assembly caused issues

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sp5
 

Posts: 6
Joined: 03 Jan 2022, 20:20

assembly caused issues

Post by sp5 »

Hi,
I've assembled both boards, but probably with errors. Let me describe my problem:
1. Manually soldered SMD components on the mainboard seem to be properly connected, but it is very hard to fully assess if there is no bridges. I asses quality of my SMD connection as very low, it took some time to solder it. I was trying not to fry the elements, but who knows...

2. After connecting both boards together I have managed to upload the bootloader and the serial number was displayed.
3. I was unable to upload firmware as the device was not recognized as the USB device (at all- no sign of connection on the computer side).
4. After separation of RF board, I recognized that the device is connected and recognized by the computer, and the firmware was successfully uploaded.
5. Unfortunately, after connection of the RF board, it stopped responding again - no sign of life, "brick mode". Separation of RF boards allows for operation of the menu.

I have checked for short circuits between vcc and gnd and between gnd and other pins - no sign of a very low resistance.
Do you have any clue what I may screwed up and tips what and how to check?

Thanks and best regards!
mm0gyx
 

Posts: 83
Joined: 30 Dec 2021, 20:22

Re: assembly caused issues

Post by mm0gyx »

sp5 wrote: 01 Apr 2022, 07:42 Hi,
I've assembled both boards, but probably with errors. Let me describe my problem:
1. Manually soldered SMD components on the mainboard seem to be properly connected, but it is very hard to fully assess if there is no bridges. I asses quality of my SMD connection as very low, it took some time to solder it. I was trying not to fry the elements, but who knows...

2. After connecting both boards together I have managed to upload the bootloader and the serial number was displayed.
3. I was unable to upload firmware as the device was not recognized as the USB device (at all- no sign of connection on the computer side).
4. After separation of RF board, I recognized that the device is connected and recognized by the computer, and the firmware was successfully uploaded.
5. Unfortunately, after connection of the RF board, it stopped responding again - no sign of life, "brick mode". Separation of RF boards allows for operation of the menu.

I have checked for short circuits between vcc and gnd and between gnd and other pins - no sign of a very low resistance.
Do you have any clue what I may screwed up and tips what and how to check?

Thanks and best regards!
Does it not turn on at all when you power up with boards connected together?

I’m guessing here but maybe there’s a fault with the soldering to RF board U1 or U7, if you fitted them. I know someone who fitted U7 the wrong way around. Perhaps you could look there.

Ian MM0GYX
sp5
 

Posts: 6
Joined: 03 Jan 2022, 20:20

Re: assembly caused issues

Post by sp5 »

Thanks for the answer, the RFs U1 and U7 are correctly placed (those were assembled at JLPCB).
While both boards are connected it does not turn on. Separate mainboard yes. Any ideas are welcome.

p.s. I can add that while both boards are connected and USB power is on, a ~2-3Hz silent sound is observed coming from the assembly (but speker is not soldered yet!)
AC9YY
 

Posts: 133
Joined: 21 Mar 2022, 00:04
Location: Illinois, USA

Re: assembly caused issues

Post by AC9YY »

sp5 wrote: 01 Apr 2022, 12:58 Thanks for the answer, the RFs U1 and U7 are correctly placed (those were assembled at JLPCB).
While both boards are connected it does not turn on. Separate mainboard yes. Any ideas are welcome.

p.s. I can add that while both boards are connected and USB power is on, a ~2-3Hz silent sound is observed coming from the assembly (but speker is not soldered yet!)
Make sure you have one side of the case on where the 6 pin connector is to prevent shorts.
sp5
 

Posts: 6
Joined: 03 Jan 2022, 20:20

Re: assembly caused issues

Post by sp5 »

The ISP is separated, so it was not the case. New observations so far:
1. With two boards connected the VCC pin showed 0V to GND instead of 5V. PA transistors were warm after a few seconds of "dead" opeartion
2. I removed all Q1-Q3 PA transistors and the sandwich has begun to work (at least in the field of display and basic ATMega region).
I am trying now to find possible shorts or other mistakes in the RF circuits. If you have ideas what to check next, I will appreciate. :D
AC9YY
 

Posts: 133
Joined: 21 Mar 2022, 00:04
Location: Illinois, USA

Re: assembly caused issues

Post by AC9YY »

sp5 wrote: 01 Apr 2022, 15:02 The ISP is separated, so it was not the case. New observations so far:
1. With two boards connected the VCC pin showed 0V to GND instead of 5V. PA transistors were warm after a few seconds of "dead" opeartion
2. I removed all Q1-Q3 PA transistors and the sandwich has begun to work (at least in the field of display and basic ATMega region).
I am trying now to find possible shorts or other mistakes in the RF circuits. If you have ideas what to check next, I will appreciate. :D
Based on what you are saying I would check the signal going to the gates of the FETs. If it is a constant high signal it would turn them on all the time causing the issue you are seeing. Likely cause is a solder short or open pin somewhere.
dl1bax
 

Posts: 8
Joined: 02 Jan 2022, 08:01

Re: assembly caused issues

Post by dl1bax »

Hello everyone.

Exactly the same problem as mine. Main board without RF, everything works, firmware was loaded, menu complete.

As soon as the RF board is plugged in, the current increases to 250 mA and no longer functions. I have checked several times for short circuits and incorrect assembly.

Don't know.

Ralph, DL1BAX
mm0gyx
 

Posts: 83
Joined: 30 Dec 2021, 20:22

Re: assembly caused issues

Post by mm0gyx »

dl1bax wrote: 02 Apr 2022, 22:37 Hello everyone.

Exactly the same problem as mine. Main board without RF, everything works, firmware was loaded, menu complete.

As soon as the RF board is plugged in, the current increases to 250 mA and no longer functions. I have checked several times for short circuits and incorrect assembly.

Don't know.

Ralph, DL1BAX
I think in both cases you guys have static damaged bs170 which are conducting even on rx. I’ve seen this fault before. It is my belief that static builds up on the drive pin of header (due to handling without taking esd precautions) and that is connected to gates. I know more than one person who applied power to see smoke, on rx!

If you have not removed the 170 yet, with rf board removed check resistance from drain to gate, I had one to fix where there was a dead short, this was a failed 170 of course. Resistance should be high, if it is very low, 170 is dead, and all 3 should be replaced.

Ian MM0GYX
DF6MZ
 

Posts: 11
Joined: 04 Jan 2022, 09:27

Re: assembly caused issues

Post by DF6MZ »

I do have the same problem with my kit. I measured the resistance and it is high on all three 170.

Martin, DF6MZ
mm0gyx
 

Posts: 83
Joined: 30 Dec 2021, 20:22

Re: assembly caused issues

Post by mm0gyx »

DF6MZ wrote: 03 Apr 2022, 08:47 I do have the same problem with my kit. I measured the resistance and it is high on all three 170.

Martin, DF6MZ
Well, based on the op’s experience, he removed the 170s and the rig turned on. In that case I guess removing the 170s is a bit of a chore just to test. Maybe if you remove L15, to take the supply from the drains then try it, if there’s a snag in the Pa it should turn on, right?

Obviously it’s not a good idea to turn the rig on in fault condition, removing L15 removes the supply from drain, and will hopefully allow you to turn the rig on and test the rx, and diagnose the power fault.

Also, like AC9YY suggested already, check there is no voltage on the gates in rx. Although, to do that you’d need to attach both boards and power it. Probably best to avoid powering until you remove drain voltage. Or, check it at the drive pin of the mainboard, powered and separated.
DF6MZ
 

Posts: 11
Joined: 04 Jan 2022, 09:27

Re: assembly caused issues

Post by DF6MZ »

Thank you very much for your help, I really appreciate it! I removed L15 and it turned on with the RF board attached, but for just a second. Then the display went upside down and then showed just gibberish. The mainboard alone seems to still work fine. Without the RF board connected, the voltage on the drive pin is 0.
mm0gyx
 

Posts: 83
Joined: 30 Dec 2021, 20:22

Re: assembly caused issues

Post by mm0gyx »

DF6MZ wrote: 03 Apr 2022, 09:34 Thank you very much for your help, I really appreciate it! I removed L15 and it turned on with the RF board attached, but for just a second. Then the display went upside down and then showed just gibberish. The mainboard alone seems to still work fine. Without the RF board connected, the voltage on the drive pin is 0.
That oled behaviour could be a separate fault, try powering just mainboard on its own to view oled performance.
DF6MZ
 

Posts: 11
Joined: 04 Jan 2022, 09:27

Re: assembly caused issues

Post by DF6MZ »

With the mainboard alone, the OLED works just fine.
dl9tx
 

Posts: 10
Joined: 04 Jan 2022, 10:18

Re: assembly caused issues

Post by dl9tx »

Hello, I had the same problem today with my RF board. I've found the problem, see the link

viewtopic.php?p=2237#p2237
DF6MZ
 

Posts: 11
Joined: 04 Jan 2022, 09:27

Re: assembly caused issues

Post by DF6MZ »

Thanks a lot! I took off the transistors and now it works. Also, the display works just fine. I will put in some new transistors the right way round.
sp5
 

Posts: 6
Joined: 03 Jan 2022, 20:20

Re: assembly caused issues

Post by sp5 »

Hi again,
after some time I managed to find a bridge on one of the boards and found that I have a different BS170 pinout case. Both seems to be solved now (with a new transitors), thanks for your tips.

Unfortunately I am still figthing with the rig. Now the device is turning on, but I can't receive anything (just some high frequency noise is heard coming from the speaker but changing with frequency setting). I have found that there is a zero resistance between antenna output and GND on the separate RF board - Is this correct? What else I may check? I can't hear any difference in TX despite the device is connecte to the antenna (longwire) or not.

Best regards,
Marian SP5MHO
AC9YY
 

Posts: 133
Joined: 21 Mar 2022, 00:04
Location: Illinois, USA

Re: assembly caused issues

Post by AC9YY »

sp5 wrote: 11 Apr 2022, 19:03 Hi again,
after some time I managed to find a bridge on one of the boards and found that I have a different BS170 pinout case. Both seems to be solved now (with a new transitors), thanks for your tips.

Unfortunately I am still figthing with the rig. Now the device is turning on, but I can't receive anything (just some high frequency noise is heard coming from the speaker but changing with frequency setting). I have found that there is a zero resistance between antenna output and GND on the separate RF board - Is this correct? What else I may check? I can't hear any difference in TX despite the device is connecte to the antenna (longwire) or not.

Best regards,
Marian SP5MHO
Resistance from antenna output to ground should be 0 ohms or very closed to it. Check T1 and T2 for bad solder connections.
AntonR
 

Posts: 20
Joined: 23 May 2022, 10:44

Re: assembly caused issues

Post by AntonR »

Hi, I have the same problem, BS170’s running hot and I don’t know if the resistance between drain and source should be 0 as is the antenna to ground…
DL2MAN
 

Posts: 706
Joined: 30 Dec 2021, 19:18
Contact:

Re: assembly caused issues

Post by DL2MAN »

AntonR wrote: 16 Jun 2022, 20:59 Hi, I have the same problem, BS170’s running hot and I don’t know if the resistance between drain and source should be 0 as is the antenna to ground…
In both cases: It´s most likely damaged BS170´s (or soldered in reversed).
In both cases: Remove them, check, if the rig behaves normal (exept for missing TX PWR of course) and if yes: Get a new set of BS170s

73 Manuel; DL2MAN
k.eckert
 

Posts: 1
Joined: 02 Jan 2022, 19:17

Re: assembly caused issues

Post by k.eckert »

Moje uSDX po sestaveni nešlo. Zkrat na 1 tranzistoru. Po výměně nových 3 ks které měly přehozeny pin 1-3 už trošku žije. Ale sem tam se seka , zrcadlové zobrazeni , restart OK

ADMIN EDIT: Please read the forum rules: Posting in English only !
Ohwenzelph
 

Posts: 207
Joined: 01 Jan 2022, 03:47

Re: assembly caused issues

Post by Ohwenzelph »

"My uSDX did not work after assembly. Short circuit on 1 transistor. After replacing the new 3 pieces that had tossed pins 1-3, they are a little alive. But here and there the cut, the mirror image, restart OK"
Per google translate
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