Wednesday, December 29, 2010

A little mishap

I've been using erniebro's touch plate micro (on to zero the cutter before starting a job on the mill. It is really a time saver; no more jogging in small little steps of 0.01mm to zero by sight of all the 3 axes.

On Christmas night, it stopped working. Touching the 2 crocodile clips together (my "probes") didn't lit up the Touch Test LED in the Probe section. Couldn't figure out what happened after checking around for a while. So went back to manual zero'ing to complete the facing job to prepare the stock for the z axis mounting adapter for the A2Z leadscrew.

I kept thinking about what could have happened for the past 2 days and decided to check for connectivity of all the wires leading to the probes. Using a multimeter set to continuity mode, I probed the DB9 cable, the DB9 breakout board, and the wires connected to the crocodile clips. All perfect, nothing broken. Then I started connecting them part by part while testing continuity after each part was assembled. No problem found. Strange...

I decided to open up the controller box and look at what I've found:

The little wire (blackish one across the 4 pins on top) came loose from its soldering joint.
The 4 pins on the top row at the back of the DB9 socket is soldered together with a piece of hard wire. The black wire you see in the pic is the ground.

I took out my trusty made in China soldering iron to try to heat up the hard wire to melt the solder underneath it so that they'll stick.  Instead, the black wire came off the slot.  Couldn't seem to heat up the hard wire enough for the solder to stick.  Quite some time was spent trying to remove the solder from the slot using a soldering pump and trimming of the black wire to fit the slot.  Gave up using the hard wire.  A piece of jumper wire was stripped, laid across the 4 pins, and the joints soldered.  Ran some test before closing the cover to make sure it works.

Jumper wire soldered in place and excess trimmed off.

Now I'm back in business!

I've done some further work on the A2Z leadscrew hardware for the z axis.  Will try to post them up tonight if I've the time.

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