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Re: sBITX 64Bit Pi Image Available
#sBitx
On Sun, Mar 2, 2025 at 12:16 AM, <Yo8rc@...> wrote:
A diagram ( documentation ) of mounting the INA260 Power Sensor thanks
The 3D STL mount file and wiring diagram is on our Discord server :)
|
Re: Error starting sBitx v4.3 64 bits
The file to verify is in /boot/firmware.? It is config.txt.? Attached is a copy that works for me:
?
73
Evan
AC9TU?
|
Re: Error starting sBitx v4.3 64 bits
Thanks Evan,
so far I have not been able to disable vc4hdmi0 and vc4hdmi1. how did you do it?
?
?
pi@sbitx:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
? Subdevices: 1/1
? Subdevice #0: subdevice #0
card 1: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
? Subdevices: 1/1
? Subdevice #0: subdevice #0
card 2: audioinjectorpi [audioinjector-pi-soundcard], device 0: AudioInjector audio wm8731-hifi-0 [AudioInjector audio wm8731-hifi-0]
? Subdevices: 1/1
? Subdevice #0: subdevice #0
?
搁补尘ó苍
?
|
Re: How to ruggedize the sBitx V3
My last sad experience shows that a possible extension could be a temperature sensor (with range up to 150 or 200 Celsius) placed on the heatsink near to MOSFET. The software could then limit or swich of power in case of too high temperature.
?
73,
Wojtek SP5DAA
|
Re: sBITX 64Bit Pi Image Available
#sBitx
JJ-
Excellent work on the improvements with V4.4. CW is much more responsive and the full spectrum option (elimination of the decoder screen) is absolutely SUPER!?
It could be made even better with a small correction: The second screen shot that you provided (the one illustrating CW mode operation on 14.065 MHz) is a fine example: Note the received signal appears near the 65.8 label? If you change the mode to CWR then you will see it jump down to about 64.3. The signal did not change frequency, the label did.
?
Generate a signal on 14.065.000 just to confirm it. The spectrum display will be improperly labeled the same way.?
?
Not a feature. The sole reason for the frequency label is to identify the frequency of the signal being displayed at that position. Anything else is misleading and adds confusion. Excluding the pitch variable from the spectrum frequency label generation algorithm would correct that.
?
A minor issue, indeed! The operating system upgrade method is GENIUS. Simple and fast (for the user, at least). Having a computer and internet browser built into the transceiver makes all the difference.
?
We CW operators thank you!!
|
Re: sBITX 64Bit Pi Image Available
#sBitx
A diagram ( documentation ) of mounting the INA260 Power Sensor thanks
|
Re: sBITX 64Bit Pi Image Available
#sBitx
|
I already ordered AlN insulators from Aliexpress. They should arrive in two weeks.
?
73,
Wojtek SP5DAA
?
|
That’s great news! I would strongly suggest switching to the aluminum nitride insulators
Gordon kx4z
toggle quoted message
Show quoted text
On Mar 1, 2025, at 19:13, WZab - SP5DAA via groups.io <wzab01@...> wrote:
? Yes! Replacing the MOSFETs fixed my sBitx v3.
So I have learned two lessons:
- Running continuously in FT8 mode requires either reducing DRIVE or using a fan to improve cooling MOSFETs (especially if running at 13,8V power supply voltage).
- MOSFETs failure due to overheat do not necessarily cause shorting drain to source.
Thanks a lot to all who helped me to isolate and fix the problem.
?
73,
Wojtek
|
Yep, at least I had a bit of foresight and ordered a few more pairs of IRF510s. I'm going to pick it up again tomorrow. I've found that in cases like this, more than a few hours and I start to get frustrated and more likely to cause myself more
problems!
?Thanks for the input and I will keep you posted!
toggle quoted message
Show quoted text
-------- Original message --------
From: "Gordon Gibby KX4Z via groups.io" <docvacuumtubes@...>
Date: 3/1/25 6:52 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
So typically what you do there is unsolder the drain on each MOSFET and just disconnect it so that you can stop those from potentially taking all the current and then see if you still have the direct short
You have to keep working at it until you find out where the current is going, slick tricks like looking for which traces are hot or which voltages are low might help
On Mar 1, 2025, at 18:43, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
|
On Mar 1, 2025, at 18:38, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
?Well, the reverse voltage or whatever happened might have fried the MOSFETS?
On Mar 1, 2025, at 18:27, Michael Bales via groups.io <mikebales73@...> wrote:
?
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
--
Mike - K8MCB?
--
Mike - K8MCB?
Yes! Replacing the MOSFETs fixed my sBitx v3.
So I have learned two lessons:
- Running continuously in FT8 mode requires either reducing DRIVE or using a fan to improve cooling MOSFETs (especially if running at 13,8V power supply voltage).
- MOSFETs failure due to overheat do not necessarily cause shorting drain to source.
Thanks a lot to all who helped me to isolate and fix the problem.
?
73,
Wojtek
|
So typically what you do there is unsolder the drain on each MOSFET and just disconnect it so that you can stop those from potentially taking all the current and then see if you still have the direct short
You have to keep working at it until you find out where the current is going, slick tricks like looking for which traces are hot or which voltages are low might help
toggle quoted message
Show quoted text
On Mar 1, 2025, at 18:43, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
|
On Mar 1, 2025, at 18:38, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
?
Well, the reverse voltage or whatever happened might have fried the MOSFETS?
On Mar 1, 2025, at 18:27, Michael Bales via groups.io <mikebales73@...> wrote:
?
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
|
toggle quoted message
Show quoted text
On Mar 1, 2025, at 18:38, Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> wrote:
?
Well, the reverse voltage or whatever happened might have fried the MOSFETS?
On Mar 1, 2025, at 18:27, Michael Bales via groups.io <mikebales73@...> wrote:
?
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73=
[email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
--
Mike - K8MCB?
Well, the reverse voltage or whatever happened might have fried the MOSFETS?
toggle quoted message
Show quoted text
On Mar 1, 2025, at 18:27, Michael Bales via groups.io <mikebales73@...> wrote:
?
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73= [email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73= [email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
-- Mike - K8MCB?
|
toggle quoted message
Show quoted text
On Mar 1, 2025, at 18:27, Michael Bales via groups.io <mikebales73@...> wrote:
?
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73= [email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73= [email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
-- Mike - K8MCB?
|
Yes, so I've removed D7, I have a direct short to ground, somewhere. I haven't even thought of plugging a pi into it since this began. Right now, even if I apply only 2-3v, the fat trace running from the main switch then around the edge of the board to the
PA xformer is VERY hot. I don't have a component tester at the moment, to examine whats going on with the individual transistors. Any suggestions are welcome.
toggle quoted message
Show quoted text
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern
Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios.
Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY
LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was
damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else
see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via
<mikebales73= [email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of
the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73= [email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
-- Mike - K8MCB?
|
Gordon - do you have the circuit diagram for that protector?
Gerry Sherman
Sent by the Windows 11 Thunderbird
On 2025-03-01 22:47, Gordon Gibby KX4Z
via groups.io wrote:
toggle quoted message
Show quoted text
If you have a
current limited supply at about 2Amps
OR?
a variable voltage
supply,
Then you could do a
preliminary test after replacing D7 so you again have SOME
reverse polarity protection.? ?We have had MULTIPLE radios
severely damaged by good friends of mine in Northern Florida
by accidentally getting the polarity backwards.? ?It only
takes a blink of an eye.
I use a "wall wart"
that ONLY puts out 12V and can't put out more than 1-2Amps for
initial?testing of some of my radios.
Alternatively, I
have a MFJ power supply that is adjustable.? ??
With the Raspberry
Pi DISCONNECTED, you?can very carefully apply current limited
source, or else use a variable voltage source of about 5V and
see what current flows -- there should?be VERY LITTLE if the
raspberry isn't connected.? ? Then if you can get the voltage
up to 12V without having current more than 1/2 amp or so --
you might be in OK shape.? ? But at that point I would
carefully measure the output of the 5V regulator and see if it
was damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky,
not all the 2n2219s were damaged.? ?By measuring the voltage
across their emitter resistors you can calculate the current
through them annd?see what is happening, or else see which
ones are getting HOT.? ??
On Amazon, there are
multiple sources for 2219a's and they aren't that
expensive.....
One of the things I
try to always put together now,....is some form of
polarit?protection on anything expesnsive that I buy.? ? ?I
built a mosfet protection circuit and did a printed circuit
board which is shared as a project on ?
? Lots in our group have used it.? ? I put it on EVERY radio
down at our EOC becuase?it is SO EASY to damage radios when
people are stressed out or tired.
Let usknow?how it
goes!
Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM
Michael Bales via <mikebales73= [email protected]>
wrote:
Not sure, I must have inadvertently applied
12v somewhere I shouldn't have. Either way, I doubt that I
can check any further damage until I replace D7. Probable
worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael,
how did D7 get damaged?? ?Was reverse polarity applied
to the radio at some point?? ?that would be the most
likely way to damage D7 and it would have serious
impacts on some of the other components, such as the 4
transistors in the driver section.? ?So what do you
know about how D7 got damaged???? it isthere?to
protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at
3:01?PM Michael Bales via
<mikebales73= [email protected]>
wrote:
So, after the diagnosis and repair of the power
group components, Q9,Q10,Q101,R5,R6 (all replaced),
on power up, +12v drops to under 2v and the area
around the Q12-15 group heats up quickly. I did note
that D7 was basically shot, continuity in both
directions. What are my most likely culprits at this
point?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
If you have a current limited supply at about 2Amps
OR?
a variable voltage supply,
Then you could do a preliminary test after replacing D7 so you again have SOME reverse polarity protection.? ?We have had MULTIPLE radios severely damaged by good friends of mine in Northern Florida by accidentally getting the polarity backwards.? ?It only takes a blink of an eye.
I use a "wall wart" that ONLY puts out 12V and can't put out more than 1-2Amps for initial?testing of some of my radios. Alternatively, I have a MFJ power supply that is adjustable.? ??
With the Raspberry Pi DISCONNECTED, you?can very carefully apply current limited source, or else use a variable voltage source of about 5V and see what current flows -- there should?be VERY LITTLE if the raspberry isn't connected.? ? Then if you can get the voltage up to 12V without having current more than 1/2 amp or so -- you might be in OK shape.? ? But at that point I would carefully measure the output of the 5V regulator and see if it was damaged BEFORE CONNECTING ANY RASPBERY?TO IT.
If you are lucky, not all the 2n2219s were damaged.? ?By measuring the voltage across their emitter resistors you can calculate the current through them annd?see what is happening, or else see which ones are getting HOT.? ??
On Amazon, there are multiple sources for 2219a's and they aren't that expensive.....
One of the things I try to always put together now,....is some form of polarit?protection on anything expesnsive that I buy.? ? ?I built a mosfet protection circuit and did a printed circuit board which is shared as a project on ? ? Lots in our group have used it.? ? I put it on EVERY radio down at our EOC becuase?it is SO EASY to damage radios when people are stressed out or tired.
Let usknow?how it goes! Gordon KX4Z
On Sat, Mar 1, 2025 at 5:33?PM Michael Bales via <mikebales73= [email protected]> wrote:
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
-------- Original message --------
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of the
other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73= [email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
--
Mike - K8MCB?
|
Not sure, I must have inadvertently applied 12v somewhere I shouldn't have. Either way, I doubt that I can check any further damage until I replace D7. Probable worst case would be having to drop $40 on new 2n2219s.
toggle quoted message
Show quoted text
-------- Original message --------
From: "Gordon Gibby KX4Z via groups.io" <docvacuumtubes@...>
Date: 3/1/25 5:19 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of the
other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via
<mikebales73= [email protected]> wrote:
So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions.
What are my most likely culprits at this point?
--
Mike - K8MCB?
-- Mike - K8MCB?
|
Michael, how did D7 get damaged?? ?Was reverse polarity applied to the radio at some point?? ?that would be the most likely way to damage D7 and it would have serious impacts on some of the other components, such as the 4 transistors in the driver section.? ?So what do you know about how D7 got damaged???? it isthere?to protect somewhat against?reverse polarity
Gordon?
On Sat, Mar 1, 2025 at 3:01?PM Michael Bales via <mikebales73= [email protected]> wrote: So, after the diagnosis and repair of the power group components, Q9,Q10,Q101,R5,R6 (all replaced), on power up, +12v drops to under 2v and the area around the Q12-15 group heats up quickly. I did note that D7 was basically shot, continuity in both directions. What are my most likely culprits at this point?
--
Mike - K8MCB?
|
Don, ND6T
Kevin