LibrePilot Forum
Development => Hardware => Topic started by: paulj on August 02, 2020, 07:18:53 pm
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Hi all! I have been rebuilding my quad following the catastrophic failure of a pack (ie a fire), and having got it all back to gether I have managed to fry the main port connector on the revo board. The board is still good - the pin melted, but when I check the board voltages it s still delivering a nominal 5v. What is the specification of the jst plug used on the revo? I would like to replace it by soldering in a new one.
- Why did the pack fail? The voltage regulators are mounted through the bottom plate, and the tape I put on had degraded allowing the voltage regulator to short out the incoming voltage on wet grass. The pack let go pretty quickly. As part of the rebuild, I have replaced both the 5v and 12v regulators, and insulated the contacts with hot glue.
- In case you want to know what I did wrong to fry the revo plug - I connected a balance lead to the Frsky voltage monitor the wrong way round (I know - stupid mistake, not thinking!!). The receiver and the voltage telemetry monitor happily passed the voltage through to the revo without any damage to them, and luckily the pin in the plug acted like a fuse, and blew pretty quickly!
In the mean time, I will re-equip the quad with a sparky 2 I have had sat around for a couple of years!
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JST-SH is what you want. As I recall, it is the 1.0mm pin spacing that you want. Make sure of the pin count and spacing. If you can't find them at your favorite place, I know that eBay has them.
Verify pin spacing with a ruler (but not on the male pins? too much parallax to see well). If you align the first feature with any mm, then they should all perfectly align with other mm's on the ruler.
Just an opinion: Hot glue... I'd cover it with a plastic plate held with nylon screws and nuts if "landing damage" :) seems possible? Glue like stuff could be scratched off by a rock, and glue makes repair more difficult?
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Hi Cliff - thanks for that!
Regarding the vulnerable contacts of the voltage regulators - I am going to cover the bottom plate of the quad with adhesive 2mm foam - this will protect them in the event of future contact with the ground. The bottom plate of the quad is basically a PCB power distribution board - all the circuitry is soldered directly to it. It is very tidy, but I am not sure I would use it if I built the quad again - it was a real bitch to solder, as the heat is being drawn away very quickly from the iron, and the biggest iron I have (35W IIRC) was not really big enough!
I'll go and have a look for the connectors, following your very helpful tips!
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I have a 50 year old Weller 325 watt soldering gun that is the best you can get for that (IMHO). 325 watt (they only make 275 watt now, but 275 is just as good) heats quickly and gun means you only heat it enough for the current joint so you don't overheat the tip. There are some ~ 200 watt guns that probably work fine too for what we do.