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Maho mh800 432 will not start - green button does not run reference point

S

scott.bryce

Plastic
Joined
Aug 30, 2014
Location
Australia
Hello all,

I am a brand new member, Located in Australia and I have a MH800C with Philips 432 CNC Controller.

  • MH 800 has been working great 10 years
  • Machine was left to sit for 6 months
  • battery went flat...
  • Lost Constants (Typical)
  • Re Keyed the constants
  • Hydraulics Start Ok
  • Can Jog X, Y and Z
  • CANNOT execute Reference Point Search

I press Enter Three Times, the display shows it is ready to execute the RP Search, but when I press the Green Go Button, Nothing Happens.

I have checked the constants and tool info a dozen times
I have re keyed all the constants 4 times (I was hoping there was one that was corrupt)

I can no longer run the machine at all

  • No system errors
  • No problems/issues in the display
  • The green button simply does not start the machine
  • I can see the green button change from 0-1 in the diagnostics screen, but my machine simply will not start
  • I would really really appreciate some help here


Thanks In Advance

I AM A HUGE BIG DMG/MAHO FAN

Scott Bryce
Proformance Motorsport
Australia
 
Kees said:
Does your machine has a toolchanger? Make sure all sensors are made when the arm is in home-position.
Click to expand...
I asked him the same question in the CNC forum but I wasn't thinking of sensors but rather the fact that you have to have tool pockets listed, which he would have lost when he lost constants...those are not restored with the backup tape and have to be input by hand.
 
One other thing that can change with machine sitting is microscopic corrosion on any IC chips in sockets or relays in sockets. Perhaps try reseating anything that is not soldered in place, including ribbon cables. I've never needed to do this on a Maho but it has worked miracles on many other CNC machines I have owned over the years, so maybe...

Alternative to reseating IC's is application of Stabilant to the IC legs via bottle with needle applicator (quicker and easier that reseating sometimes...depending on how many IC's, how hard they are to get to...that sort of thing)


http://www.amazon.com/Stabilant-5ml...&qid=1409581885&sr=8-1&keywords=stabilant+22a

Regardless of the voodoo surrounding "how" Stabilant works, it definitely for sure works and works amazingly well...saved my rear end many times. If nothing else it helps to quickly show what is NOT wrong with the machine. But often enough it shows what is wrong and fixes the problem. Still best to reseat and use Stabilant if you can identify the particular problematic IC.
 
Last edited:
Is this the machine we are talking about?

980313_698465253534001_2290832140448977816_o.jpg


That is quite an oldie. The fact you can move the axles but not get it homed seems a software issue to me, and not hardware like a bad contact. Maybe indeed an IC has gone corrupt. Have you tried DMG-Mori? They helped me a few times really well on the phone. ( here in the Netherlands) Or otherwise Maho-Docter? I don't know he is still active.

BTW cool stuff you're in...
 
Kees said:
The fact you can move the axles but not get it homed seems a software issue to me, and not hardware like a bad contact.
Click to expand...
I would think so too except he has checked and rechecked constants so many times, which worked for him in the past. I had a 432 Maho once (MH600e) that would not home in one axis. Problem was one of the modules went bad...can't remember which module but it was the one where there are two of the same module...something to do with transferring the info from the glass scales...maybe LM/LM or RM/RM ??

Perhaps he could do a cable connection switcheroo between those two modules to see if anything interesting happens ?
 
Ok - the mystery continues.

I have Two (2) Missing Constants after rebooting and entering all my constants .

Constant 97 and Constant 98 simply no longer appear when I try to enter the constants.

My list of constants that I have used for the past 10 years has 0 in both 97 and 98, but now I cannot enter any data into 97 and 98 because they simply have disappeared...

Any ideas?
 
scott.bryce said:
Ok - the mystery continues.

I have Two (2) Missing Constants after rebooting and entering all my constants .

Constant 97 and Constant 98 simply no longer appear when I try to enter the constants.

My list of constants that I have used for the past 10 years has 0 in both 97 and 98, but now I cannot enter any data into 97 and 98 because they simply have disappeared...

Any ideas?
Click to expand...
Kees, Snee.... what are 97 and 98 for ?
 
Not sure, mine is gone along with all the documentation.

From the image above not sure if the control is a 432-9 or 432-10-- are the constants the same between the two (for a given constant #)?
 
Guys - CORRECTION the machine is a MH900C with 432 Controler (Not 800)

ALSO, noticed after uploading the constants the display is showing INCH, yet the Metric/Inch content is CLEARLY showing the machine is set in METRIC MODE.

It seems that some of the constants are NOT working correctly. The figures are showing as correct, but the machine is NOT reading the constants correctly
 
MC 97 and 98 are not listed in my Millplus, neither in the list of the 500E I still have. It might be possible that MC 97& 98 are enabled by another MC set to "1". Just like when you set the number of axis from 3 to 4, the control adds another 50 MC's for that extra axis.

Silly question: are the 3 little tiltswitches in the controlbox for enable the machineconstants/override/one I forgot in the right position?
 
sneebot said:
The green beast has flown the coop.
Click to expand...
Suspect like me and the Makino you got too high falutin' for such CNC antiques once you got more modern iron, eh ?

Ironic that the one CNC machine that is modern but still has Deckel like capabilities for horizontal spindle and tilting tables...we couldn't buy one even if we were willing to pay the price as they refuse to sell to America ! (Kunzmann)
 
scott.bryce said:
Thanks Kees, yes all the three switches are in the normal position...
Click to expand...
Maybe you said already and I missed it...but how do you input the constants....one at a time by hand, or with the original punched paper tape...or laptop...or ? When you say "re-keyed the constants" do you mean you disconnected/re connected the battery and started all over a few times ? I only mention this as I once typed in constants by hand, had some strange problem and it took me a long time to see which one I screwed up even though I was looking right at it many times before I noticed. I have a tape reader and can feed the constants automatically but a few times did enter them manually.
 
I have typed them in by hand. I have removed the battery and done it three times to be sure. I have had Three separate persons check the constants after I entered them (everyone makes mistakes, adds the extra digit here and there) but no mistakes.

Missing the constants as mentioned above, but everything else is fine
 
Milacron said:
Suspect like me and the Makino you got too high falutin' for such CNC antiques once you got more modern iron, eh ?

Ironic that the one CNC machine that is modern but still has Deckel like capabilities for horizontal spindle and tilting tables...we couldn't buy one even if we were willing to pay the price as they refuse to sell to America ! (Kunzmann)
Click to expand...

Mostly a floorspace issue. The Maho was a great machine-- the Hardinge is just a wee bit faster (understatement)
 
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