Re: Sbitx Basic Kit with repairs delivered yet.
HF Signals said they would be delayed, as I recall Ken, N2VIP
toggle quoted message
Show quoted text
On Aug 19, 2022, at 10:56, Robert AG6LK <amrmedic@...> wrote:
?Hello all,
Has anyone received their Sbitx basic kit with the LM338 repaired with the new switching regulator yet?
The reason why I ask is that I ordered my Sbitx basic kit on August 9th and it hasn't shipped yet, I'm wondering if the repair of the Lm338 is holding the shipment up?
Thanks,
Robert AG6LK
|
Sbitx Basic Kit with repairs delivered yet.
Hello all,
Has anyone received their Sbitx basic kit with the LM338 repaired with the new switching regulator yet?
The reason why I ask is that I ordered my Sbitx basic kit on August 9th and it hasn't shipped yet, I'm wondering if the repair of the Lm338 is holding the shipment up?
Thanks,
Robert AG6LK
|
Re: sBitx process no longer starts
Both IRFZ24Ns are shorted. I removed them an tested them with a multimeter as I did with the original pair that blew. I also tested the second pair before swapping them in. (I ordered a set of 10 on Amazon when the first pair blew.) I installed a third set late last night but I¡¯m not going to power it up until I have more time. Interestingly I seemed to have no problem earlier this week using cw. The only thing I changed is to increase the IF value from the default 41 to about 85 since it improved the signal on receive. I know that the uBitx runs transmission through the same chain of amplifiers as the receive function, just in reverse. Could increasing the IF value on the sBitx screen damage the PA MOSFETs?
|
Re: Daylight radio toroids
Dear Barry,
Very verry interesting.?? Sounds to me that coil form is a winner.?? Where did you buy the thread bobbins??? I am in the hunt.?? I am putting a test fixture together today so I can start testing materials.
but you may have hit on the most desirable form for the coils.
Take care and have fun. Thanks for sharing.
73 Dave WA5DJJ
SUPER QRSS GRABBER https:www.qsl.net/wa5djj/
|
Re: #sbitx - an ugprade kit is on the way
#sBitx
On Mon, Aug 15, 2022 at 12:01 AM, Ashhar Farhan wrote:
?
These will go out by Thursday if all is well.
?
?
- f
Will there be any notification they've shipped, and by what method? Not wanting to create any additional work for the HF Signals team, just nice to be able to keep an eye out for the delivery, especially as erratic as my usps delivery can be.
|
Farhan's 2006 Interview on the SolderSmoke Podcast (and 2019 pictures)
BITX fans will like this blast from the past:?
|
|
|
I think the rpi and the display will be protected as they are on the otherside of linear regulators. I would begin by first removing the digital board, disconnecting the display and powering up. Is the short still there?? Next, remove the regulator, I hope it works at that point. - f
On Fri, Aug 19, 2022, 6:29 PM Willi, OE1WKL < willi@...> wrote: Sbitx
|
|
|
Which radio are we talking about?
On Fri, Aug 19, 2022, 5:15 PM Willi, OE1WKL < willi@...> wrote: I made a silly mistake when soldering the power cable, and mixed up polarity... When trying to start it up, it made a bang and the smoke came out.
What is the likely damage? What will need replacement?
Willi
OE1WKL
|
I made a silly mistake when soldering the power cable, and mixed up polarity... When trying to start it up, it made a bang and the smoke came out.
What is the likely damage? What will need replacement?
Willi
OE1WKL
|
Hi Ram¨®n ,
A general question on the Raduino32. My understanding is that the ESP32 is powered by 3V3 (VDD) via an on-board regulator. The specification for the digital IO Vih (max) is VDD + 0.3V. This means the ESP32 IO pins are not 5V tolerant.
I am not sure if there are any devices directly driving 5V on their IO towards the ESP32, but there are a few interfaces which have pull-up resistors to 5V. In the case of the I2C interface, which is also connected to the SI5351, the pull-ups are connected to 3V3, since the SI5351 itself is not 5V tolerant. In this case the interface to the ESP32 should be okay, provided other devices on the I2C bus are not connected with stronger pull-ups connected to 5V.
Hopefully, there are no problems with the implementation on the Raduino32.
?
73,? Dave (G8PTN)
?
|
Re: sBitx process no longer starts
Hi John;
Don't get discouraged. Farhan and this community will help you get it figured out.
I own an sBitx "Developer Edition" to learn about DSP and RF Design. During the learning process, some of the magic smoke is bound to escape. That's when the real learning begins.
Recommend you run a separate wire from?+12 Volts over to the input of U7, so that you can get the receiver back in operation.
Your observation that the trace blew when you hit the PTT sounds important. The FETs were clearly not shorted, or the PC trace would have blown at the moment power was applied. It could be a PA Bias issue, as the bias is only applied during transmit. It could be some kind of oscillation as well.
Can you make some resistance measurements around the FETs to see if they are shorted now?
73; Steve, N3SB
On Thu, Aug 18, 2022 at 7:57 PM John Terrell, N6LN < N6LN@...> wrote: I found the reason for zero voltage to U7: that pc trace vaporized. This was after I repaired it two nights ago. This left the RPi branch intact with power unchanged. I believe this is from a second set of IRFZ24N PA mosfets fried. This happened within a few milliseconds when I pressed the PTT button on the microphone, exactly the same way the first pair blew the other night. I don¡¯t know what to do next.
|
Re: sBitx process no longer starts
My sBITX (#59) has been acting strangely, too, and I think the problem is the supply voltage.? I've taken some measurements at J3 (digi board) with various components attached.
The voltage at J3 without the Pi or touchscreen is 5.40v.
Plug in the Pi (and external HDMI monitor) and the voltage drops to 5.25v (CLI display) and 5.21v (GUI display).
Add the touchscreen and the voltage drops to 5.01v (CLI) and 4.98v (GUI).
Running the sBITX software (GUI) the voltage drops to 4.94v and stays at 4.93-4.94v for several hours.
When the screen blanker kicks in the voltage increases to 5.13v.
Other units may perform better or worse.
The Pi 4 wants 5.2 to 5.4v and misbehaves with lower voltages.? The LM388 can supply the necessary current but R79 and R80 (main board) may need adjusting to supply 5.4v under load.
-73 de Paul? K9MV
|
Re: Daylight radio toroids
I redid my test gig and came up with some interesting figures for the bird cage. The Q was in excess of 300. Series capacitor of 270PF with 28T of 24ga wire. Series resonate frequency approx. 5.9MHZ. L measured around 2.15uf. ? K3BO ? Sent from for Windows ?
toggle quoted message
Show quoted text
From: barry halterman via groups.ioSent: Thursday, August 18, 2022 2:57 PM To: [email protected]Subject: Re: [BITX20] Daylight radio toroids ? I don¡¯t think things are working the way they should OR I am not interpreting the data correctly. I really have not measured Q before with the NanoVNA. The micrometals? core showed a resonance of 13MHZ with a Q of 1000. The bird cage showed a resonance of 28MHZ with a Q in excess of 40,000. Those inductors were just from port1 to ground. Something does not add up:{ I used NanoVNA-saver and my SAA2 to get those figures. 73 K3BO Sent from for Windows ? ? It might be reading it correctly. Try reading a yellow core Micrometals/Amidon toroid for comparison. ? On Thu, Aug 18, 2022, 9:39 PM barry halterman <kthreebo@...> wrote: First attempt to measure Q not too good. 79...My test fixture might not be up to snuff. ? On Thu, Aug 18, 2022, 10:01 AM barry halterman via <kthreebo=[email protected]> wrote: Ashhar, yes I do but never measured Q with either units. Hints? ? On Thu, Aug 18, 2022, 9:39 AM Ashhar Farhan <farhanbox@...> wrote: Barry, Do you have a nanovna or th antuino? You could measure the Q of these easily. ? On Thu, Aug 18, 2022, 6:59 PM barry halterman <kthreebo@...> wrote:   After reading about toroids and the pit falls, I did some experiments using sewing machine bobbins.
The bobbins that I have are JANOME and are 20mm x 10mm with a center hole 6mm. I have attached a few
Pictures of the "bird cage". I have no idea what they are made from but the microwave test did not phase them.
If the losses of toroids is the material, these bobbins are 80 percent air with a little scaffolding to hold the wire.
The "bird cage" has 28turns of 24ga that measured 2.15 uh.
I would appreciate comments, good or bad.
73
Barry
|
Re: sBitx process no longer starts
I found the reason for zero voltage to U7: that pc trace vaporized. This was after I repaired it two nights ago. This left the RPi branch intact with power unchanged. I believe this is from a second set of IRFZ24N PA mosfets fried. This happened within a few milliseconds when I pressed the PTT button on the microphone, exactly the same way the first pair blew the other night. I don¡¯t know what to do next.
|
Re: sBitx process no longer starts
Unless their teacher is in the LICW Club! -- Rich
------ Original message------ From: Gordon Gibby Date: Thu, Aug 18, 2022 6:37 PM Cc: Subject:Re: [BITX20] sBitx process no longer starts
Isn¡¯t it so nice to have open source equipment? ? Makes it so much easier to diagnose.
I cracked this radio open for the first time today to show 4 middle school students, who were reasonably well impressed. ??
Guess what they elected to do the next time or a little ham club meets? ? They want to learn Morse code!
This puzzled me so we talked it over with an education major and she said that students of that age group love secrets. ?If I get them doing Morse code, I bet I can turn them into amateur radio operators eventually. ?They will be so pleased to be able to send secret messages!!
Gordon Gibby.? On Aug 18, 2022, at 18:16, Steve Beckman > wrote:
? Hi John;
The error message you're getting is coming from the i2cbb.c module (so great to have access to the sBitx source code!) That module is generating the error because it's finding the I2C serial data line is at a logic 0 / low voltage level when it should not be. Looking at the sBitx schematic, the Bit-Banged I2C bus communicates with the SI5351 synthesizer chip through pins 39 and 37 of the connector mating the digital daughterboard to the motherboard. Pin 39 is right on the end of the connector, so that's of note and worth a careful look. The SDA and SCL lines have to be pulled high with resistors R1 and R2, both 3.3 K Ohms, or else they can float low and cause this error.
So - possible problems: 1) Pin 39 from the digital board not mating properly with the motherboard - check that the digital board is fully inserted into the motherboard. 2) Regulator U7 on the main board not providing 3.3v to the SI5351 and the two pull-up resistors R1 and R2 3) R1 on the motherboard missing or damaged 4) SI5351 shorted / damaged
Hopefully it's just the mating of the digital daughterboard to the main motherboard - and you'll be back on the air shortly.
73; Steve, N3SB
On Thu, Aug 18, 2022 at 5:56 PM John Terrell, N6LN < N6LN@...> wrote: I also ran raspi-config to make sure i2c was enabled. No change. I get the same error.
|
Re: sBitx process no longer starts
John - I just made a few resistance measurements on my sBitx. With power turned off and disconnected:
?-- Pin 3 of U7 to case of either driver transistor (free-standing transistors with heat sinks) - shorted. Confirms that 12 Volts is getting to U7. ?-- Tab of U7 to Ground - about 2K Ohms.
Regulator U7 is only powering the SI5351 and a 25 MHz oscillator. It's got an easy life!! Really surprised that it could have failed.
73; Steve, N3SB
|
Re: sBitx process no longer starts
A great summary by Steve, so is U7 suspect ? Are you getting voltage in or out of it ?
|
Re: sBitx process no longer starts
Isn¡¯t it so nice to have open source equipment? ? Makes it so much easier to diagnose.
I cracked this radio open for the first time today to show 4 middle school students, who were reasonably well impressed. ??
Guess what they elected to do the next time or a little ham club meets? ? They want to learn Morse code!
This puzzled me so we talked it over with an education major and she said that students of that age group love secrets. ?If I get them doing Morse code, I bet I can turn them into amateur radio operators eventually. ?They will be so pleased to be able to send secret messages!!
Gordon Gibby.?
toggle quoted message
Show quoted text
On Aug 18, 2022, at 18:16, Steve Beckman <ssteven3sb@...> wrote:
? Hi John;
The error message you're getting is coming from the i2cbb.c module (so great to have access to the sBitx source code!) That module is generating the error because it's finding the I2C serial data line is at a logic 0 / low voltage level when it should not be. Looking at the sBitx schematic, the Bit-Banged I2C bus communicates with the SI5351 synthesizer chip through pins 39 and 37 of the connector mating the digital daughterboard to the motherboard. Pin 39 is right on the end of the connector, so that's of note and worth a careful look. The SDA and SCL lines have to be pulled high with resistors R1 and R2, both 3.3 K Ohms, or else they can float low and cause this error.
So - possible problems: 1) Pin 39 from the digital board not mating properly with the motherboard - check that the digital board is fully inserted into the motherboard. 2) Regulator U7 on the main board not providing 3.3v to the SI5351 and the two pull-up resistors R1 and R2 3) R1 on the motherboard missing or damaged 4) SI5351 shorted / damaged
Hopefully it's just the mating of the digital daughterboard to the main motherboard - and you'll be back on the air shortly.
73; Steve, N3SB
On Thu, Aug 18, 2022 at 5:56 PM John Terrell, N6LN < N6LN@...> wrote: I also ran raspi-config to make sure i2c was enabled. No change. I get the same error.
|
John Terrell, N6LN
Willi, OE1WKL
