Tuesday, April 23, 2013

AX relay success!

ZOMG YAY!   I finally fixed the AX Relay!  Now, while this is awesome, that just puts us back to "motor spins endlessly" and the reset never completing.  But oh I was so happy to hear that motor start spinning again, knowing I had been able to undo the damage I had previously wrought.
I am away for a bit, but when I get back I will start investigating the startup issue anew, focusing on everything else that is NOT that AX/BX relays, and see where I get.

But on to the AX Relay.  Take notes, you will need this info.
So the first thing that goes  through my mind is to look for things in their powered-off state.  The switch is not activated while the score motor was running endlessly, and so the error should be in how the switch sits in it's non-activated state.  There could be issues with the settings while "activated", but that's not effecting us at this point since we never get to that part of the cycle.

A bit of terminology:  
Apparently switches that are open while the relay is off are called NO, for Normally Open.  If the switch is closed while the relay is off, that's NC, Normally Closed.

what, you gotta problem with lil ol' me???
Take a look at the right-most switch.  It is a NC, normally closed switch.  Looks pretty darn good, making some fine contact.  As it turns out, it was the culprit.

On some random pinball forum I remember someone mentioning using a wooden chopstick to troubleshoot the relays.  I had forgotten about this, since I now have a switch-adjustment tool.  Why would I use anything so clumsy to bend the blades?
What they didn't say is that the wooden chopstick is for when the machine is ON.  While powered up, delicately make sure the NO switches are truly open, and the NC switches are truly closed.   Trusty chopstick in hand, I made the tiniest of pokes to that right switch and CHA-CHUNK the motor begin endlessly spinning once more!

Now that I had found the culprit, I had to put together a fix.  I latched the switch, thus opening that NC switch.  This gives ample space to bend the stationary blade towards the receiving blade, making sure that the resulting open gap is respected.
Always good to remember:  Always tighten switch stacks FIRST, the screw closest to the blades first, and then the 2nd one.
Thinking that there might be residue blocking a solid connection (because hey, they are TOUCHING, but perhaps not touching well enough...) I got out some 400-grit sandpaper, cut a tiny bit, folded it over, and rubbed it between the contacts while the switch was open.
I had bought some Flexstone files, as they seem to be the most recommended things for cleaning contacts, but for AX/BX relays I argue that they are way too thick for the delicate touch that is required.

Pinball Wizardry, here I come!

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