tantalum capacitor

[TechVic-1]

Shouldn't the tantalum capacitor be solder to output and ground, not input and ground as you did. The document on L4941BDT l4941-973941.pdf What I can see tantalum should be solder to output

[gc9n]

You can do it like this yes, i made the oposite because i saw a finished circuit with this regulator and it was like i did it. But you can do it like datasheet says

[TechVic-1]

Okey Do you know what size on the ceramic capacitor you used, does it matter? I have a 4.7 microF tantalum and 22 nanoF ceramic or 2.2microF ceramic, which ceramic should I use?

[gc9n]

i dont really know what are the specs from the Ceramic , i know that the ceramic can handle lots of volts. so i just picked the right size (physical dimensions) for me. pick the one that can handle the most

[gc9n]

I am also working on the cables, i made it as clear as possible, the osd will be plug in and out for firmware updates, i will report soon with pics

[robert-hoffmann]

the datasheet says 1 ceramic 0.1µf on the in pin & 1 electrolyte 22µf on the out pin

[gc9n]

no problem , i just followed this circuit. https://static.rcgroups.net/forums/attachments/1/7/2/2/3/6/a4459750-142-IMG_6203.jpg as you can see the input is not a tantalum

[TechVic-1]

On that picture the tantalum is on the input pin, both regulators are connected to it. Data sheet says tantalum on output pin so I did it that way but My sma connector is getting really hot like really hot, so I desoldered the regulator and restored the original 5v from goggles and the heat is gone. Maybe the tantalum should be on input pin?

[robert-hoffmann]

@Freakshowdevil what do you mean your SMA connector is getting hot ? How did you power it ?

[TechVic-1]

The sma connector on the module is getting hot, barely touchable. I am powering it with L4941BDT same as gc9n.

[gc9n]

you open the goggles and you replace the reg inside?

[gc9n]

What goggles do you have and what is the reg inside them?

[TechVic-1]

No, I moded exactly as u did, using a L4941BDT on the realacc module. Dominator HD v2 never opened it up so can't say what regulator is inside. When I discovered that the sma was burning hot I striped all mods (L4941BDT and osd) and restored realacc to original.

[TechVic-1]

By sma connector I mean antenna connector

[gc9n]

Now i get it, no mine is cold, ambient temp, both sma.lets take it from start , what baytery did you use? Did you connected to goggles? Did you cut the vcc pin? Any short circuits?

photos?

[TechVic-1]

Using standard battery, Vcc pin cut, did exactly as you expect that my Realacc is the split version and tantalum on output pin. No pictures, the realacc is restored to original and now it's not hot anymore, will do the mod again starting with the regulator and tantalum on input pin instead to see if that makes any difference. Maybe one of my cap was too small, should be nice to know the size of your cap (the ceramic)

[gc9n]

dont worry about the ceramic. the other is important.

[TechVic-1]

Maybe it is potential different on the negative side that is the problem. My guess is that the problem lays with the caps but can't get my head around why only that long SMA "antenna" connector got heated up and nothing else, but potential different can do that hmmmmm. Will do some more testing after Xmas.

[TechVic-1]

A side note on OSD, rssi was visual on OSD but not the battery voltage and the fatshark buttons didn't work either. Maybe I did some thing wrong when setting minimosd up, following oscarliangs tutorial.

[TechVic-1]

Your cable schematic and the pic on how you did it, pins on minimosd are not same!! Maybe it's why mine didn't work properly, I followed the schematic. What I can see is that on the schematic you're using small pad to the left of the 5v pad but on the pic on how you did it you're using the small pad where the 0 mark is on the atmega chip

[gc9n]

YES You are correct i made this mistake, this is the correct connection diagram , and down there is a new photo of the minim osd

[gc9n]

This mistake, is the reason for Buttons response from fatsharks, and Battery feedback. i think there is no other relation to the "warm" sma. Please redo and correct this mistake , everything sould work

[robert-hoffmann]

Nice clean cabling of the minim there :-)

[TechVic-1]

Nope still no battery indication on OSD and Fatshark buttons don't work. RSSI works and the heat is gone, did put a bigger cap.

[gc9n]

the connections are correct the software is the latest? for both module and osd?

[gc9n]

the rssi you see is changing values (is alive?)

[TechVic-1]

Yeah everything downloaded today, yes rssi is changing value when I hold my hand in front of the antenna. No battery goggles showing up on OSD like in your video.

[gc9n]

can you measure voltage in batt1 pin and ground?

[TechVic-1]

7.66V batt1 and ground

[gc9n]

if i told you that i downloaded the hex files. and it was not working to me either!!, buttons and rssi

i uploaded a wrong version of OSD.. HOLD ON....

[gc9n]

ok i re upload the final version, please check now (Upload to minimosd) https://github.com/gc9n/rx5808-Diversity-RealAcc-Compatible/blob/master/PolyPhemus.ino.hex

[TechVic-1]

No problem mate, shit happens 😂 I will try in a bit

[TechVic-1]

Rssi, fatshark buttons and battery osd works like a charm mate. Great work

[gc9n]

ahhhh i am happier from you!

[TechVic-1]

Only one thing with osd that I noticed was that not all of the text in under menu's don't appear as they do on the oled

[gc9n]

I know . I didnt add the find model yet!

[gc9n]

now make a review!