[Sotris]

Hi

we have here a FANUC 0-MD unit with a A06B-679305 3axis servo amplifier.
During power up the machine produce an error on screen "424 Servo Alarm Y Axis detect err" . At the same time on the 7sg LED of the servo amplifier show 9. (9 with dot).
We have disconnected the Y axis motor cables from the amplifier and the error remains. We have also interchange the X/Y axis motors and error codes remain unchanged - 424 & 9. - even doing so!
According to manual, these errors if they persist under all those test, shows an IPM IGBT module failure. Our amplifier uses FUJITSU 6MBP20JB060-03 IPM for both the Y & X axis. We order a pair of them & we received them already. Before we replace it, I would first like to know if there Is a critical difference between the 6MBP20JB060-03 and the same but WITHOUT the -03 suffix at the end of part Nr, as the received new ones are not including the -03 suffix (although we order the correct )! Are those direct replacement, or not?
Second, is there something else we should check before replacing the IPM;s. Should we check also some other parts, ie. the IPM driver optos and their peripheral components?
Any other suggestion to check out, while we are at the IPM replacement process, and there are part beneath them that if someone needs to replace them also will have to pull out the IPM again?
Any other general suggestions either o repair - possible related faults - or for testing before installation?

Thank you in advance

Sotiris

[guhl]

check DC voltage at your IGBT module. this is one reason when module generates alarm

[Sotris]

Hi
Thanks for the reply.
Which DC voltages your are referring to? The HV DC as I see it goes simultaneously to both X & Y IPM modules and probably also to the Z axis one. So, I guess if there was a problem with it there will be two errors show at screen, ie, 414 & 424 at least. Or my assumption may be wrong for some reason? However I have checked the DC at the power supply bars before removing the servo amplifier, and was 308V if I remember it correctly.
Or you are referred to the DC voltages for the opto drivers of the IPM? Are those coming from the IPM itself or they are created by an external subcircuit located at the same PCB? According to the 6MBP20JB060 datasheet they seem to come from the IPM itself, so I guess an erroneous voltage on them leads also to the changing of the IPM. Is that correct? I'll make a search on the board to reverse engineer the related circuit paths.
The IPM power board is A16B-2202-784
and there is also the digital logic I/O add-on board on top of it (A20B-2001-0940)

Somewhere I have read that changing faulty IPM IGBT's should be followed by changing also the drivers (meaning the driving optocouplers I guess) of them in most cases. Is that true? As I'm not sure if that should be taken in account, since an ohm meter testing I did didn't show any leakage or short on them, both at the input & output leads.
The truth is that a schematic would much of help, but I guess that is more or less like searching for gold in sahara!



So, any help would be much appreciated!

[guhl]

I meant DC voltage, which comes to IGBT module. If DC voltage ok, check transistors
there are three causes of alarm inside IGBT module, one of them is undervoltage.

[lixinweabc]

Dear all:

The FANUC 0-MD system on my CNC machine tool also has such a fault alarm. Please give me some advice on how to diagnose and maintain it. Thank you!

[lixinweabc]

Dear all:

The FANUC 0-MD system on my CNC machine tool also has such a fault alarm. Please give me some advice on how to diagnose and maintain it. Thank you!



The driver shows alarm No. 9, the system screen shows 424, the fourth numeric digit in line 721 of diagnosis 1. By querying manual #4 HCA abnormal current alarm.