1986 QT20n Parity issue

Hello,

Every time I do a search for Mazak Quick Turn information.....google brings me to this forum. I figured I better get registered here so I can get some good answers,too.

I just bought a 1986 QT20n with the T-2 control. The machine had been sitting for a long time un-powered and outdoors......so all 3 batteries were pooped on the FX boards.

I just received the batteries yesterday, and installed them. I followed the instructions to re-initialize the control and reloaded the parameters.

After reloading the parameters, I see a NMI Data Parity error. I then followed the instructions to reset the parity......about 5 times with no result.

On my FX-784-8 card......the center led of the 3 is illuminated.

Does anyone have any suggestions about what this may mean?

I ponied up and ordered all of the manuals last week, but they have not yet arrived.

As a side note......I was not able to make parameter M20 accept any data and clear the asterisks, but I found a post on this forum from someone else that stated their machine was the same way with no effects.

I've done a ton of searching......but can't seem to find the answer I'm looking for.

Just some history......I paid very little for this machine, and pretty much expected the control not to work. I have done a few successful retrofits on some other cnc machines here locally and I figured that I would just do the same to this one......but when the control seemed to initially boot up i got excited.....thinking maybe I could stick with this one. I have heard great things about the Mazatrol conversational control....so if it was cost effective I'd like to make it work.

I'm kind of trying to assess the overall needs of this machine to be able to make a decision about which way to go with it as far as the control is concerned.

I can release the turret, open and close the chuck, turn the coolant pump on and off, and the same for the work lights. I cannot make the spindle respond to any command, move any axis, nor make either the tailstock or its spindle move.

Can I assume this is because of the parity error?

Thanks,

Mike

Yes, parity errors will prevent certain machine functions from working.

Call Mitsubishi Electric Automation (MEAU) in Chicago. They have free tech advice, and can tell you what the lights mean on your boards.

They can also rebuild/repair/reburn any board that may need it. Not cheap though...but hey, who said owning a cnc machine was supposed to be cheap?

Keep us posted...

Catman

michaelthomas said:

After reloading the parameters, I see a NMI Data Parity error. I then followed the instructions to reset the parity......about 5 times with no result.

Click to expand...

Resetting the parity involves flipping a tiny rocker DIP switch (2nd one down out of 8) on FX701 board. If you flipped the toggle switch near the DIP switches, this would not clear the parity alarm.

Thanks for the info, guys

It was the 2nd dip switch that I flipped.

I spent the majority of today.....and yesterday on the phone with Mazak and MEAU. They seem to have concluded that the 784-8 may need repair. I sent them photos of every important screen, and they didn't see anything wrong with the parameters or find any garbage data that would lead to this alarm.

It seems tough to find someone that remembers working on these older machines.....lol.

I think i'm gonna just dive in and put the Dynomotion control in this thing. I already have one setting here, and I actually really enjoyed the last retrofit that I did with it.

I suppose I will have a bunch of Mazak T-2 control stuff for sale if anybody needs anything. The good control cards, servo amps, monitor and such.

I also have a hydraulic steady rest that came off this machine that I'd like to sell, too.

Thanks,

Mike

michaelthomas said:

They seem to have concluded that the 784-8 may need repair.

Click to expand...

Might be as simple as an FX784 from ebay.

If you do part it out, give us a heads up first.

They seem to have concluded that the 784-8 may need repair.

Click to expand...

How much did MEAU quote to repair the FX784-8??

If you could swing the repair, the T-2 controls are pretty darn reliable. I have 4 Mazak cnc lathes with T-2's, and they just run and run when I need them.

Plus, as said many times, Mazatrol programming is the bomb!

FYI, the FX784-8 board has the microchips that contain all the burnt-in Mazatrol software.

Catman

I didn't get a quote on the board yet. I did see some on Ebay....but I wasn't sure if they were going to be direct drop ins or not.

I realized this control has the EIA option.....which I originally assumed it didn't have.

I decided to look things over once more and discovered a bent over pin on the fx784-8 board where it goes into the cabinet socket. I thought for sure that my trouble was over.....but to no avail. I removed the batteries and drained the caps.....re-initialized, reloaded the parameters. Did the no2 DIP switch routine. Same error and same light on.

I then spent the rest of the day figuring out how to power the spindle without the control to see if it was functional. It seems to work normally with a 3v input. The spindle gear box seemed to make a pretty good thump on startup, though. Is that normal?

I can rock the motor back and forth and it has some appreciable backlash in there (gear change box).....I don't know how much it should have, though.

I went into this machine pretty blind......meaning I bought it from someone who acquired it in an auction along with 2 other machines that he wanted. He had no interest in this machine, so he didn't ask any questions about it. It just came with the others. He brought it home with the other two machines and set it outside. The company that owned it before (Crane Cams) has sold out to another company and nobody at the new Crane Cams knows anything about it. It was supposedly still operable at the time of the auction.

I bought it as a project....knowing I could put a different control in it, but really hoping the Mazatrol would work.

The techs seem to be only vaguely sure that its the 784-8 card. My fear is that I will get the card repaired......and then find out that there is a bunch more things wrong with the control.

I really don't know what to do right now.

Mike

that thump might be how your starting it
accel/deccel probly covers that if you get control right
you got alot of t-heads around here
i'd scratch at it a little for you rips its guts out
(somewhat self-serving suggestion )

michaelthomas said:

It seems tough to find someone that remembers working on these older machines.....lol.

Click to expand...

wippin' boy said:

that thump might be how your starting it
accel/deccel probly covers that if you get control right
you got alot of t-heads around here
i'd scratch at it a little for you rips its guts out
(somewhat self-serving suggestion )

Click to expand...

^^^ Resident Mazak Maint Tech. ^^^

He knows a thing or two about older machines too.

Well.....that's really good to know.

I now have an NMI Emergency alarm, too. I cleared this once by unplugging a fan that had quit working and resetting its breaker. I don't see anything obvious this time. I read that there is a way to trace things like this through the ladder. I'm going to dig through the manual and actually try to figure out what a ladder is, how to read it, and where I can locate it......lol.

Any suggestion here would be helpful, I'm sure.

I'm going to look into the cost of the FX784-8 Monday.

Can anyone tell me if a used board from Ebay could be compatible?

Mike

michaelthomas said:

I'm going to look into the cost of the FX784-8 Monday.

Can anyone tell me if a used board from Ebay could be compatible?

Click to expand...

I am certainly no expert, but I believe the EIA software (G-code) is on additional EPROM chips. I was trying to find out how to add EIA to my friend's T-3 as I know it can be retrofitted in the field. I have also found out there is some differences in the control software revision, but we never did finish this pursuit. Not sure it was as simple as swapping out boards or not.

Here are two FX784-8 boards from ebay. One has the additional EPROM chips for optional G-code and the other board does not have them (Mazatrol only).

The last few days have made up my mind on what to do. Today, the monitor quit working. It appears that there is no power to it, although i can't seem to find anything about it in the electrical manual. Its probably there somewhere, but I've been having difficulty navigating it. The manuals are new from Mazak, but they are really poor photocopies with a lot of graining.....especially the electrical manual. Good thing they were only 750.00.....lol.

I'm going to pull the control, servo drives, resolvers, tachos, and inverter next week and get busy putting in the new one......after I do a bunch more cleaning, sanding, and priming. Sometime I have to get back to making a living , too.

I would have loved to give the Mazatrol a go, but I'm just not willing to put any money into it. I have a hard time with things I can't service on my own.

If anyone has need of any of these items......let me know. I plan to sell the working stuff cheap, and the broken parts even cheaper.....lol.

Mike

OK....possible change of plans. (fingers crossed)

Wippin' Boy......I have tried several times to PM you, but it never shows up in my sent mail box. ????? Maybe its sending, but just not letting me know?

I retraced my steps the day the monitor quit working and discovered the trouble. There were 3 fans under the control cards that did not turn. They made a very loud hum when the control was turned on. I removed them. After removing them.....the hum went away, but an hour later the monitor quit working. It turns out that the terminal block that the fans were connected to also supplied the 100v to the monitor. I replaced the screws where the fan terminals were and magically ( Lol ) the monitor resumed functionality. The monitor remained working for the hour after the fan removal because there was likely a very weak contact for a little while. Too funny.

I still cannot figure out the NMI Emergency. I don't understand how to figure out what the possible causes are. Any help there would be greatly appreciated.

Mike

the pms are showing up to me
nmi is wide open for cause.
could be as simple as a break in the e-stop circuit wiring
have you hit the diagnostic soft key to bring up the diagnostic page?
sometimes it will give you a clue.
on an old machine like this rotten little corroded wires can be a real pain.
are there any LEDs lit up on the drives?
hopefully "hit and miss" will see this, he's good trouble shooting these controls as are many others.
I'm just an old goof with a fat black book on these turds, but it does come in handy as these things repeat infinitum

To solve a difficult problem, you must have a copy of the ladder, and know how to "read" it.

Then you can trace what is causing the cnc to throw an alarm, to it's source, by using the bit monitor on the Diagnostics page.

Every element in the ladder has a unique bit. The bit monitor shows you the state of each bit, either "ON" or "OFF". By tracing the alarm's path through the ladder and monitoring the bits, you will pinpoint the reason for the alarm.

and know how to "read" it.

Click to expand...

that's the tricky spot

I have been knee deep in the ladder for a QT-28N with a T-32-2 control that has no alarm, but most machine functions don't work.
I think there may be either a problem with a block of input bits or a open connection (code word for broken wire) for the tailstock switches.
Off to figure out which.....

"To solve a difficult problem, you must have a copy of the ladder, and know how to "read" it."" This is the key.

"that's the tricky spot" X2 Whippin' boy.

Most Mazak ladders do not have a cross reference with them, so I will spend some time noting the element number for the coils of the Y outputs as I am studying it.

Notes in your ladder should always be in pencil, NEVER in pen or sharpie.

The T2 control is well worth taking the time to figure out the root cause of the problem, there are lots of them still in service, it is an early and very solid conversational control.


Bill

Thanks for the further input, guys.

I have the electrical manual.....are the "ladders" referred to as the sequence diagrams in the back, or are they something totally different?

The only response I seem to be able to get from the MEAU guys when asking about the diagnostics page is "You need to send the whole control in for analysis."

According to them, nothing helpful can be ascertained by the customer from the diagnostics page.....lol.

I said, "Well, what is this page for?"

Their response was that it will show you any alarms on the upper left.........no kidding.

I'm not afraid to dig in, but if anyone has some helpful hints on how to read the ladder I'm sure it would go a long way.

I guess the first thing I need to know is do I even have the ladder diagrams.

If its a separate manual from the electrical......then I guess I don't.

Mike

Michael, I saw your reply when my edit completed.

The ladder normally is another manual, but the older controls sometimes had them in the back of the electrical.

I will do a quick look-see of the manuals for the QT-20 in the shop I am headed off to today. With luck I may be able to get the document number.

Bill

I have a x and y element list. This appears to be control inputs (x) and outputs . After that I have about 70 pages of diagrams that I think are the ladders. I'll try to upload a picture of what I have.

Mike