Thread: QT-15, MR-S1 Servo Fireworks

Well, not a good day today,
Went to the shop to try a new tool, power machine on, control on, and ... Bang, sounded like a firecracker coming from the back cabinet...
Looked at the monitor, and Yes there is a servo drive alarm plus the emergency alarm. Shut main power Off right away, and as I opened the cabinet i could see the smoke coming out of the drive.
The drive is a MR-S1-80, and I can see a smoked spot were three diode are ( Between the two left edge connectors), the contactor is also stuck closed and the three phase bridge is shorted..
I know some of You have gone thru this already, tough repair ? any recommendations beside calling Mitsubishi, ? (I will do in the morning )
Or maybe someone has a spare taking up space that wants to sell ?

Thank You in advance
A.M.

amp repair is simple
pull it and send to mits
don't figure thats what you wanted to here
sorry
fastest turn around i ever got was when i put a hand written note on drive saying
"refill with smoke and return please"

With the drive contactor welded together the first thing I would check is the three phase wires out to the motor to ground. If nothing there I would check that he three leg wires are isolated and not shorted together. Thirdly megger check the motor. Sounds like something external took out the drive to weld the contacts together. A new drive installed may pop as soon as you install and power it on without being sure of the externals! Good luck stuffing all the smoke back in that little hole!

well...
Here are the latest news.
The day after my first post the drive went out to Mitsubishi.
Called Mits. this Friday, and they say the drive cannot be repaired " Because there is something shorted" ... really ?.... why do you think i sent it to You?...to get deodorized ?
Moral of the story the guy at the phone give me 3 choices

1. Buy a refurb Unit for $2150
2. Buy a refurb. current replacement for that drive $3400
3. Buy a new current replacement $5300 +

I had the impression that possibly the want to phase out the MR-S1 drives repairs for the newer substitute
Of course no core credit from my unit, so i got the first choice and my old POS back, paid close to $2400 and... was not enough. The kid called back 30 min. later saying that if I wanted the drive i had to fax him a signed document ( That he was going to fax me first ) stating that i was not going to re-sell the drive to Iran, iraq, S.korea and a bunch of other third world countries..guess they have to do that .
Done that, the drives should be back at the shop early this week.
Leelund, I have checked the motor connections right away because I was thinking along those lines, but did not see anything suspicious, not a hint of high resitance toward ground, nor a shorted coil ~2- 2.5 ohms sanme reading on all three, but tomorrow I will put a megger to it, just to be sure, thank You for the heads-Up.
Wippin Boy, They are probably glad to talk to You and fix Your stuff in a hurry, seen the amount of $$$$ You mus have sent to them during the years,... but Me? too small of a fish. No smoke refill for me.
One thing that I would like to try is on spare time, refurb the " shorted " drive, definately I have nothing to loose, and will be a good learning curve.
I Know, few of You out there, have "been there done that". Please let me know the difficulties in finding parts like the thyristor pack and / or other proprietary components. I will really appreciate all the input.
can post pics if needed

Thank You all in advance
A.M.

Hello!

I have had pretty good luck with Mitsubisi, it is always a little stressful. The machine is down, you are loosing money every minute. We do not make a lot of money but I try not to buy the refurbised stuff, the fresh stuff is worth the money, even from Mits.


Stuff breaks, you get hot but it sounds like it is time to move on and make money. There are a lot of people selling refurbished online, they might even buy your core, but again, this stuff is getting old, they do not advertize it but you run heat and electricty through something cycled a few million times,
good luck!
Yea, "been there and done that"!

Good luck!

LandM-1

Yes, I generally think along the same lines, but the refurb unit was the only one available for the original drive, and it has a 1 year warranty. I can bolt it in as received and it will be good to go. Figuring that the old one had been there close to 20 Years, the refurb replacement will be fine for the foreseeable future. Also my machine i can assure you is not at all busy at the moment.( Unfortunately)
By reading the comments on this board, I also realized that Mitsubishi is probably among the best when it come to service, and prices of their services. The original repair quote for the servo was $1150. Considering overhead, parts, and labor, It takes time to receive, disassemble, troubleshoot, repair, test, package/ship, the 30 lbs drive... their margins are not that high.
Still I would like to fix the old Unit. If possible

Considering there are thousands of Mazak machines (most of the T2/M2, and all of the T32/M32 controlled ones) out there using the Mitsubishi MR-S series drives, Mits needs to make a more legit attempt to rebuild these drives.

"Something shorted" sounds like a corporate initiative to sell new drives, rather than fix existing.

BTW Andrew, did you get part numbers for the current replacement drives? If not, give 'em a call and demand it, and we can watch Ebay....

Greg,
That is the feeling I had too, but an attempt was made to repair it, I found few parts replaced already until apparently they got to a dead stop, possibly from a lack of components. I wish I could get a diagram for the drive .
I did ask for the replacement drive, and it is the MR-S11-****.

Hope it helps, got to go.

Thank You
A.M.

I did ask for the replacement drive, and it is the MR-S11-****.

Ahhh. I have seen the MR-S11- drives, versus the MR-S1-. So, the 2nd "1" means it's a slightly newer, updated drive.

My QT15's have MR-S2- drives, which are 2-axis-in-one-drive types. Thus, I need to be on the lookout for a MR-S21-.....

Hey Andrew, I have tinkered with these drives quite a bit. AFIK, the only proprietary components are the "hybrid ic drivers", which are chips made by Mits that control the large base transistor(s). These hybrids stand up, have multiple pins inserted in the board, and look as if they are dipped in epoxy. They will have a number like: DK434, or DK456, ....

Everything else on the drive (except maybe the main processor chip) is available from other sources.

Maybe post some pics of your drive board and the suspicious components?

Thanks,

Greg

if it makes you feel any better
we have all got the "obsolete" story at some point.
there are just too many flavors of drives out there to keep them all running forever.
for awhile I couldn't get a decent fix on a FR-SE drive, just not enough good IO1 boards made in the original production runs to keep up with how fast guys were smoking them off. drives would come back with boards looking like a lace doily on the back from all the short repairs done to it (my guess on your drives problem) these things have multi layer boards and when you start really melting them down its just not practical to repair them any more.
i know its a tough deal but chances of fixing it if mits says its junk are probly slim unless your a top level EE with experience at this kind of stuff
might be worth a look at the scrappers market for a pulled unit but then its a gamble,
you may have to just bite the bullet and pay the man (mits) being your safest bet
sorry
i wonder how little guys keep these cnc's running
they can be real money pits

CNCTOOLCAT,

The drive you want to keep an eye out for is actually an MR-S12 drive, not 21.

Whippin boy is right about the multi-layered boards. Once you have a hole or pad lifted , you are gambling with fixing it. The boards have ground planes which can short all kinds of stuff together.

CNCtool cat mentioned the hybrid components which is part of the firing circuitry for the base transistor. If one of those are bad, then chances are you will also take out a base transistor or IGBT. This is an area where most mistakes are made. If a new base transistor is installed without fixing the firing circuitry, then you will most likely see more fireworks.

Regards,

Chippy

I know this is an old thread, but did anyone ever find a place to repair Mitsi drives? (besides Mits)

Also, does anyone know WHAT the drive designations actually mean?

What do the third and fourth sections of the model name mean?
MR-S12-33A-E01 for example. What does the 33A and E01 stand for?
Can one substitute a 80B or 100A for a 33A? What fits what?

Thanks.

there are other companies out there
i used one once
took twice as long, cost the same, and came back with a mits bar code lable on it
hope you have better luck