reviving my sbitx v3

Michael Bales All Messages By This Member #116026 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?
Gordon Gibby KX4Z All Messages By This Member #116027 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? toggle quoted message Show quoted text 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?
Michael Bales All Messages By This Member #116028 开云体育 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) To: [email protected] 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?
Gordon Gibby KX4Z All Messages By This Member #116029 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 toggle quoted message Show quoted text 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 -------- From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]> Date: 3/1/25 5:19 PM (GMT-05:00) To: [email protected] 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?
Gerald Sherman All Messages By This Member #116030 开云体育 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 -------- From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]> Date: 3/1/25 5:19 PM (GMT-05:00) To: [email protected] 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 Bales All Messages By This Member #116031 开云体育 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 From: [email protected] <[email protected]> on behalf of Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> Sent: Saturday, March 1, 2025 3:47 PM To: [email protected] <[email protected]> Subject: Re: [BITX20] reviving my sbitx v3 ? 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 -------- From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]> Date: 3/1/25 5:19 PM (GMT-05:00) To: [email protected] 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 Gibby KX4Z All Messages By This Member #116032 开云体育 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. From: [email protected] <[email protected]> on behalf of Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> Sent: Saturday, March 1, 2025 3:47 PM To: [email protected] <[email protected]> Subject: Re: [BITX20] reviving my sbitx v3 ? 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 -------- From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]> Date: 3/1/25 5:19 PM (GMT-05:00) To: [email protected] 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 Gibby KX4Z All Messages By This Member #116033 开云体育 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. From: [email protected] <[email protected]> on behalf of Gordon Gibby KX4Z via groups.io <docvacuumtubes@...> Sent: Saturday, March 1, 2025 3:47 PM To: [email protected] <[email protected]> Subject: Re: [BITX20] reviving my sbitx v3 ? 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 -------- From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]> Date: 3/1/25 5:19 PM (GMT-05:00) To: [email protected] 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 Gibby KX4Z All Messages By This Member #116034 开云体育

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.

From: [email protected] <[email protected]> on behalf of Gordon Gibby KX4Z via groups.io <docvacuumtubes@...>
Sent: Saturday, March 1, 2025 3:47 PM
To: [email protected] <[email protected]>
Subject: Re: [BITX20] reviving my sbitx v3
?

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 --------

From: "Gordon Gibby KX4Z via " <docvacuumtubes=[email protected]>

Date: 3/1/25 5:19 PM (GMT-05:00)

To: [email protected]

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?