FS TH9x won't turn on

means197 · Post by **means197** » Sat Sep 20, 2014 11:46 pm

I have a FS TH9x that I got last christmas, since that time, I've added a back light from HK, soldered on a usbAsp connector, and flashed with er9x. I've been using it without any problems until three days ago. I had the transmitter on in my garage verifying that all of my channels were set up properly so I could go flying the next day. The transmitter was just sitting on my bench and occasionally I would wiggle a stick. At one point I looked back at it and noticed that the back light was on, but otherwise the screen was blank. I assumed the transmitter battery (1500mAh 9.9V LiFe) was running low so the tx turned off. So I pulled the battery pack, and charged it, threw all of my gear in the car to fly the next day. But sadly my tx wouldn't turn on, so there was no flying. Does anyone have any suggestions of what to check??? When I turn it on, the back light comes on fine, but otherwise I can't tell that the tx is doing anything, and my receiver doesn't respond to the tx so I assume its not just the display not showing up.
here is what I've done thus far.
I re-flashed the firmware without any problems.
I re-wrote a clean eprom file.
I opened it up, and verified that everything appears to be firmly connected.
I didn't see any obvious signs of a fired component.
So now I have a brick for a tx and some planes that need flying. Any help will be greatly appreciated.

Thanks
Jason Means

Post by **MikeB** » Sun Sep 21, 2014 8:08 am

If you can still flash it and read/write the EEPROM then it is not bricked.
The most likely is no power getting to the processor.
1. Check all connectors are fully plugged in to the main board.
2. Power on and measure the voltage at the two regulators, one should have 5 volts and the other 3.3 volts.

Mike.

means197 · Post by **means197** » Mon Sep 22, 2014 3:01 am

I'll give that a try when my daughter takes a nap. I'm new to electronics, so can you tell me what the regulators look like? Are they the orange caps

means197 · Post by **means197** » Mon Sep 22, 2014 3:52 am

I checked all of the voltages off the regulators. Attached is a picture I took with the readings. "X" denotes no reading. I was using the ground off the power switch. I assume the reading all look good. As you can see from the pic, nothing looks fried, and I cannot smell anything. I unplugged and then plugged back in everything, but I still can't get it to turn on. Any other thoughts on what to check.
Thanks for all your help/insight.

Jason

Post by **jhsa** » Mon Sep 22, 2014 6:20 am

Are you sure the radio doesn't control the servos?
I'm asking because we have seen similar problems and most of them was just the LCD that stopped working as far as I remember.. And if that is the case, it could be one of the resistors above the processor that went bad..

João

means197 · Post by **means197** » Tue Sep 23, 2014 1:27 am

Joao, you were correct. I just plugged it back in and it is sending a signal. So I guess it is one of the resisters. I bet I had a switch flipped when I tried it before so the radio never made it past the switch error screen. Do you know how to test/what to look for in the resisters? Is there an article I can reference.
Thank you for all your help

Post by **MikeB** » Tue Sep 23, 2014 10:36 am

The resistors are in two lines, just to the right of the regulators. They are 5K1 and 10K, probably marked 512 and 103. Look closely and make sure they all look soldered properly, and also follow the tracks from the 512 ones to the processor and make sure the processor pins look soldered down, then check the pins of the connector to the LCD look to be soldered as well.
To test the processor and LCD pins, a good way is to take a needle and gently try to move each pin sideways. It should be obvious if it moves. Some sort of magnification also helps you to see!

Mike.

Post by **jhsa** » Tue Sep 23, 2014 12:35 pm

Adding to what Mike already said check if the LCD is properly inserted in the connector and the 2 little tabs on both sides of the connector are closed. Also measure the resistors with a multimeter, with power off of course. Some should read about 5100 ohms (5.1k (kilo ohms) ) and the others around 10000 ohms (10K (kilo ohms) ).
Good luck.

Post by **ShowMaster** » Tue Sep 23, 2014 12:47 pm

Good troubleshooting everyone. I'm sure the switch setting was keeping the tx for outputting any ppm. Good find. Hopefully it's just the LCD connector mating as suggested now.

For a probe, I use the thin bamboo BBQ skewers. Inexpensive, sharp on one end, non conductive. For added versatility, I actually insert a needle in the flat end and connect a thin insulated wire to it. That way I have a softer insulated probe end, a sharp pin end, and a meter probe if needed that sticks when pushed into a solder connection. Non skip.
SM

means197 · Post by **means197** » Wed Sep 24, 2014 3:16 am

You guys are awesome. I truly appreciate all of the assistance. So here is the update. I checked all of the resisters and the processor to verify that all of the connections are solid. Now since I don't always make good decisions and I didn't see SM's post until now, I used a needle (luckily I didn't hit anything with residual power).
As to the questions about the LCD connector, I have re-seated it several time without any luck.
So my next step it to measure the resistors. Thank you to Jhsa for the specs. I will report back tomorrow with my findings. Hopefully I will find a bad one (or two) so we/you can call this "case closed".

Thanks again for all your help
Jason

Post by **ShowMaster** » Wed Sep 24, 2014 5:29 am

Not the best picture of my probe but it'll give you the idea. I use it a lot.

hmarkvitz · Post by **hmarkvitz** » Fri Jun 05, 2015 12:17 am

I am having the same problem as the original poster. Just wanted to know if there is any way you guys can help me with this. I made a video and uploaded it to Youtube explaining my problem. I bought a Flysky TH9X and upgraded the firmware to ER9X using a usbasp module I bought on ebay. I had to solder a 10 pin connector to the board to do this. I also upgraded the screen with a backlight from Hobbyking. At first, I was using the supplied battery adapter with 8 rechargeable AA batteries and everything worked fine. I then started using a LiFe 1500mah 9.9v orange battery I bought from Hobbyking. After some time, I started noticing my 9 channel receiver that came with the transmitter wasn't functioning correctly once in a while. I don't really know if it was the receiver because I would lose control of my NAZA-M equipped F450 and this is why I assumed it was the receiver. I went ahead and ordered a Frsky DJT module with telemetry and a D8R-XP receiver. When I tried to install this piece, I noticed it sticked out and found a forum that explained you had to trim a part of the TH9X so it completely fit in the transmitter. I did all this and when tried the transmitter, just get a blank screen. The module will turn on, and I have tried to usbasp module to reflash my transmitter. The result is the transmitter powers on correctly, can be flashed, but gets a EEprom error and formats it. I made a video so you would better understand. Any help would be deeply appreciated. As you can see, I am very new to the hobby and don't know much. I don't want to buy a new transmitter if this is fixable but am not an expert on electronics or radios.

This is the link to the video: https://www.youtube.com/watch?v=hu5otcCmHsc

Post by **ShowMaster** » Tue Jun 09, 2015 2:26 pm

Ok, some answers
Your not getting voltage to the 5v regulator on the main board or the regulator isn't working, broken or bad solder connection on the leads?
The USBasp is powering your cpu via your computer and that's why it works then. It's supplying the required 5 volts the main battery and regulator isn't. Your voltage reading on the screen is what the radio voltage circuit is seeing from your computer, probably a normal voltage for this Usbasp power since the display and CPU runs on it and you can flash the CPU.

You don't want to keep flashing the CPU FW as you can wear it out. The eeprom error is normal after a FW flash and the formatting is required every time the FW is flashed, this is a normal error that fixes itself the first time
After a successful flash.

My opinion is that some how doing all your mods, the battery voltage 9.9 for your life04 isn't getting to the 5 volt regulator, or the regulator isn't outputting 5v. A closeup picture of your board would help us eyeball your work and see what's going on with the 5v regulator circuit board area and solder connections. The 5v regulator is the one top left of center from memory.

This schematic should be close enough to use. There have been changes over the years but give it try.
http://www.rcgroups.com/forums/showatt. ... id=3857016

Post by **ShowMaster** » Tue Jun 09, 2015 2:32 pm

Here's the 5v regulator cut I'd check out as well as 5v on pin 52 VCC. Don't measure on the CPU pin with power in, you could slip! Find the circuit trace feeding it or the and cap near the regulator. A picture please.

The schematic I posted looks to have the regulator pins mislabeled. I'll look for a better one.

Post by **jhsa** » Tue Jun 09, 2015 2:55 pm

Here are the places where you can measure the voltages. Please check the picture. Measure between point A and G, and between B and G (ground). You can see the expected voltages marked in yellow.

João

EDIT: Be careful not to short anything with the probes..

Post by **ShowMaster** » Tue Jun 09, 2015 3:16 pm

This could be the reg pin out. I think the schematic is wrong on numbering?

Post by **jhsa** » Tue Jun 09, 2015 4:47 pm

I think the pinout for the 5V reg on the picture above is not correct. from left to right (or top to bottom on the picture above), it should be OUTPUT, GND, INPUT..

João

Post by **ShowMaster** » Tue Jun 09, 2015 6:57 pm

jhsa wrote:I think the pinout for the 5V reg on the picture above is not correct. from left to right (or top to bottom on the picture above), it should be OUTPUT, GND, INPUT..

João

I'll delete the reg picture. Maybe we can find the exact one to post. I'm not able to look at a board myself.
Ik, I see you posted a board with the busses marked, good!

Post by **jhsa** » Tue Jun 09, 2015 7:12 pm

Here it is. Pinout of the 78L05 regulator

ReSt · Post by **ReSt** » Tue Jun 09, 2015 9:30 pm

You may also have a look at these pictures
http://www.rcgroups.com/forums/showpost ... count=6779

Reinhard

hmarkvitz · Post by **hmarkvitz** » Wed Jun 17, 2015 5:18 pm

Let me clarify first I am a noob and have very little experience with electronics. I barely understand all these diagrams you guys put up. I tried checking the battery voltage on the board and the 5v voltage. I don't get readings on them although the battery is still connected. I was suggested in another thread that I connected the battery the wrong way. I am almost sure I didn't, but I'm not getting any readings on the two places I was told by "jhsa" to check. I don't know what to do with this... I found there is a fix to the battery reversal problem. I don't know where to get the components to try to fix it, or is anybody interested in buying this controller from me... It's practically new. I'm sorry I'm not that good with this, it seems so difficult. In a worst case scenario where I have to buy a new controller that will take the Frsky DJT, what would you recommend? The 9XR Pro, 9XR or something else?

Post by **jhsa** » Wed Jun 17, 2015 5:54 pm

Ok,
1- the module turns ON when you turn the power switch ON. That means the power switch has battery voltage and it is working.
2- When you power the radio using the usbasp, the radio turn ON normally. That means that the processor, LCD, etc are working.
3- You don't have any voltage on that regulator or the capacitor below as I indicated on the picture I have posted above. That means that there is no voltage coming from the power switch.

Please confirm that these 2 points above are correct.

Then, remove the backlight if you still have it connected. Plug in the original connector to the socket on the right side of the LCD connector.. Not the from the backlight, the original from the radio. Make sure there are no bent pins and it is fully inserted.
If you can, please post a good picture from the power switch board..

João

hmarkvitz · Post by **hmarkvitz** » Sat Jun 27, 2015 9:52 pm

jhsa wrote:Ok,
1- the module turns ON when you turn the power switch ON. That means the power switch has battery voltage and it is working.
2- When you power the radio using the usbasp, the radio turn ON normally. That means that the processor, LCD, etc are working.
3- You don't have any voltage on that regulator or the capacitor below as I indicated on the picture I have posted above. That means that there is no voltage coming from the power switch.

Please confirm that these 2 points above are correct.

Then, remove the backlight if you still have it connected. Plug in the original connector to the socket on the right side of the LCD connector.. Not the from the backlight, the original from the radio. Make sure there are no bent pins and it is fully inserted.
If you can, please post a good picture from the power switch board..

João

Joao, I'm sorry I haven't responded earlier. I have been busy with a lot of things and had to put my quadcopter on hold.

To respond to your questions:

1-The module does turn on with the power switch. it beeps and has a led on.
2-The transmitter does power on fine with the USBASP and I can see ER9X working on the screen.

I removed the LCD backlight completely and plugged in the original cable for the LCD. Nothing changed. Same thing, the module turns on but I'm not getting anything displayed on the screen. Here is a picture of the board.

Another thing I wanted to add is that I don't understand how I could have had a reverse battery polarity since the connector on the LIFe battery is as follow. Black connector with three holes in this order from left to right: black / red / nothing. If I connect it the other way around, the negative (black) wire will still be on the other side which I supposed is not wired to anything and the positive (red) wire will be again at the center.

chilskater · Post by **chilskater** » Wed Jun 17, 2020 2:49 pm

Hi,
i have the blank screen after replacing the motherboard. I fried mine when soldering it to,the solder pad fall off. So new motherboard came and i just replaced it. When i switch it on, the screen was blank with back light ON.

Any tips to solve?

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