Hi, 

pic : https://photos.app.goo.gl/JmqBizQD2s8tNYT97

In the pic above you can see TinyHawk S VTX, with leftoverS of solder on the signal and ground pads.

After some video disruptions, I replaced the Antenna, but I still had video disruptions, So I de-soldered them, and ran a connectivity check and found out that they are connected.

Is this a common problem ?
Is there some soultion ?
Is my VTX R.I.P ?

Thanks

Doronba

The ground connection pad and and the active connection pad on the VTX where the antenna is soldered to shouldn't have any continuity between them so something is definitely wrong there.

So that was my problem.
And now for the solution :

I got a Rush Tank Tiny (https://www.getfpv.com/rush-tank-tiny-5-...audio.html )
What should I check for if I would like to use it as a replacement for the stock VTX ?
The Rush Tank Tiny can transmit up to 350mW, but originally the Tiny Hawk transmitted only in 25 mW, what does it mean ?
Probably something about power in the circuits ? maybe over heating problems ? Should I limit the Rush only to 25mw ?
(I am a noob, so I am not sure what to ask exactly and what I should check for before I burn my Tiny)

If you fit the Rush Tank to the TinyHawk you can just wire it up in place of the existing VTX. It will just be a simple swap over. You will also need to heat shrink it or insulate it some other before zip tying it to the FC. If you are only flying around your apartment then I would set and limit the VTX to 25mW so there is no risk of it overheating because there isn't going to be a lot of airflow in an enclosed apartment. You shouldn't need more than 25mW in a small flying area, unless your apartment is huge.

Great, I am going to do it today, I must start flying.....

About the connections :
The original stock VTX connection legs, are : 3.3v, grund, smart audio & signal
The rush works on 5v.
I see that there are two free pads on the FC, marked 5v, BUZ-.
So,  I was thinking that I could use that 5v pad instead of the 3.3v leg for power, right ?

BUT

I became a little worried after I read a thread about the Tinyhawk free style, saying that the 5v pad should not be used to draw a lot of power as the VTX needs, because it will fry the FC with time,
here is a pic of the exact post : https://photos.app.goo.gl/gEz6upznifPWp3QY7
and here is the whole thread : https://oscarliang.com/tinyhawk-freestyle-micro-quad/
But the Rush tiny is the only tiny VTX available to me at the time... So, can I use it on the Tinyhawk s ? (Important info : I use only 2S lipos, So I have the voltage)

And just of curiosity, 
If I can use this 5v pad for the VTX, will I be able to connect to it also the positive leg of a buzzer, or it's better not to ?

Here are the connections options of the Rush :
https://cdn.getfpv.com/media/wysiwyg/pro...59d0cg.jpg

If you are saying that I can use the 5v pad on the FC, then, the GND will come from the original GND leg,
I also think that I understand that the DATA is connected to the Smart audio leg,and that I should connect the Video-out to Vtx pad. (please tell me whether I am right or wrong)
according to diagram in the bottom of this pic : https://photos.app.goo.gl/sLE4kAHyp1kicZPk8

I know that I am asking a lots of questions, but it's better than be sorry after...

Thanks for your answers, very cooperative, concise  and helpful.

OK, first of all the VTX on the TinyHawk takes 5V according to the manual, so you can just use the original 5V source from there the VTX pins connect to the main board. See the image below. You can double check that by powering up the TinyHawk and measuring what voltage you are getting on that pin with a multimeter. Unless of course you already did that and you found it to be outputting 3.3V. It wouldn't be the first time that information in manuals is incorrect.



I'm not sure why the Rush Tank Tiny would overload the TinyHawk FC if connected to 5V, especially if you keep it on a low power output of 25mW. After all, the stock VTX is running 25mW from a 5V pad so it's no different. Maybe that user just had a bad FC board. Unfortunately I can't find any power consumption specs on the Rush Tank Tiny at the moment. I guess roll the dice and take a chance. You don't seem to have many other options at the moment.

Regarding using 1S or 2S LiPos, it will make no difference because there will be a 5V voltage regulator on the board that will either step up or step down voltage to 5V regardless of whether you use a 3.7V 1S LiPo or a 7.4V 2S LiPo.

As for connection, below is the wiring diagram you want to use. It is just a direct connection of 4 wires from the Rush Tank to the FC. You just use the same 4 connection points that the original VTX is connected to on the standoff pins, so it's a straight swap (assuming the 5V pin is actually outputting 5V). Your camera is connected to the FC already so you don't use the 3 pad on the other side of the Rush Tank Tiny.

OK,
I took the stock VTX off,
Soldered the wires to the Rush tiny,
I did realize that the positive leg is 5v indeed. Great tip of your side.
So, for learning purposes, where is the regulator in the VTX ? I am not an advanced elctronician obviously, but very fond to learn.
Am goin' to solder everything and then upload the pics.

Afterwards, do I have to define something in Betaflight before going to fly ?
I saw this post about what to set when replacing VTX : https://www.rcgroups.com/forums/showthre...st43633355
I do want to limit the VTX to 25mw, so I wont do silly mistakes, so what should i change in these commands ?
In previous thread about the same tinyhawk, You mentioned something about Betaflight version, I think mine was 4.0...blah blah blah.. no channels tables or something like that... I am not sure what to ask, but is there any command I should type in the CLI and replace there ?
thanks, goin' to solder... and take pics...

The 5V buck-boost regulator will be on the FC, not the VTX. Without detailed pictures of the FC board, part of which is covered by the VTX itself, it will be difficult to determine which component is the 5V regulator without having a physical board in front of me, but it will look something like the one in the 3rd picture (with the 10 labelled pins and circuit trace lines) of the following post...

https://intofpv.com/t-eachine-trashcan-7...8#pid58198

The Rush Tank Tiny uses SmartAudio just like the original VTX so there is nothing to change for the UART protocol. Just make sure the VTX power setting is set to level 1 (for 25mW) in the CLI, but it was already set to that previously so unless you changed it, it should still be fine. No VTX tables are needed if you are running a version of Betaflight prior to 4.1.x which you are, because you're on 4.0.0.


So as long as the power is all set, then it should be pretty much just "plug and play"

OK,
No smoke, no continuity, i am on betaflight, and this is the get vtx output :
----------------------------------------------------
# get vtx
osd_vtx_channel_pos = 404
Allowed range: 0 - 15359
Default value: 234

vtx_band = 5
Allowed range: 0 - 5
Default value: 4

vtx_channel = 8
Allowed range: 1 - 8
Default value: 1

vtx_power = 1
Allowed range: 0 - 4

vtx_low_power_disarm = OFF
Allowed values: OFF, ON, UNTIL_FIRST_ARM

vtx_freq = 5917
Allowed range: 0 - 5999
Default value: 5740

vtx_pit_mode_freq = 0
Allowed range: 0 - 5999

vtx_halfduplex = ON
Allowed values: OFF, ON
---------------------------------------------------------
it seems like what was before i replaced the vtx, is it normal ? i suppose that it is the FC job to change freqs and other stuff..

1. What about : vtx_low_power_disarm = OFF, what does it mean ? does it mean that when battery is in, but quad is not armed, the VTX still transmits ? i suppose thats good to help finding it after it fell.

2. What about these lines :
vtx_power = 1
Allowed range: 0 - 4
Does 0 = 0 transmission ? / pit mode ?

3. how can i limit the power to 25mw, as long as this vtx is the tinyhawk, not giving me the option to change it by mistake via the smart audio ?

Yes, with SmartAudio enabled, the FC is in control of the power and frequency settings on the VTX,

1. The vtx_low_power_disarm setting is only useful where you want the power to stay at it's lowest setting when disarmed (so the VTX doesn't overheat when the quad has no airflow), then when you arm it will change the power to the normal preset power level. Your preset is the lowest setting (25mW) anyway and will remain on that low power level, so the low power disarm setting is not useful to you. So just leave it OFF. Whether you are armed or disarmed, the VTX will be outputting 25mW unless you enable pit mode or you unplug the LiPo.
   
   
2. A power level of either 0 or 1 both equate to the lowest power level . In your case 25mW.
   
   
3. You can't lock or limit the power settings on the VTX unfortunately. If you have no reason to change it from 25mW then just be extra careful not to change the power level setting value in either the goggles CMS menu or on the Betaflight VTX tab.
   

Understood, Done, Seems working.
Being a noob, I thought I will easily fit the VTX inside, It wasn't that easy for me, so I gave up and located it in the 'cradle', below. I hope that it won't get hurt on crashes, the battery should protect it.
here are the pics. sorry for the quality,
https://photos.app.goo.gl/heBzuPmT6jbw8XUe8

I did wonder if you would get the Rush Tank Tiny inside the canopy. I guess not. As long as it works I guess it's your only real option.

It looks like you have left the standoff pins in place and have just soldered to the top of them. If the wires from the VTX aren't too fat I would probably remove the pins and solder the wires through the holes that the pins came from. If not then pit some heat shrink tubing over the wire where it is soldered to the top of the pins because there looks to be a bit too much exposed wire there which is a bit risky in case they accidentally touch together.

So I assume it's now working just fine?

YESSS!!!!
it flyes and transmits video HOORAY.
this was my first quad repair project, and i have learned a lot.
i did it with the most improvised equipment, so, that's why i did not cut the standoffs.
soldering the wires directly to the holes is a great craftmenship, and will be my next project when i have to reopen this little beast.
for now, i want to FLLLYYY
thank you very much for the support man.
doornba