Showing posts with label repair. Show all posts
Showing posts with label repair. Show all posts

Thursday, September 19, 2013

Repair Terminals on Hobby DC Motors.




A lot of people think the motor is destroyed when the fragile brass terminal connector that connects the wire to the motor's brush tears off. It happens all the time from wear and tear or even from disconnecting a terminal plug when they are brand spanking new.  Most times there aren't replacements available for a darn good motor that has years of service ahead of it.
  Here is a quick and dirty fix which is not only a temporary fix, but could be way more secure than the original tab ever was.  First, most often it breaks off at the motor frame and there is no metal to solder anything to. If you are lucky, you have a small gap wide enough to insert a couple strands of thin (stripped 24 gauge or smaller) solid copper wire.  But most there will be no way to clean the existing metal.  Lets change that! (If you can get away without drilling, don't drill! If you get to aggressive, it can destroy the brush terminal!) Take the smallest drill bit you can find, most often that will be 1/16th of an inch. If possible, go even smaller with specialty bits.  We're not drilling through the case, so take it slow with a hand drill or drill press.  I used a hand driven twist drill since you just want to open up/clean the area beside the motor's connector enough for a couple pieces of thin copper wire.
You want to drill straight down beside the existing brush/terminal connection. A power drill will drill a hole too quick and chew the brass brush to bits. I fit 4 small pieces of solid strand copper wire beside the broken brass terminal. Then solder the brass and copper together making a new solid tab. That's it.  Test your motor and you are good to go!
This motor required that both terminals be repaired. Works as good as new!
If you notice the circuit board in the upper photo with 8 mosfet and close to 30 transistors. Our new dual 45 amp motor controller for the upcoming robot! Lots of good stuff coming, stayed tuned!



Monday, April 29, 2013

Destroyed the SD card socket in my Raspberry Pi.




Micro SD adapter mounted in the Raspberry Pi

When it rains,  it poors! For the first week, I have been chasing a bug on the Raspberry Pi. Where keystrokes from the USB keyboard are missing or are duplicated continously .  This bug is caused by low or no power on your USB hub. Since I have a 2 amp powered hub, I have tried changing devices looking for something that was shorted or power hungry that could be causing it.  The problem was intermittent, so I would have to wait for it to occur to try and solve it. Today it happened, so I replaced the keyboard (yet again) and started wiggling wires. I pulled too hard and yanked it from its case while the sd card was installed. The Raspberry Pi came out of the case ripping the Sd card mounts clips off.  It will no longer hold an sd card. Without an sd card it would not boot!