If you enjoy our forum, why not join us? :) Login removes all the ads too! Click here to register in a few simple steps

Login to remove this ad | Register Here
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
DemonCore Continuity Check (before I fry something)
#1
OK, another DemonCore v2.3 question for you electronics wizards (hmm, should be badge for that....)

According to DemonCore docs, I can use any unused 5V switch pad to draw power for my FC. So I'm tapping the 5V pad next to the 12V bridge/switch that I soldered for the VTx.



Now I had a bit of trouble with the soldering, but after I was done, I inspected the separation, ran an exacto-blade between the pads to make sure I had no solder bridge between the 5V connection and the 12V switch, inspected again with a small magnifying glass, and I think the separation is fine.

However, to be safe, I checked for continuity between the two with my multimeter.  My multimeter doesn't have a buzzer - so I was just hoping to see infinite ohms between the two. Well it was high, but not quite "infinite" - I'm reading about 3100 ohms between any 5V pad and any 12V pad.  Now I had no reason to check continuity before soldering, and I'm no whiz on voltage regulators, but it worries me.  Should it?  Or is this normal?

EDIT: It also just occurred to me - did I just ruin my PDB by testing it like that?

Thanks,
Scotty
#2
1. looks like you put a bit too much solder on those pads Smile
2. I have the same PDB, I also run 5V on OSD, what I did was i make a cable that split the 5V output on OSD to power both FC and OSD
3. I just checked on mine as well, and I can confirm between the 5V and 12V pad there is around 3Kohm resistance, same in your case.
4. no it won't ruin the board measuring resistance Smile
Don't be a LOS'er, be a FPV'er :) -- Blog - Facebook - Instagram - Twitter - Google Plus
[-] The following 2 users Like Oscar's post:
  • sloscotty, KonradS
Reply
#3
I just ran continuity test between 5v and 12v pads on 3 of my boards (different earlier versions of Core, one of them is unsoldered). BUT I remember that when checking that on V2.3 I also had strange readings. Can't check that now as it's buried inside the quad and I have no time to disassemble. Can do it in the evening.

EDIT: Oscar was first again ;p
Find me on Youtube and Instagram. I currently fly: NOX5, NOX5RAirblade Assault 130 and drive a scrap RC car
[-] The following 1 user Likes KonradS's post:
  • sloscotty
Reply
Login to remove this ad | Register Here
#4
(14-Aug-2016, 11:38 AM)Konrad Stepanajtys Wrote: I just ran continuity test between 5v and 12v pads on 3 of my boards (different earlier versions of Core, one of them is unsoldered). BUT I remember that when checking that on V2.3 I also had strange readings. Can't check that now as it's buried inside the quad and I have no time to disassemble. Can do it in the evening.

EDIT: Oscar was first again ;p

That is why Oscar is the "Posting Freak", always first, He beat you and I...sheeesh
My youtube channel

[-] The following 1 user Likes BigglesFPV's post:
  • sloscotty
Reply
#5
I don't think it is uncommon to get readings like that  when you have two power supplies on the same board sharing common grounds.
"Damn the torpedoes!!!  Full speed ahead!!!"
[-] The following 1 user Likes sirdude's post:
  • sloscotty
Reply
#6
(14-Aug-2016, 11:36 AM)Oscar Wrote: 1. looks like you put a bit too much solder on those pads Smile
2. I have the same PDB, I also run 5V on OSD, what I did was i make a cable that split the 5V output on OSD to power both FC and OSD
3. I just checked on mine as well, and I can confirm between the 5V and 12V pad there is around 3Kohm resistance, same in your case.
4. no it won't ruin the board measuring resistance Smile

Whew!  Thanks for checking Oscar!  And as for the solder - you should have seen it before I cleaned it up Big Grin (Now that really big blob at the top was already there.....)

(14-Aug-2016, 11:38 AM)Konrad Stepanajtys Wrote: I just ran continuity test between 5v and 12v pads on 3 of my boards (different earlier versions of Core, one of them is unsoldered). BUT I remember that when checking that on V2.3 I also had strange readings. Can't check that now as it's buried inside the quad and I have no time to disassemble. Can do it in the evening.

EDIT: Oscar was first again ;p

(14-Aug-2016, 11:46 AM)BigglesFPV Wrote: That is why Oscar is the "Posting Freak", always first, He beat you and I...sheeesh

(14-Aug-2016, 12:06 PM)sirdude Wrote: I don't think it is uncommon to get readings like that  when you have two power supplies on the same board sharing common grounds.

And thank you all for jumping to my rescue so quickly - I "like" you all for being like that!
Reply
Login to remove this ad | Register Here
#7
If there are capacitors connected in parallel on the PDB, you will charge them with your multimeter when doing a continuity test. My guess is that is what you are seeing

[-] The following 3 users Like oyvinla's post:
  • BigglesFPV, KonradS, sloscotty
Reply
#8
Thanks oyvinla! Great video - it's nice to know a possible reason!
Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  Help DemonCore PDB on 3S sloscotty 4 738 10-Aug-2016, 01:27 PM
Last Post: BigglesFPV