Retrofitting a 1986 Maho MH400E

There are some useful photos of a Heidenhan LS403 scale read head just entered by "/Kammlake" at Pract Mach website-"fix your MAHO" section..
Mark , if you can figure out how to drag your neat information on cleaning the scale and the PDF over there (I gave up trying ) - it might help to get another MAHO up and going.
Think Spring and warm basements

Got a little more done yesterday. Just scratched my head wondering where I left off, then rivetted the button mount screw plates onto the face plate, and mounted the USB extensions.


Mark

Glad to see you are making more progress.
Was comparing the front panel photo of Jan 3 to this photo and wondering if the front to back have been switched. Or is this photo showing a before the riveting is done layout?
Hope to include a PDF showing some miniature 5 volt light bulbs that might be useful to repair a LS 403 scale. Seems interesting the range of expected life span for the bulbs.
Would be useful to know what the LS 403 photo sensors spectrum sensitivity is, especially if trying to convert from incandescent to LED .
Any way glad to see you are making headway !
confused Bob

Hi Bob,

The photo above is the back side of the front plate. I didn't want a bunch of extra threaded fasteners through it to mount the button carriers, so I had plates lasered which got riveted. I'll update the photo to make it clearer.



My LS403's require both 5V and 12V DC supplies. Not sure which supply is for the bulb, and which powers the sensing head. Thanks for the file on the bulbs.
Mark

Was hoping to see/hear more results of the retrofit.. Has warm weather been postponed in your area too ?
Poked around a Heidenhain Exe board with a Ohm meter from 12 volt Bd. test point to the scale input connector. Did not find conduction to any of the scale input board pins for 12 volt. Did see zero ohm from 5 volt Bd. test point to scale input connector.
Do remember using a infra-red TV remote pointed at a scales sensors to get it's readout to indicate some action.
Anyway, from the cheering section --- Go Little MAHO Go

Hi Bob,

Thanks for the information on the EXE board. That is very helpful for when I finally dig into that vertical LS-403.

Spring is busier than I remember. Garden grows like crazy, we seem to have a wedding or party event every weekend, and I am struggling with the course I decided to do this semester. I am pretty good a procrastinating, but don't give up projects, they just have pauses in them. Thanks for the motivational reminder.
Mark.