Hello You’all,
Just thought I would post something that may be of help
to someone. I have a 85 vintage Alliant mill with a Sony
LF-200 Magnescale readout on it. The mill has been re-
scraped, new nuts and is in good shape. The readout recently
started to have the jitters. Then it progressed to one axis
counting without stop for a while, then sort of settle down.
Still a bit jittery on the least significant digit. Opened it up
and no smoked stuff. It was getting worse fast. Needed more
warmup time. I new something was about to blow. Looked
on Ebay for another box. No luck. I found a reprint of the
service manual for $80 (Shamrock Machinery), but in my
experience, most manuals say, if this test fails, replace this
board. Since I estimate this unit to be a 1990 model, parts
most likely won’t be found.
With a background such as mine, one has always tried to
fix stuff before replaceing. I built my first tube radio around
1967 and my Dad showed me how to weld around 1968.
The first most likely electronic component to fail in either
tube or transistor/integrated circuit is the electrolytic capacitor,
IMHO. Made a list of all the various values and ordered them.
Meanwhile, back at the ranch, looked on Ebay one more
time. Lo and behold, I found a guy who was offering some
readout board for something and who also offered DRO repair
for something like $100 plus parts and ship. Sent him a email
describing all the measurements I recorded on various test
points on the three boards. (Two axis boards and common PS)
He replied that he would make a list of all those capacitors,
and replace them testing each as you change them. COOL
Got the caps in and replaced the ones on the worst board.
Immediate improvement. Did both other boards and it is rock
steady now.
If someone would want to send the guy I contacted your
readout, he said much thanks for the plug as he needs the work.
His email is [email protected].
This fix will apply to alot of different readouts and all sorts
of older electronics. Once those capacitors die, they usually
short and let the smoke out of something much more expensive.
I hope this will help out at least one person.
Thank You,
Tvan56