Retrofitting a 1986 Maho MH400E

Thanks Andy,

The Indramat only has 100µF and 220µF 40V Caps in it.

The biggest ones I have replaced are the 2x 400V 2200µF which are in the Phillips PSU.


I'll ask around my work mates and see if one has an ESR tester.
Mark

I thought it was considered good preventitive maintence to replace thirty year old caps, as they tend to fail rather catastrophically. I know in guitars amps this is commonally done, and also picked up that recommendation for the Indramat, from a retrofitter who had one blow, taking out traces on the PCB.
I have no part numbers for the original caps, but wouldn't any of them also be new old stock, and therefore just as likely to have dried out, and be ready to blow?

I appreciate your input on this.
Mark

The original caps don't have part numbers printed on them. Some have a reference DIN norm.

I went ahead and replaced all the caps. At the same time inspected all the boards for dry joints. The only defects were a couple of spade connectors in the Indramat had pulled their blades out of the circuit board when I disconnected them. I cleaned them up and soldered them back in.

Today I finished reinstalling the Indramat boards, and put power on the machine.

Here is a video of it's behavior...



On power up, the monitor comes up, but only with snow/ rolling diagonal lines. The Phillips 432 controller powers up, but I do not know if it boots up and the monitor is not getting the signal, or it is not booting. Either way the monitor is just showing snow/diaganal rolling.

Hitting the hydraulic start button, I hear relays closing, and the central lubrication system activates normally. Hitting E-Stop shuts down the lube unit. Otherwise it shuts down 16 sec after reaching pressure, as it is supposed to.

The hydraulic pump doesn't start. The backshell on the hydraulic unit 5Y1 switch (manual tool release) was broken, so I have epoxied it up. The wiring did not appear damaged.

I guess I'll have to put 24V on the the Hyd pump relay coil 3K1, to see if the relay is stuck.

Any other trouble shooting suggestions would be greatly appreciated.

Here is the photo of the gearbox shifting unit. Three motors, with feedback through cams and switches.




Since I now have the MESA boards, I am tossing up between continuing to troubleshoot the Phillips 432, or just remove it. If I make a few cables with connectors which interface with existing MAHO connectors, I could do this in a non-destructive manor. The main reason I want to get the Phillips working, is to start the retrofit from a known condition, rather than unknown. Especially if the gearbox timing of the software widget db1981 has written is different from my gearbox, it would be good to have video of the Phillips doing gear changes to fine tune db1981's software to.
Mark

Hello,

optical the gearbox looks 100% identical, I think there will be now differences.

I'm back from tour now, and will get on the Mahos Pc soon.

Thanks a lot for the confirmation.

It is a bit weird that the cam switching blocks have 5 cams and 5 switches, but my schematic (and all other MAHO schematics I have studied) only show 4 switches being used for the feedback.
(Edit] Woops In a different part of the schematic it shows all five with the extra one being "Mitte - Vorabschaltung" Middle permature stop?

Mark

I got some feedback from the CNCecke.de forum that the fluid level in the cerntral lubrication system (currently 1/4 over min) may be low enough to trigger the low level switch. If this is triggered, the system won't latch on. I ordered a canister of way oil to fill that up and see it's effect.

I also ordered an oscilloscope, as I want to scope the graphics cards output to see if the HSync signal is there, as at this stage I have no idea if the controller has booted or not.
Mark

RotarySMP wrote:

I got some feedback from the CNCecke.de forum that the fluid level in the cerntral lubrication system (currently 1/4 over min) may be low enough to trigger the low level switch. If this is triggered, the system won't latch on. I ordered a canister of way oil to fill that up and see it's effect.

I also ordered an oscilloscope, as I want to scope the graphics cards output to see if the HSync signal is there, as at this stage I have no idea if the controller has booted or not.
Mark

Careful in there, there are some treacherous voltages in there.

Check for caps bulging in the vertical/horizontal circuits. Also check for dc voltage being too low can cause this also.I use to work repairing old video arcade games and the crt's always go bad. Most of the time it was caps.

Just my 2 cents....