Just preordered Pyra and Pandora questions

[triblelife]

Hello, everyone. i am a new here in this large and talent community. i saw some forums before and some talent people discuss hardware and software things. i really enjoy this community.
for me, i am a software guy, but curious and want to learn hardware things. i really love open source things. i start with Raspberry pi and Arduino, then i found there is a linux handheld called pocketchip from Next Thing Co. after some playing and then i found there is a more powerful one called Openpandora.
fortunately, i found one from Ebay, i have bought it an start to play with the linux little while. then i opened the case to discovery the hardware and want fix the problem with USB host, (because the pandora was sold as broken for USB). i found that the USB was loose. so i replaced a new one by myself.

After all, it was great and has been fixed for the USB. but after playing a little bit, it was stuck and i cannot open some application like User Manager and Switch UI. after attempting to open the application few times, my baby pandora died with some vertical lines followed by black screen and non LCD works. Then, try to restart it with replacing battery and followed by black screen and no LCD. sometimes it start to boot but followed by some vertical lines and turned to black with screen back light and only right green LCD. but most of the time it was no reaction at all, no backlight, no LCD. but the USB seems works for electric output. i want it back to me. i gonna figure it out, maybe there is some software problem.

after all, i decide to preorder a new generation, Pyra. i will follow this talent community and try to learn more stuffs.

 

[comradekingu]

Welcome
Sounds like your LCD-cable is broken. You can get replacement ones from Dragonbox.de

 

[triblelife]

Welcome
Sounds like your LCD-cable is broken. You can get replacement ones from Dragonbox.de

Thank you so much for fast reply.
I agree with you that the LCD cable has to be replaced. But I have a little question that does the pandora run without LCD ? Cause I tried to boot it up without the LCD cable and screen. It does not react as the one with the LCD cable and screen.
Again thank you so much for reply.

 

[Linux-SWAT]

Yes, you can run without a screen.

 

[triblelife]

Yes, you can run without a screen.

So, I tried to turn it up without LCD cable. It still does not react or turn on any light.
Than you so much for replying.

 

[TrashyMG]

So, I tried to turn it up without LCD cable. It still does not react or turn on any light.
Than you so much for replying.

Any light? are you getting any LED boot lights and such? are you getting a power indicator light?

 

[triblelife]

Any light? are you getting any LED boot lights and such? are you getting a power indicator light?

No light at all. No boot light no sd card light no power indicator light. But there is electronic output from the USB host.
Thank you.

 

[TrashyMG]

No light at all. No boot light no sd card light no power indicator light. But there is electronic output from the USB host.
Thank you.

Is that when it's on the charger or on the battery only? If it's on the charger there may be power to the USB host at that point.

If your battery is drained too much, it will trickle charge until the battery has enough power to fully boot up. If it's on the charger for more than 30 minutes and it's still not booting up, check the battery connectivity. First batch units had a tendency of shifting a bit.

 

[triblelife]

Is that when it's on the charger or on the battery only? If it's on the charger there may be power to the USB host at that point.

If your battery is drained too much, it will trickle charge until the battery has enough power to fully boot up. If it's on the charger for more than 30 minutes and it's still not booting up, check the battery connectivity. First batch units had a tendency of shifting a bit.

Thank you for fast reply.
It is on the battery and charger that both have the output from USB host.
It is rebirth edition. The battery connection is ok, as I checked. And I charged it for a whole night. But still no reaction. Sometimes, maybe three times. It booted up, but followed by vertical lines and then turn to black screen with screen back light and left green light. After long time, it stuck with that situation. After I pulled out the battery and pulled it back. It becomes no actions at all.
Again thank you!

 

[TrashyMG]

hmm, that's a tough one.

If you took the battery out and put it back in when it's running on the charger it may have done damage to the charging circuit. You could try taking out the battery completely and running it on the charger only, see if it lights up. Just remember don't put the battery in when powered by the charger. Most Pandoras can run on the AC charger without the battery, this won't work on USB charging.

This could at least eliminate the battery from the equation.

 

[triblelife]

hmm, that's a tough one.

If you took the battery out and put it back in when it's running on the charger it may have done damage to the charging circuit. You could try taking out the battery completely and running it on the charger only, see if it lights up. Just remember don't put the battery in when powered by the charger. Most Pandoras can run on the AC charger without the battery, this won't work on USB charging.

Yeah, I kind of discovery the old posts for that kind of problem. I tried what you mentioned. It does not works though. Oh, I remember that one time I pull the battery in when the charger is on.
Thank you !

 

[levi]

Hmm, I've heard that if you do plug a battery into a unit that's wired in to +5V, there's a good chance the power circuitry will get confused enough to try itself. The only way I know to test that is to yank the motherboard out and power it up using a bench supply and croc clips to the + and - copper nodes on the sides of the board. Power that way should bypass the power circuit as far as I know, and if you get lights that way, then it's probably the power/charge circuitry that's at fault.

 

[triblelife]

Hmm, I've heard that if you do plug a battery into a unit that's wired in to +5V, there's a good chance the power circuitry will get confused enough to try itself. The only way I know to test that is to yank the motherboard out and power it up using a bench supply and croc clips to the + and - copper nodes on the sides of the board. Power that way should bypass the power circuit as far as I know, and if you get lights that way, then it's probably the power/charge circuitry that's at fault.

Thank You so much to reply. i will give it a try right now to see is it that problem.
again, thank you for fast reply.
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Hmm, I've heard that if you do plug a battery into a unit that's wired in to +5V, there's a good chance the power circuitry will get confused enough to try itself. The only way I know to test that is to yank the motherboard out and power it up using a bench supply and croc clips to the + and - copper nodes on the sides of the board. Power that way should bypass the power circuit as far as I know, and if you get lights that way, then it's probably the power/charge circuitry that's at fault.

Unfortunately, it does not response that way either.

 

[Splintercat]

You probably have a short.
I'd disconnect the LCD cable to make sure that's not the culprit.
Past that, start really looking around the new USB port you put in. You might have created a solder bridge, or if you used too much heat, may have warped some of the nearby lines.

My original Pandora has a broken USB that I've tried to fix once or twice.

 

[triblelife]

You probably have a short.
I'd disconnect the LCD cable to make sure that's not the culprit.
Past that, start really looking around the new USB port you put in. You might have created a solder bridge, or if you used too much heat, may have warped some of the nearby lines.

My original Pandora has a broken USB that I've tried to fix once or twice.

yeah, i already disconnected my LCD with Board itself and tried some cables and chargers. it seems does not response either. As you said, probably i burned something on my board when i try to solder the USB port.

Thank you !

 

[WizardStan]

there's a good chance the power circuitry will get confused enough to try itself

I wouldn't say it's a good chance, but there is a chance. It's certainly not recommended but it wouldn't be my first assumption of a problem.
I would recommend plugging it in to charge and leaving it for an hour, see if it eventually starts up, and if it doesn't start up does it at least get warm. The battery will get warm if it is charging properly; if it stays cold then there is a problem with the power circuit. There's not much that can be fixed in that case.

 

[triblelife]

I wouldn't say it's a good chance, but there is a chance. It's certainly not recommended but it wouldn't be my first assumption of a problem.
I would recommend plugging it in to charge and leaving it for an hour, see if it eventually starts up, and if it doesn't start up does it at least get warm. The battery will get warm if it is charging properly; if it stays cold then there is a problem with the power circuit. There's not much that can be fixed in that case.

The green light is up after this trying. But it is same as before. There is no response to SD card insert. Only green light. Maybe, after I unplug this time, it will never boots up again like this. It is totally random.

 

[levi]

I considered it being a short, as I've caused that to my own unit due to hamfisted attempts to get that damn LCD cable inserted in the past. But if it does come up three times out of a few dozen then it's not a 'good' short that starves the CPU of enough V+ to go. There might be a slow short complicating things and draining the battery, but I suspect there's more to it than that.

FWIW I fixed my own short by having it hooked up to my bench supply then upping the maximum amperage until finally the errant pins in the LCD connector released their magic fire at around 3.5A. I then pulled off the LCD connector, and my system became able to boot normally ever since, albeit leaving the case lid and LCD just ballast in the case. Because I only had a shitty flux pen that had long dried up I did end up almost literally ripping the part off by force, lifting some traces, but if you have better kit than me you might be able to replace parts instead. If you have a slow short, it might come to life before the short burns itself out though, and then you'd be best seeing what got hot perhaps.

 

[triblelife]

I considered it being a short, as I've caused that to my own unit due to hamfisted attempts to get that damn LCD cable inserted in the past. But if it does come up three times out of a few dozen then it's not a 'good' short that starves the CPU of enough V+ to go. There might be a slow short complicating things and draining the battery, but I suspect there's more to it than that.

FWIW I fixed my own short by having it hooked up to my bench supply then upping the maximum amperage until finally the errant pins in the LCD connector released their magic fire at around 3.5A. I then pulled off the LCD connector, and my system became able to boot normally ever since, albeit leaving the case lid and LCD just ballast in the case. Because I only had a shitty flux pen that had long dried up I did end up almost literally ripping the part off by force, lifting some traces, but if you have better kit than me you might be able to replace parts instead. If you have a slow short, it might come to life before the short burns itself out though, and then you'd be best seeing what got hot perhaps.

As so far, I disconnect the LCD cable and there is nothing hot on the board yet. I did tried using bench supply. It was same as usual.
This is the status right now. The green light up and it sticker there no lother light when I insert SD card. No red light for powering. And I also took the picture of the USB port I sordered on. And I checked if it is hot on USB. But not, the USB is not hot either. Thank you.
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Also, I want to mention that when I take out the old USB host. There is copper circle comes from the main board also. Is that the short circuit problem? If it is I would pull out the new one. Thank you !

 

[levi]

No idea about the copper circle. Never had my USB-A socket off, so I've never seen it, but I guess that if it's connected to anything it's connected to GND.

I suppose I should clarify that when I was talking about shorts getting hot, that only applies to a short between something close to V+ and something close to GND. If some TTL lines get shorted together, it'll just do weird stuff, and not normally get significantly hotter anywhere, but it also won't drain the battery especially quickly, and the system will generally still have power.

I said I didn't think you had a hot short, but it's possible you have a data short. Although if with LCD connected you saw an image that changed periodically makes me think it's actually booting fine.

Does the green power LED always power up when you power it via those pads? The red charging LED does not normally light when powering that way, I think. But in my experience, the appropriate SD light should at least flicker when you insert a card, as the automounter does its stuff. I think that gets set up pre-login, so as long as you give the system time to boot, the SD lights should flicker briefly when you put a card in.