Problem with old GE 7542 control.

[NcDave]

Hello,

I have a old General Electric 7542 control connected to a Warner
and Swasey 1-SC lathe that I use mainly for one project part, this old
control has worked fine till reciently, the problem is in the offests, it
has thumwheel offsets that has a "X" axis problem, whenever any offset
is called up the X amount moved is correct. BUT the direction is wrong.
SO x-.020 will move in .020 but when the offset is cleared it still moves in
.020 instead of moving back to where it belongs, even if a x+.020 is
entered in the offset it still moves x- and clears x- therefor the distance
is correct but not the direction in the X axis.... BUt the Z axis offsets works
fine BUT and any axis movement in MDI wont work... I cleaned and reseated
all the logic boards and checked all fuzes,, i feel its a bad board in the logic
stack but I dont know which one... is anyone any idea how i can fix this
problem... I have books and diagrams on the control but my Knowledge
of electronics is not in depth.... Any help is greatly Appreciated..

Dave.

[FMCoUSA]

Have you had any luck with the offset problem. Try the CAP2 board its one of the 1/2 height boards, when I had that problem it effected both axis the same way. middle row of cards, 9 from the right. Good luck, Mike

[FMCoUSA]

is this a 7542 control

[John Michael]

The CAP-2 board calculates the incremental move when programming in absolute G90 mode. It usually calculates the wrong size move when it failes. Tool offsets involve the TO-1, SD121 boards and some IF241 boards. Do all 4, 8, 12 or 16 tool offsets do the same thing? If it is only four bad offsets it may be the SD121 board associated with those four. If all offsets are bad it could be the IF241 board in slot 1-14 although it seems that the IF board in that slot would also make the Z offsets bad. The TO-1 board is the tool offset board, it is always suspect with an offset problem. IF241 boards are all alike, you can trade one with another but know where you put it because something else won't work after a trade. You can also trade SD121 boards but there is only one TO-1. And you might just fix it by unplugging, wiping the contacts and replugging the above boards. These controls are known for connection problems.
John

[John Michael]

Well, after all of that explanation I just noticed the original post was 6 months old. It is surely fixed by now. What was it?
John