Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 So I recently decided to give my ZMR250 an upgrade. I've installed 2205-2300 motors, 20A ESCs and decided to add a PDB with 5/12v regulators so I can go to 4S. Having re-wired everything I'm very disappointed to find that something is wrong. The PDB only gives out ~2-3v on both the 5v and 12v outputs. I can't visually see an obvious short circuit. Basic tests with a multimeter seem ok, no resistance between all GND points, infinite resistance between GND and +VE, infinite resistance between GND and all signal pins, infinite resistance between 5v/12v outputs. The only slightly off thing is a resistance between +VE terminals of the various ESCs? Any ideas of how/what I should test to try and identify the issue? I hope the board isn't a dud. Heartbreaking after all that soldering! ![[Image: 6F7BE0BD-69C2-4FED-BD2A-EA54463BB524_zpswwrrfppa.jpg]](http://i1330.photobucket.com/albums/w572/JBFUK/RC/6F7BE0BD-69C2-4FED-BD2A-EA54463BB524_zpswwrrfppa.jpg) ![[-]](https://intofpv.com/images/collapse.png) • Posts: 125 Threads: 12 Likes Received: 86 in 45 posts Likes Given: 52 Joined: Jan 2017 Reputation: 8 First test for me in cases like this is to desoldere everything from the 5V and 12V output pad. After that you can check the Voltages without a Load. When the Voltages appear to be normal then there is a high chance that something was wired the wrong way or that there was somehow too much load on the outputs. If it's still isn't going to the normal Voltage you have an error somewhere on the board. Either it's a tiny solder bridge somewhere or an actual manufacturing error. I had the exact same PDB and had a Problem with my 5V output. After I checked everything I decided to desolder the 8Pin Regulator IC only to find out that one of the legs was broken which was not visible under the microscope prior to desoldering. Here is my post about that http://intofpv.com/t-it-s-happening-mart...4#pid19874 I like turtles • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 He doesn't have anything soldered to the 5V and 12V outputs! • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 (10-May-2017, 09:47 AM)Apicalis Wrote: First test for me in cases like this is to desoldere everything from the 5V and 12V output pad. After that you can check the Voltages without a Load.
When the Voltages appear to be normal then there is a high chance that something was wired the wrong way or that there was somehow too much load on the outputs.
If it's still isn't going to the normal Voltage you have an error somewhere on the board. Either it's a tiny solder bridge somewhere or an actual manufacturing error.
I had the exact same PDB and had a Problem with my 5V output. After I checked everything I decided to desolder the 8Pin Regulator IC only to find out that one of the legs was broken which was not visible under the microscope prior to desoldering.
Here is my post about that
http://intofpv.com/t-it-s-happening-mart...4#pid19874 Oh man, so you had a very similar issue by the sound of it. I'm pretty sure I don't have any soldering errors and the only thing connected to the 12V output is a lead with a JST connector. Guess there's nothing to do but de-solder everything and test again. So annoying if it's a faulty board. Lesson learned is I should have hooked up power and tested the thing before soldering everything else. • Posts: 125 Threads: 12 Likes Received: 86 in 45 posts Likes Given: 52 Joined: Jan 2017 Reputation: 8 (10-May-2017, 10:00 AM)unseen Wrote: He doesn't have anything soldered to the 5V and 12V outputs! DONT YELL AT ME! (10-May-2017, 10:02 AM)JBFUK Wrote: Oh man, so you had a very similar issue by the sound of it.
I'm pretty sure I don't have any soldering errors and the only thing connected to the 12V output is a lead with a JST connector. Guess there's nothing to do but de-solder everything and test again. So annoying if it's a faulty board. Lesson learned is I should have hooked up power and tested the thing before soldering everything else. Yeah I have desoldered and resoldered many things on my quad :/ Doesn't seem to be the appropriate quality control done here on these PDBs. But it's definetly weird that both of your outputs have that problem. Usually the 7812 (12V Regulator [the fat IC]) is a very simple device. It just needs VBAT in, some caps on in and out and it works perfectly fine. Very odd scenario that both regulators have the same issue. I like turtles • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 (10-May-2017, 10:00 AM)unseen Wrote: He doesn't have anything soldered to the 5V and 12V outputs! There are two sets and I do have two wires soldered to the 12V output but only a JST connector on the end, VTX etc is disconnected. Sounds like probably a dud board, don't think I'll be buying Matek again. • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 (10-May-2017, 10:10 AM)Apicalis Wrote: Very odd scenario that both regulators have the same issue. Very odd, and, on one occasion of powering on the 5v LED was not on, then it flickered a bit, then after a while came on. I was thinking maybe a bad IC. Once I de-solder everything and remove, after testing, I might give the whole thing a blast with the heat gun. • Posts: 125 Threads: 12 Likes Received: 86 in 45 posts Likes Given: 52 Joined: Jan 2017 Reputation: 8 IMPORTANT Question!
What Battery did u connect? If you used a 3S Lipo the Voltage was likely too low for the 12V regulator to function properly and you "just" might have a dead 5V regulator like I did. I like turtles • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 (10-May-2017, 10:11 AM)JBFUK Wrote: There are two sets and I do have two wires soldered to the 12V output but only a JST connector on the end, VTX etc is disconnected. Sounds like probably a dud board, don't think I'll be buying Matek again. Sorry, my mistake. • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 10-May-2017, 10:40 AM (This post was last modified: 10-May-2017, 10:49 AM by JBFUK.) (10-May-2017, 10:14 AM)Apicalis Wrote: IMPORTANT Question!
What Battery did u connect? If you used a 3S Lipo the Voltage was likely too low for the 12V regulator to function properly and you "just" might have a dead 5V regulator like I did. Well, it was 3S, and I plan to use 3S with this setup as well as 4S (I only have 3S at the moment). The PDB manual says I can use 3S but the 12V output will be -1V under the input voltage which for all my 12v components is fine.... Another potential issue looming is I noticed one of the motors seems to have less magnetic resistance to turning than the other three  With all the messing around, upgrades, hassle, I should have just brought a Vortex 250 and been done with it. • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 10-May-2017, 12:13 PM (This post was last modified: 10-May-2017, 12:16 PM by JBFUK.) http://www.radioc.co.uk/Matek-PDB-XPW-p/7221.htm http://www.mateksys.com/?portfolio=pdb-xpw#tab-id-2 BEC 12V output Designed for Video TX or FPV camera with linear regulator. The battery should be 4~5S LiPo (13~21V DC) .... BEC 12V @ 3S LiPo Output voltage= 3S LiPo voltage -1V So note very clear regards the 12V output on 3S. What happens if you hook up a 3S to yours do you get lipo -1v on your 12V output? • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 Removed everything, same result. Weirdly I get ~2.5v on both the input and output legs of the 12v regulator. • Posts: 125 Threads: 12 Likes Received: 86 in 45 posts Likes Given: 52 Joined: Jan 2017 Reputation: 8 (10-May-2017, 12:13 PM)JBFUK Wrote: http://www.radioc.co.uk/Matek-PDB-XPW-p/7221.htm
http://www.mateksys.com/?portfolio=pdb-xpw#tab-id-2
BEC 12V output
Designed for Video TX or FPV camera with linear regulator.
The battery should be 4~5S LiPo (13~21V DC)
....
BEC 12V @ 3S LiPo
Output voltage= 3S LiPo voltage -1V
So note very clear regards the 12V output on 3S. What happens if you hook up a 3S to yours do you get lipo -1v on your 12V output? Sry I don't have any 3S batteries. But it makes sense what the datasheet says. In my expirience these LM78XX regulators usually don't just die when you go below the recommendations (10-May-2017, 03:02 PM)JBFUK Wrote: Removed everything, same result. Weirdly I get ~2.5v on both the input and output legs of the 12v regulator. Well that would've been my next guess. Since you told me that you have the same voltage on the 5V and the 12V regulator there must be something wrong on the PDB or the wiring that feeds the battery voltage. Can you take a picture of the board how it looks right now? Can you measure the resistance from the negative battery lead to the heatsink of the 12V regulator? Do you have an oscilloscope to look at the output voltage? Maybe it's oscillating. I like turtles • Posts: 34 Threads: 1 Likes Received: 12 in 8 posts Likes Given: 8 Joined: May 2017 Reputation: 1 Those solder joints in the pick don't look the greatest but have you tested the voltage when connecting a 4S?
No need for all that hot glue in the future btw.. • Posts: 78 Threads: 14 Likes Received: 13 in 9 posts Likes Given: 1 Joined: Nov 2016 Reputation: 0 Ditched it, brought a Kombini, all good. • |
