[PROBLEMO] Er9x Will not boot / past splash ! wtf

[jhsa]

What is the reading? 0 ohms? 200 ohms? open circuit?

João

[Charlie86]

have to get back to you on that bear with me!

[Charlie86]

Ok so instead of reading the Voltage or Mv I switched to Ohm mode and get a reading of 198 . .

http://i.imgur.com/ay9BipV.jpg

[MikeB]

Right, between the switch and the SCK pad is a 200 ohm resistor. Where have you measured the 198 ohms? switch or SCK pad. Which one determines where to look for a short.

I know it's taking time, but stick with it. We should be able to fix it.

Mike.

[Charlie86]

Ok thanks for the help I really appreciate it, either way I measure it gives me the same 198.+- reading

[Charlie86]

http://i.imgur.com/k7YzBZd.jpg

[MikeB]

Sounds odd, so I have to ask. Are you measuring between GROUND and the SCK pad and between GROUND and the switch? (Not between the switch and the SCK pad).

On the picture I posted some post back, the switch has 4 legs. The top 2 are GROUND, the lower 2 (connected by a track) are the switch. Using one of the two GROUND pads of the switch, measure the resistance to the the other side of the switch, then again from one of those two GROUND pads, measure the resistance to the SCK pad.

Apologies if this is what you have done, but if it is, and they both read 198 ohms, I'll need to think very carefully what may be wrong as such a result is very unexpected.

The picture you have posted while I'm typing shows you measuring between the switch and the SCK pad as far as I can see.

Mike.

[Charlie86]

Ok before I was using the Volts meter so I wasnt getting any reading unless The TX was ON so now using the Ohms mode - between GROUND and SCK I get about 3.62 and between the top and bottom legs of the switch I get about 3.8 Ohms

[jhsa]

You must measure the ohms with the radio powered OFF. Better yet, remove the battery.

Sent from my GT-I9195 using Tapatalk

[Charlie86]

That is what I did are those readings completely unexpected ?

[MikeB]

Hmmm, still a surprise since you measured 198 ohms between SCK and the switch.
Can I ask you to measure again please? I would expect one measurement to be low, like the 3.8 ohms, but the other to be around 200 ohms.

I've had a close look at you board from the last picture you posted.
Two things:
1. Where the blue wire is soldered to a PAD, just to the left of the processor, it looks like the solder might catch a via hole.
2. The track from the MENU switch goes under the connector you added:

Check nothing on that track is connecting to any of the pins of the connector.

Mike.

[Charlie86]

Yes the measurement between ground and SCK is around 3.6 and from SCK to switch its 199

[Charlie86]

http://i.imgur.com/WpF3hpb.jpg

[MikeB]

From the information so far, it seems the problem may be on the SCK pin.
My next suggestion is to unsolder the wire to the SCK pad and measure the resistance from the PAD to GROUND again.
With the wire removed, a close up picture of that area may also be useful.

Also, just to the left of the menu button pads, the signal track looks to have a solder 'flash' on it. I don't think it is shorting to anything, but it is worth removing. After soldering, you end up with flux residue on the board. It is a good idea to remove this. I use a "cotton bud" soaked in a little cellulose thinners (might be called a Q-tip). Nail varnish remover can also work.

Mike.

[Charlie86]

Unsolder wire done
Remove residue done

Here is the close-up

http://i.imgur.com/A0W11IW.jpg

Nonetheless I get the same readings :-/

[MikeB]

If you have a reading of 3.6 ohms from the SCK pad to GROUND, about the only conclusion, looking at the board, is there is a problem inside the processor.

Odd again, since earlier you said you could still read/write the EEPROM, which needs the SCK pin to work.

Do you have any resistors lying about? Something from 1K0 to 2K2.

If so, you could try wiring a resistor from the switch signal to +5V, power the board up, then measure the VOLTAGE at the switch signal and at the SCK pad.

Mike.

[jhsa]

Mike, do you think that the processor pin might be grounded?

Sent from my GT-I9195 using Tapatalk

[Kilrah]

No as if it was programming wouldn't work.

Could be the GPIO circuitry inside the processor that is dead, while the programming circuitry connected to the same pin is still OK.

[Charlie86]

I have resistors in that range so I will give it a go later but just for info the TX was working flawlessly until I recharged the battery, would this have anything to do with these issues ( say if I used the wrong type of charge setting ) ?

On the other hand I have another 9x where I connected the battery reverse polarity ( magic smoke) is there any way I could salvage this other 9x ?

[Charlie86]

Or maybe transplant the processor ( Im guessing not )

[ShowMaster]

Where does he live? Tap a talk doesn't display it.


Sent from my iPod touch using Tapatalk, small keys and a big finger.

[jhsa]

No as if it was programming wouldn't work.

Could be the GPIO circuitry inside the processor that is dead, while the programming circuitry connected to the same pin is still OK.

That's what I meant..

Sent from my GT-I9195 using Tapatalk

[Charlie86]

At the moment I live in switzerland but I am often in north western Germany near Holland to visit it relatives ..

[jhsa]

I live in North western Germany (NRW). Not very far from Münster.. Send me a private message if you will be in the area

[Charlie86]

Thanks jhsa

For now I will be just buying a new TX for €90 but maybe my cousine could bring the broken one to you because she also lives in that area ..

Could you please send your address via PM / PN

so I can see how far away it is

Thanks again for all this help!

[Charlie86]

Hey jhsa how's it going

[jhsa]

Hey.. Great. I take it you too..

João