Fixing clocks taking names

I was given one of the running club’s older time clocks to take a look at.  I was told that the batteries were dead and the clock was inoperable.  Since I have a history of ripping into electronics I said I would be ok with taking a look at it to see how tough it would be to replace the batteries.

In the past when the batteries died the club would have to ship the clocks out to California to have the batteries replaced. It cost a lot of money to do so. The clocks were so old now that the battery replacement service was not even available any longer.

So I set up the folding table in the garage and plopped the big clock on it.  I grabbed my drill and started removing screws.  I threw the event on Justin.tv and was surprised I had as many as 3 people following the broadcast as it went on.

Getting the clock apart was easy at first and got progressively more challenging as I got deeper into it.  This clock was old, when I got into the guts of it I saw it was manufactured in 1994.  The clock’s numbers are mechanical and are powered by a bunch of large IC’s, and capacitors connected together with tons of wires.

Inside I found two battery sticks, each consisting of eight 1.2v batteries connected in series.  As I pulled the box apart I inadvertently disconnected the batteries from the system board and I wasn’t quite sure where they were connected to.  Once I broke the box down further I was able to split the clock into two sides and got easy access to the board.

Once I saw where the battery connections were I thought I would hook up one of the batteries and turn the unit on just for the hell of it to see what happened.  I was very surprised when the clock reset to zero just like it is supposed to.  What the hell, I thought it was supposed to be dead?

I continued the testing, attaching the keypad and was surprised again when it started keeping time just fine.  Hmmm of course I was cursing myself for not flipping on the clock before dis assembly to verify the problem.  I just assumed it was dead as I was told.

I wanted to make sure that the batteries were indeed in good shape so I found my voltmeter and measured each pack.  Each one read within a few point of 10.3 volts, a very healthy number for a 9.6 volt pack.  Well I wasn’t going to fix what wasn’t broke so I started the reassembly, hoping I could do so without breaking the clock in the process.

Putting everything back together took awhile and involved a lot of trial and error.  I had to make sure I didn’t inadvertently cut one of the hundreds of wires that fill up the interior of the clock.  Eventually I got it all together and once again hit  the switch to make sure all was still working, it was.

I hooked up the clock to it’s charger overnight and checked on it this morning.  It indicated a full charge and worked just fine still.

There is a second club clock that supposedly is also dead. (same model)  I will be seeing if I can bring that one to life.  Of course it goes without saying that this time I will turn it on BEFORE ripping it apart just to make sure.

Tonight I have another home electronics project scheduled, replacing the guts of two Roomba battery packs.  Be sure to tune in.