QT8 card failures and SQT15M C-axle problems.
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    Default QT8 card failures and SQT15M C-axle problems.

    Ive been reading the forum and looks like there are many who are really deep in to Mazak issues. So, hoping somebody has ideas.

    Bought QT8 from 1994 with T32-2 lathe at this summer. Works fine, except multiple MC712 card failures. The laptop attaches through RS232 to 25pin socket on the side of the machine. From there the cable goes card behind keyboard, from there another cable to MC712. First failure tilted whole machine. New MC712 and everything ok again. Then it lost the data transfer, saying "CMT not connected". Sent both cards to electrics repair and they changed data transfer parts to them and made all internal cables, thought maybe cable failure was reason. The MC712 fix didnt work, and I again changed another used MC712. Data transfer worked one day and the "CMT not connected" error came again. Ran a month without data transfer and finally called to local Mazak service. They didnt know what causes the problem, but we solved it so that changed I65 parameter which changed the RS232 incoming data port from the MC712 to MC116. The RS232 cable was attached straight to the MC116 bottom port. Data transfer worked fine. For a day. After one day the whole machine went off during the thread machining and cannot turn power on again, total failure. Found out the MC116 burned. I have project SQT so I took MC116 from there and the QT8 gets power on again, but cannot run cause parameters came with MC116.
    Question: what burns the card where the data transfer goes to? The RS232 cable and adapter from USB was changed after second MC712 failure. Only thing I havent changed is HP Elitebook I use for the data transfer, but sounds weird that it was the problem??


    Another question. I bought SQT15M year 1992 with T32-3 with C-axle failure. Seller had stripped the C-axle sensors and outer end of spindle. It didnt come with mechanical drawings. Could somebody take some pics of the C-axle sensor section / electric C-axle brake area?

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    Attachment 245059

    Is there a way to check the sensors are ok/broken?

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    Quote Originally Posted by 131rally View Post
    Attachment 245059

    Is there a way to check the sensors are ok/broken?
    you know that output chip in RS232-USB adapters are not fully electrically isolated most of the time. You will be better off if you buy fully isolated adapter. There must be some available for industrial applications.

    like you can have as output this chip

    MAX213 -not isolated if you download datasheet and see how it is built,

    or this,

    MAX250-MAX251 -fully isolated

    Second one is fully isolated and technically, page 8 of its datasheet, there is no way you can burn connected hardware.

    for C axis , it can be second gear with PLG sensor that is connected to MBE90 amplifier and from there goes into spindle controller and NC control C axis input

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    QT8: Ok. So your basicly saying the same as my son is saying = RS232-USB chinese crappy adapter is the reason of the failure? The local Mazak head of service told me that the card can fail even when you take the RS232 off from Mazak when it has power on. He told me change in capacitance can brake the board. Maybe the crappy adapter cuts the line on and off which make some component fail? Anyhow, I ordered "real" RS232 PCI-Express card. Will move from laptop to PC and hopefully that will end the failures.

    SQT15: My sensors have had mechanical contact with the rotating parts, quite deep grooves in them. I noticed old conversation about the C-Axle sensors. A man was going to call to original manufacturer in Japan to find out if the sensor was possible to buy as bulk part from them straight. Pricing was like 300usd. Here official Mazak wants 3000usd for one sensor... Is there any chance the part was possible to buy in some reasonable price?

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    Quote Originally Posted by 131rally View Post
    QT8: Ok. So your basicly saying the same as my son is saying = RS232-USB chinese crappy adapter is the reason of the failure? The local Mazak head of service told me that the card can fail even when you take the RS232 off from Mazak when it has power on. He told me change in capacitance can brake the board. Maybe the crappy adapter cuts the line on and off which make some component fail? Anyhow, I ordered "real" RS232 PCI-Express card. Will move from laptop to PC and hopefully that will end the failures.

    SQT15: My sensors have had mechanical contact with the rotating parts, quite deep grooves in them. I noticed old conversation about the C-Axle sensors. A man was going to call to original manufacturer in Japan to find out if the sensor was possible to buy as bulk part from them straight. Pricing was like 300usd. Here official Mazak wants 3000usd for one sensor... Is there any chance the part was possible to buy in some reasonable price?
    1. there is a difference in between crappy and cheap and fully isolated industrial USB-RS232 converter. WHere there is no direct electrical communication with PC, all is connected through transformer and few opto-couplers. That is what you need, I would guess.

    2. 3000 usd for one PLG sensor is way too much. I guess Mazaky service business isnt doing well in your area, that is why they are trying to catch up with sales spare parts. For 3000 usd you can probably but whole lathe, with dead control but still full of spare parts

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    QT8: I bought "DeLock PCI Express DB9 RS232" for the PC I have near the Mazaks. Hopefully this will solve the data transfer probs. I also bought MC116 and other burned cards from Ebay. Hopefully they will work right.

    SQT15: The machine came to me C-axle sensors and chuck disassembled. We put all together for testing. Mainly all worked, but C cant find home. It gives error 32 with no text telling whats wrong. My errors list dont include 32 at all.. But, I called to local Mazak and they send me service man with oscilloscope to see which sensor or amplifier is broken. Then I dont need to buy more but the broken part.

    Then, I asked from tech supervisor about if I could change parameters so, that I can run the machine with 2-axles, so I can do atleast something. He told it should work 100% fine with 2-axles until I go and try to run C-axle home. But, it didnt. The chuck ran only about 50rpm. The machine has brandnew Freqrol. He guided me through Freqrol setup (with tiny buttons in Freqrol board) and we took off the "back-switching", dont know the term in English. Then the chuck started running normally, and he told the machine has incorrect back-switching. Before this the monitor show RPM only occasionally and max 200rpm was seen. After this it show RPM all the time and tested up to 2000rpm. Though, Im not sure if its showing the actual measured RPM, or the RPM Im asking the spindle to rotate = is it coming from C-axle RPM sensor, or from Freqrol.

    Luckily the technician is coming anyhow next week, so he will adjust that too. If superlucky, it may fix C-axle as well, though its not likely. But, the previous owner had freqrol failure, thats why the machine has brandnew freqrol, and supervisor told the poor back-switching may be the reason for Freqrol failure. We will see what happens when the technician comes.

    Anyhow, the C-axle sensors are very likely broken, they have mechanical damage on top of the sensor. I really need to find proper used sensors, the new sensors are super expensive. So please, let me know if you have some. Also, I need Mazak VDI-40 tool holders + rotating tool holders in reasonable price. Offers are welcome.

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    Your card failures from RS-232 usage are very familiar issues.

    During MicroDisk days (the blue box) a broken ground wire in the power cable would cause massive failures.
    A connection procedure evolved that was connect data cable first, then power cable, then turn MicroDisk on then the power breaker next to the connection port. Power off in the opposite order.

    Then desktop computers came into common usage. Things got so bad at one shop, we had to run a small ground wire first from
    computer frame to CNC chassis before connecting data cable.

    Then laptops came into use. The process was to ALWAYS run on internal battery power only (the power pod was disconnected from the computer)
    while using the RS-232 ports.

    So the basic problem throughout all this ordeal is/was caused by excessive voltage between computer to CNC grounds while connecting/disconnecting the data cable with power on. A bad ground wire or connection at the power plug (often times I would find the ground prong on an extension cord had been cut off to work on a non grounding circuit).
    Most of these devices have power filters inside to filter off transients in the power. If the ground wire is not intact, the ground of the device ( the case or ground pin of the RS-232 connector) will be at a 50% of the power line voltage. This is enough to cause massive problems to both ends of the RS-232 cable meaning computer and CNC if connected with power on. The only USB port I worked with was flakey and I bought them a used laptop with a real com 1 port, it had a grounded power cord that carried through to pin 5 of the com 1 port.

    I suspect that with the new made across the ocean stuff, all kinds of shortcuts have been made.

    So in summary:
    With a good meter (Fluke or similar) measure the AC voltage from pin 7 on the CNC's 25 pin connector to the same pin on your cable, both ends the power is on, more than a volt or two is suspect. Also check reading DC, any spikes as leads are connected is suspect too.
    The other solution is to work with a fixed position computer, AB switches, and the ground integrity is verified for each connection, measuring Ohms on pin 7 to insure the grounds are intact. The AB switch boxes may need to be modified to tie all the ground pind together and not switched. Here the connection is never broken with power on.

    Sorry for the long winded answer, there is over 35 years of experience fixing stuff with RS-232 ports fitted into this answer. My objective in these elaborate answers is to pass my understanding of complex problems down to the newer generations that I will never meet. Hopefully this site will be around long after I am gone. These machines sure will be.

    I still carry a half dozen 1488 & 1489's + sockets in my soldering iron box.

    Bill

    Since this seems to be a new to OP machine located outside the US, please insure that the machine ground lug is connected to your power system ground that is common to all machines and power receptacles, and not just a ground rod at the machine.

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    people make it, isolated USB-RS232

    Isolated USB to USB, RS232, RS485 by EsTools - Engineering Spirit —Kickstarter

    the picture is all you need. Two chips, one transformer and 4 optocouplers. That will give you
    4 TTL-RS-232 lines to use. Need more, same rules apply. No need to go mad with cables and noises, ,oscilloscopes at all,
    Just open your converter and take signals from it and use your own external drivers. All components will
    cost you few dollars. No need to make PCB board at all. How much did you already spend on your MC116 boards?
    MAXIM is a company that is dedicated to interfaces and all sort of issues with them. No need to make life even more complicated then it is.

    untitled.jpg

    untitled.jpg

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    QT8: Looks like I finally get the used board from Canada this week and can start testin. "noname777", to make this clear, I will just go and order this:
    "Pledge €55 or more
    Fast decision.
    1 IsolatedSerial board, assembled and tested. Documentation as download"
    Then just put laptop USB to the board, from board RS232 to QT8 and I should be safe? "Hitanmiss" are you thinking the same?

    SQT15: the service man should have visited last week, didnt due long repair elsewhere, hopefully will come next week.

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    What i am trying to say is: Any USB-RS232 converter that says " electrically isolated" will help you a lot. You either make it, what I would do if I was you, or get it ordered from internet. But, to be honest, I couldn't find any finished and more less trusted product on-line to recommend you, just the link above.

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    QT8: OK.

    SQT15: The service man visited. Im having absolutelly destroyed sensor in C-axle MES00011390 - BKO-NC6572H21 but looks like the amplifier is ok. The RPM sensor is propably also broken, but its almost working. Giving weird waves to oscilloscope, so looks that I have to find that too. But that amplifier is also working. RPM Sensor MES00011380 - BKO-NC6572H12 . I really need to find them elsewhere than local Mazak. They ask so mindblowing amounts of money, its not option. Could somebody help me out?

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    Mazak monopoly, unless you replace whole system ( PLG+ Amp) with something like alternative staff... HEIDENHAIN and the ones that will be suitable to go along with Mitsubishi data protocol. Which is possible, in your case.

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    Quote Originally Posted by noname777 View Post
    Mazak monopoly, unless you replace whole system ( PLG+ Amp) with something like alternative staff... HEIDENHAIN and the ones that will be suitable to go along with Mitsubishi data protocol. Which is possible, in your case.
    Could you explain more? You mean I could use Mazak trigger gear and just change the sensor and amplifier? What would those cost like?

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    Quote Originally Posted by 131rally View Post
    Could you explain more? You mean I could use Mazak trigger gear and just change the sensor and amplifier? What would those cost like?
    that is just an idea, I know for sure, that HEIDENHAIN makes some encoders with Mitsubishi interface. I bet your choice would be to find some companies that retrofits old CNC, make them new , with old hardware but new servos and amplifiers. They probably know how to deal with this Mazak drama.

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    Not sure if you've found a solution for this already, but another option for RS232 electrical isolation are in-line optoisolators. With these you would not have to use a whole new USB-RS232 interface. Something like this, not endorsing this particular brand but it's first result with a quick google search.

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    Does somebody know if CM16AC is a fit to SQT15? These are commonly for sale as used for 500usd or so. Like this:
    TAMAGAWA AU591 65991492 ENCODER KIT , SENSOR CM16AC5386. | eBay

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    Quote Originally Posted by 131rally View Post
    Does somebody know if CM16AC is a fit to SQT15? These are commonly for sale as used for 500usd or so. Like this:
    TAMAGAWA AU591 65991492 ENCODER KIT , SENSOR CM16AC5386. | eBay
    this one is old school, only for old Mazaks with spindle control RPM and orientation (option), A,B phases and Z pulse per revolution for orientation.

    the other thing is. Why your PLG head failed? Possible that spindle rear bearings run out is so huge that it could not maintain proper gap in between gear and PLG head. You spend half of a million on new PLG head and then gear will eat it in a month or two. What if spindle bearings are bad and worn out?

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    I have been using this with no issues on my QT-15

    https://www.amazon.com/dp/B000067RWK...748420_TE_item

    just needed to make a crossover adapter to correct the pin-out

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    I found H21 sensor. But H12 looks to be quite difficult to find. But, I found several of BKO-NC6572H11 and in coding only difference is the last number. Mine is BKO-NC6572H12. Any knowledge of from which machine this is from? And if they are interchangeable?

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    what type your amplifier? MBE90K? send me your email into private message, i will send you a file


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