Wednesday, 28 August 2013

Caught in the Act

My wife thought the house was strangely quiet this evening, so she came upstairs and caught me right at it....


...I was busy ohming my way around the circuit boards - giving myself a little orientation what track links where, and matching everything up to the circuit diagram.


Here's what happened before that interruption....

I reopened the base, and marked up the big jumble of cables and took plenty of photographs (makes putting back much easier), then gently removed the circuit boards from the base plate:


I took this picture to remind myself which way the microswitch sensors go:


The right-most cable is the Base motor sensor which should equate to MS6, but I need to verify that, so don't take my word for it, just yet!   It's a bit difficult to know what the other sensors are with the arm in total pieces!

Dismantling the circuit boards:




You can see the arm is not only dismembered, but pretty much dissected now !

and Tracing finally begins...

I printed out all relevant data sheets to help because the circuit diagrams are not very clear to read pin numbering.

A couple of minutes in... discovered what that broken track is all about...  it's the +5volt power line!  Still no idea why it's been cut mind you!

Yesterday, I bought track repair paint - I was going to buy a micro-tipped pen to do this repair - but at £40 I thought better of it!  Anyway, now the track has been identified, I will repair this before closing up the base...  hopefully tomorrow evening.

I have now traced half of the data bits through from the initial buffers all the way to the high power motor drives.  This information will make computer programming a doddle as I have removed a good number of unknowns from the equation in doing so.  I'm making detailed notes as I go, and will probably at a later stage draw up new circuit diagrams to be published here.  I also know exactly what line is what on the computer interface port.

Pretty tired now, so I'm buggering off down the pub for a real quick one !!!