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Bought MAHO MH600C, looking for some tips


Dec 19, 2021

This is my first post on this forums.

I recently bought old MAHO MH600C cnc mill in pretty good mechanical condition given its age (1984 vintage according to manual and name plates) . Machine has philips 432/9 control with crt monochromatic screen.

I got it set up and running with few hiccups (Z axis started homing in wrong direction for some odd reason, tripped estop and I had to manually turn the belt to get it off the limit switch. Now I always leave all axes few centimeters from home positions when switching off the machine and it works good).

I got RS232 working (no dnc sadly, my software is too old for this), I dumped constants to a file and backed it up.

I have all the manuals and electronic schematics that came with the mill (in German unfortunately).

I've read through quite a bit of threads on this forum and others and compiled list of stuff I should do to keep my new ancient cnc in good working condition. I would be grateful if you could go through my list and add thing or two if I inevitably missed something.

1. Preventative maintenance. I plan to replace electrolytic capacitors in servo drives and PSU in near future, before they fail (if they fail it will be hard to repair). Anyone has a list of them, or do I have to look up values from the pcb?
I looked at carbon brushes in the motors and they are within the spec (longer than minimum recommend 10mm). How long should be new brushes (I plan to get few spares just in case)? Checked oil levels - all good. Checked belts, slop in the ram and table, I did not notice anything abnormal. Should I check anything else?

2. Dealing with existing faults. Machine sometimes shows error 16 (Y axis slip clutch) on the led display during fast moves G0. Control throws no errors. From discussion on the linuxcnc forum I know that this is probably due to Y axis clutch slipping during high acceleration moves, and clutch needs to be cleaned and recalibrate (thanks ihavenofish!). I know where it is (on the bottom of Y axis ball screw) any tips how to get access to it without lifting the machine?
Sometimes I get X01 error (linear scale pre-alarm), this may be due to dirty X scale - is there a way to clean it without pulling scale from mill, disassembling it, cleaning and resealing with fresh silicone then remounting it on the mill? (i found guide how to do this on heidenhein scales here on the forum, it should be similar enough for philips scales). It seems awfully dangerous and unnecessary to dismantle working component that is almost impossible to replace if damaged during the process.

3. Coolant. I plan to use cimstar cimcool 4800ff coolant on the machine, do you have any recommendations against it? I have heard of problems with swelling trucite from wrong collant on this machines. Has anyone been using it on maho?

5. Oil. Any recommended replacements for Cl46 oil? I can't find the stuff in Europe, other recommended oil type (cglp68) is readily available, but Cl46 is not (at least in quantities less than 200l drum). I found something designated as L-AN 46 but I'm not sure if it is right type of oil.