[Emc-users] DRO failureType FAGOR 0-300 (spanish made)

[Peter B. <p.b...@dr...>]

Gentlemen,

a little off topic, sorry: A 3 axis system of above type was given to me 
because of beginning irregularities. As it turned out, all three axis 
displays are working, but mostly show irreproducible numbers, i.e., when 
pushing a glass rule slider forward and back again to the same position, 
the display does by far not return to the start value or what's worse, 
the direction of movement is not even always detected correctly. The 
sensors were well covered with grease and sticky. I cleaned all three 
carefully with alcohol but it made no difference exept that I get no 
greasy fingers any more.  The electronics unit seems to be ok, too, 
probably no noise affair or so. All three channels going crazy in the 
same manner point to a common source.

The device itself is probably rather ancient, but the manual from FAGOR 
is still available on the internet though apparently for newer models.

It looks like the glass measures are functioning just like rotary 
encoders with ground and +5V, A, B and I channels. The index home 
position is indicated on the outside by a mark.

My suspicion is that the infrared LED's in the sensors have lost power 
so the electronic counters don't get all the pulses from the sensors 
anymore. I know this decaying phenomenon from other long term 
performance or high power LED applications such as CD burners and 
refrigerator indicators. And as I know how workshops run, machine 
readouts are never turned off because they usually don't have a separate 
switch or the workers care the heck, so anyway, they get a lot of hours. 
Replacing the infrared LED's would be tricky, but relatively easy if it 
were worth wile.

Can you imagine that my suspicion is right? Does anyone of you have 
experienced a DRO behaving crazy in this manner without a recognizeable 
reason, and has anyone repaired one (successfully ;-)?

Thanks in advance from

Peter Blodow
Ehrenberg, Bavaria