GlassKnees
Well-Known Member
If you've spent any time in this hobby, building or modifying your aircraft, you already know what I'm talking about - buying parts online can be a real crap shoot. But for most of us, the lack of hobby shops that stock the things we need near where we live leaves us little choice.
Just yesterday, I was reminded of this fact in a rather painful way. On Jan 2nd I ordered a replacement GPS module for a quadcopter I was building from spare parts as well as others salvaged from a crash. I am a 3DR bigot and use APM 2.6 flight controllers with external GPS/Compass. My compass was defective and needed replacement but was unable to find a suitable replacement until I found on Amazon, a ckt board that looked like it had the same footprint as the board inside my 3DR housing. The price, around $20 surely beat the $80 that 3DR charged (and is unavailable), so I pulled the trigger and ordered it.
The unit finally arrived from China yesterday (no doubt held up by one of the president's executive orders), and I was eager to install it:
The defective unit is the green one on the right.Aside from the color of the board and the orientation of the U-blox GPS chip, can you tell any difference between the two?
The board fit inside the plastic case just fine, but when I tried to plug the mag compass wires, I discovered that the onboard plug didn't quite line up with the opening on the case. I thought I could remove the board, run the wire through the opening and then plug it in and re-insert the board back in the case - big mistake. The plug popped off the board:
A close visual re-examination of the two boards showed that the plug for the mag compass is slightly offset. The only way to make it work is to cut the opening in the case on one side.
This is just one of several challenges I've had to face. Sometimes you need to replace a part and you simply cannot find it and you have to take a chance on another part that's not quite the same. I experienced this when I lost the propeller washers to my Tarot 4006 620kv motors. I searched to no avail; I even tried to contact Tarot, both in China as well as the U.S. distributor but got no replyl from either. Finally, I found, what looked like a suitable replacement - T-Motor washers from Helidirect.com.
The problem was that although the hole spacing is the same, the T-Motor washers are smaller than the Tarot counterpart. Here is an image of the Tarot washer:
And here is the T-Motor:
As it turned out, I lucked out - despite the smaller diameter, these t-Motor washers work just fine.
Most of the time, when you're searching for something, the specs simply do not provide the information you need to make an informed decision, so you are left with rolling the dice and hoping for the best. I'm sure that most of you have lots of spare parts sitting around - stuff that you ordered only to find that you can't use them.
Just yesterday, I was reminded of this fact in a rather painful way. On Jan 2nd I ordered a replacement GPS module for a quadcopter I was building from spare parts as well as others salvaged from a crash. I am a 3DR bigot and use APM 2.6 flight controllers with external GPS/Compass. My compass was defective and needed replacement but was unable to find a suitable replacement until I found on Amazon, a ckt board that looked like it had the same footprint as the board inside my 3DR housing. The price, around $20 surely beat the $80 that 3DR charged (and is unavailable), so I pulled the trigger and ordered it.
The unit finally arrived from China yesterday (no doubt held up by one of the president's executive orders), and I was eager to install it:
The defective unit is the green one on the right.Aside from the color of the board and the orientation of the U-blox GPS chip, can you tell any difference between the two?
The board fit inside the plastic case just fine, but when I tried to plug the mag compass wires, I discovered that the onboard plug didn't quite line up with the opening on the case. I thought I could remove the board, run the wire through the opening and then plug it in and re-insert the board back in the case - big mistake. The plug popped off the board:
A close visual re-examination of the two boards showed that the plug for the mag compass is slightly offset. The only way to make it work is to cut the opening in the case on one side.
This is just one of several challenges I've had to face. Sometimes you need to replace a part and you simply cannot find it and you have to take a chance on another part that's not quite the same. I experienced this when I lost the propeller washers to my Tarot 4006 620kv motors. I searched to no avail; I even tried to contact Tarot, both in China as well as the U.S. distributor but got no replyl from either. Finally, I found, what looked like a suitable replacement - T-Motor washers from Helidirect.com.
The problem was that although the hole spacing is the same, the T-Motor washers are smaller than the Tarot counterpart. Here is an image of the Tarot washer:
And here is the T-Motor:
As it turned out, I lucked out - despite the smaller diameter, these t-Motor washers work just fine.
Most of the time, when you're searching for something, the specs simply do not provide the information you need to make an informed decision, so you are left with rolling the dice and hoping for the best. I'm sure that most of you have lots of spare parts sitting around - stuff that you ordered only to find that you can't use them.