would be appreciated.  Also any further information about what was going on when this occurred.

Jerry, KE7ER




On Mon, Feb 12, 2018 at 07:18 am, <edufortes@...> wrote:

I've found another two burned :/    R131 & R132

Jerry Gaffke
 

When bored with all the cat videos, take a look at this:
    https://www.youtube.com/watch?v=urglg3WimHA
Weird Al rules!

Jerry, KE7ER


On Mon, Feb 12, 2018 at 07:27 am, Gordon Gibby wrote:
Hi Jack, I hope your response was in jest!
 

chris gress <Chrisg0wfh@...>
 

My guess is he made a mistake and the 725 was wired to the bitx via coax and atu the poor bitx got a big dose of rf it can be fixed 

On 12 Feb 2018 15:37, "Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

Very curious. 
Blowing R131 and R132 might be due to a very large signal showing up at Q13,
though I would expect Q13 to blow first.

In your first post it says:
    > A quick flash, smoke, and the bitx40 that was only on, no antenna connected, died. 
I would think the Bitx40 would have to be in transmit to supply +12v via the TX rail
for R131,R132 to fry.  Perhaps the RF field also managed to turn on PTT somehow?

I find this to be very weird and still unexplained, we appreciate all the photos.
Another photo showing the tuner involved and the physical placement of transceiver, tuner, and Bitx40
would be appreciated.  Also any further information about what was going on when this occurred.

Jerry, KE7ER




On Mon, Feb 12, 2018 at 07:18 am, <edufortes@...> wrote:

I've found another two burned :/    R131 & R132

Lawrence Galea
 

Looks like C131 has also flashed. There is a dark area as if has burned.

On Mon, Feb 12, 2018 at 4:18 PM, <edufortes@...> wrote:
Thanks to everyone for your help, I'll be checking those and trying to replace the burned components.

 Jerry Gaffke
 (KE7ER),

yes, we were testing 40m on a ICom IC-725. 

I've found another two burned :/    R131 & R132