Is it fried? No TCXO

MMDVM_HS Hat hardware
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KN4IJP
Posts: 7
Joined: Mon Jul 01, 2019 2:02 pm

Is it fried? No TCXO

Post by KN4IJP » Sat Jul 06, 2019 8:53 pm

History- built my first hotspot on 7/3 with pi Zero and eBay MMDVM board. Followed directions by Toshen to a T and only enabled DStar. Setup home WIFI and iPhone hotspot.

Everything worked perfectly! Made several contacts from home WIFI on 7/3 and 7/4. Zero loss and 0% BER.

Then on 7/5 I took everything to work. Monitored DStar all day and made a couple contacts via iPhone hotspot. CPU temps were around 100-110 degrees.

After work I wanted to try mobile. Started Jeep, plugged iPhone into USB for power (that was connected to Car Play), turned on iPhone hotspot. Then I set Jumbospot in dash tray, activated OEM Jeep converter and plugged my Jumbospot into the 110v socket.

Jumbospot got really hot to the touch. Couldn’t connect with radio when keying up. Seemed like Jumbospot shutdown due to overheating. I realized that I had inadvertently set the Jumbospot on top of a large metal coin that was in the dash tray. My Jumbospot isn’t in a case yet. I wondered if I shorted something out?

When I got home I reconnect and noticed dashboard was showing everything in green except DStar on Modes Enabled. Also the CPU was up to about 150 degrees. I did a lot of forum and internet searching to diagnose it. The good news is I’ve learned a lot!

So...I completely reformatted the SD card, flashed Pi-Star again and setup everything from the beginning. DStar mode still red. CPU still hot. Started digging around in SSH (new to me). Ran update in SSH. Them tried to flash MMDVM firmware a couple times. Got a “failed to init device” error. It’s also mentioning something about Arduino.

Ran logs during reboot and get the failed to (something...) after six tries message.

What else can I try? What did I do wrong? Time for a new board?

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KE7FNS
Posts: 143
Joined: Wed Apr 17, 2019 11:11 pm

Re: Is it fried? No TCXO

Post by KE7FNS » Sat Jul 06, 2019 9:23 pm

KN4IJP wrote:
Sat Jul 06, 2019 8:53 pm
I realized that I had inadvertently set the Jumbospot on top of a large metal coin that was in the dash tray. My Jumbospot isn’t in a case yet. I wondered if I shorted something out?
That probably is what happened, you shorted something out on the Pi (since I assume it was the thing touching the metal coin), and could of borked the modem too if you shorted some pins on the GPIO.
KN4IJP wrote:
Sat Jul 06, 2019 8:53 pm
What else can I try? What did I do wrong? Time for a new board?
Well, I'd take the modem off the RPi and flash an OS on the RPi and test it to see if all the pieces and parts work. Like if it no longer gets hot when running the standard raspbian lite or just pi-star itself, its probably undamaged, then again you could of taken out some component like the serial port.

Then, I'd put the modem on another known working RPi and test it.

Sometimes those modems have a pad or pins you need to short (or button to hold down) in order to get the STM32 into the correct mode to accept the flash.

KN4IJP
Posts: 7
Joined: Mon Jul 01, 2019 2:02 pm

Re: Is it fried? No TCXO

Post by KN4IJP » Sat Jul 06, 2019 11:03 pm

Thanks for the feedback! I appreciate your help.

So I pressed the reset button on the MMDVM. After it reset I tried to flash the firmware again. No changes.

I removed the MMDVM board and restarted the Pi. Seemed hotter without the MMDVM.

Turned off power to Pi via Pi-Star. Waited 10-15 minutes. Pi was still pretty hot just being plugged into electricity even though it wasn’t powered on.

Restarted just the Pi without MMDVM. By the time it connected to WIFI show I could check Admin it showed 142 degrees.

Looks like the Pi was damaged? I’m wondering if the MMDVM was damaged as well? I don’t have another Pi or MMDVM board for additional testing. Going on an RV road trip in 2 weeks and wanted to use the hotspot. I hate to buy everything again if the MMDVM board is ok. Any way to test it through commands or logs?


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KE7FNS
Posts: 143
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Re: Is it fried? No TCXO

Post by KE7FNS » Sun Jul 07, 2019 7:50 am

KN4IJP wrote:
Sat Jul 06, 2019 11:03 pm
So I pressed the reset button on the MMDVM. After it reset I tried to flash the firmware again. No changes.
Nah, its not a reset button, it should be labeled "BOOT" or "Bootstrap" if the board designer bothered to put it on the silkscreen. You haven't mentioned which mmdvm board you have so I dunno what exactly to point you too. But when you find what I'm talking about, you need to short boot to whatever pin/pad it says in the instructions (normally found on a github page for the board design ), and then type the command at the prompt and hit enter to begin the flashing, then once it gets past that init phase, you can CAREFULLY remove the short or just wait until its finished and then remove it. If you leave BOOT shorted, the MMDVM STM32 won't boot and start running its program it'll just sit in bootstrap mode waiting for a connection.
KN4IJP wrote:
Sat Jul 06, 2019 11:03 pm
I removed the MMDVM board and restarted the Pi. Seemed hotter without the MMDVM.

Turned off power to Pi via Pi-Star. Waited 10-15 minutes. Pi was still pretty hot just being plugged into electricity even though it wasn’t powered on.

Restarted just the Pi without MMDVM. By the time it connected to WIFI show I could check Admin it showed 142 degrees.

Looks like the Pi was damaged? I’m wondering if the MMDVM was damaged as well? I don’t have another Pi or MMDVM board for additional testing. Going on an RV road trip in 2 weeks and wanted to use the hotspot. I hate to buy everything again if the MMDVM board is ok. Any way to test it through commands or logs?
While that does seem relatively hot to you and me, it really isn't anything to worry about when it comes to RPi cpu temps though, They are supposed to go into an automatic self throttling mode when they hit 80C, or 176F, so you shouldn't really be encountering any throttling yet and are still in a normal temp zone, so I'm not all that concerned. Normally when you pop electronics, they just quit altogether, so the fact that it seems to still be working and doing what its supposed to do is encouraging. I'm worried about the serial port, as you could of accidently put 5v to one of the TX/RX lines and nuked a controller, or the STM32 on the MMDVM board. Serial lines are 3v systems and don't really play well when you insert stray voltage on them.

The only way I can really think of testing it without a bunch of equipment you probably don't have is by doing what you are doing, and seeing if you can get the MMDVM to take a flash and communicate correctly with the RPi.

When you first power the MMDVM on do you see any LEDS light up or flashing? It should go through some sort of sequence, and no lights at all would indicate a serious issue. If the RPi boots to pistar and the MMDVM lights up, and you still can't get things to work, we need to start poking around in the logs.

Code: Select all

cat /var/log/pi-star/MMDVM-2019-07-07.log
the date is year-month-day, and every day theres a different log, they are also deleted when the RPi is rebooted/powered off.

Look for "Opening the MMDVM"
and it'll either say something good like "MMDVM protocol version: 1", or "failure to communicate with the modem after 6 tries". So yeah, the bad message would indicate either a problem with the serial port on the RPi or an unhappy MMDVM.

KN4IJP
Posts: 7
Joined: Mon Jul 01, 2019 2:02 pm

Re: Is it fried? No TCXO

Post by KN4IJP » Sun Jul 07, 2019 9:08 pm

Thanks for the tips. It looks like the Pi serial port may be bad.

All the lights on the MMDVM flash as normal on startup. Then the green light stays solid while the red service light blinks. Seems like that’s how it was before it broke.

A search for the MMDVM log shows “unable to read firmware version after six attempts” before and after a firmware flash holding down the button on the boot board. Also still getting the failed to init message after firmware flash.

Tried to test the serial port with minicom using sudo minicom -D /dev/ttyS0. Also tried sudo minicom -D /dev/tty8. Both with pins 8 and 10 connected. It shows Welcome to minicom message for both ports but doesn’t display any typing after that.

I think I’ll order a new Pi and maybe a new MMDVM.


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KE7FNS
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Re: Is it fried? No TCXO

Post by KE7FNS » Mon Jul 08, 2019 8:57 pm

KN4IJP wrote:
Sun Jul 07, 2019 9:08 pm
A search for the MMDVM log shows “unable to read firmware version after six attempts” before and after a firmware flash holding down the button on the boot board. Also still getting the failed to init message after firmware flash.
Well, if it isn't getting past the init phase, the modem isn't being flashed at all. When you see it sending data and counting up, then it's being flashed. Like I said, the modem needs to be powered up in a special mode for it to begin to accept a flash, not just reset. If theres both a button for reset and boot, then hold the boot button down and tap the reset, and then enter the flashing command at the prompt. You still haven't said which board you are using, so its difficult to provide the correct instructions.
KN4IJP wrote:
Sun Jul 07, 2019 9:08 pm
Tried to test the serial port with minicom using sudo minicom -D /dev/ttyS0. Also tried sudo minicom -D /dev/tty8. Both with pins 8 and 10 connected. It shows Welcome to minicom message for both ports but doesn’t display any typing after that.
Those are not the correct serial port names. It should be /dev/serial0 or /dev/ttyAMA0, /dev/ttyS0 is reconfigured to serial port 1 on pistar which is swapped when compared to normal raspbian, and I dunno where you got tty8 from.
KN4IJP wrote:
Sun Jul 07, 2019 9:08 pm
I think I’ll order a new Pi and maybe a new MMDVM.
Don't forget a case too.

KN4IJP
Posts: 7
Joined: Mon Jul 01, 2019 2:02 pm

Re: Is it fried? No TCXO

Post by KN4IJP » Mon Jul 08, 2019 9:20 pm

KE7FNS wrote: Don't forget a case too.
Haha; that’s awesome! The case just came today. Ordered it right before I fried the hotspot.

I’ll give these next steps a try tonight. The board is a generic Chinese board off eBay. The button on the board is a reset. I haven’t been able to find the directions to put it in flash mode yet.

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KE7FNS
Posts: 143
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Re: Is it fried? No TCXO

Post by KE7FNS » Thu Jul 11, 2019 2:18 am

KN4IJP wrote:
Mon Jul 08, 2019 9:20 pm
I’ll give these next steps a try tonight. The board is a generic Chinese board off eBay. The button on the board is a reset. I haven’t been able to find the directions to put it in flash mode yet.
Well, I guess I need to adjust what I said earlier.

Since I don't see any boot pads/pins to short out on the PCB, it goes into flashing mode by the serial lines being toggled in a specific sequence. Older boards still need the pads shorted, I assumed you had one of those picky boards. So, since either the serial port on the RPi or the STM32 is bad, that explains why that isn't working anymore. Odds are that if you were able to get it into boot mode, that it wouldn't accept the flash correctly anyways, since the port is dead.

There is another way to reprogram the STM32 (with some more hardware), but if the port is bad on the chip theres no point in that.

KN4IJP
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Joined: Mon Jul 01, 2019 2:02 pm

Re: Is it fried? No TCXO

Post by KN4IJP » Fri Jul 12, 2019 7:47 pm

I got it working. Looks like it was the serial port of the raspberry pi. Bought a new Pi.

In the case! Thanks for all your help!

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KE7FNS
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Re: Is it fried? No TCXO

Post by KE7FNS » Sat Jul 13, 2019 7:35 pm

KN4IJP wrote:
Fri Jul 12, 2019 7:47 pm
I got it working. Looks like it was the serial port of the raspberry pi. Bought a new Pi.
Congrats, looks nice and protected.

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