[Motufaga]

Hi,

I have been trying to repair this machine (CNC lathe LB9 OSP500L-G)and hope someone can help me with these:

1) There is no display on the monitor when the machine's main breaker is
switched ON
The Control ON/Reset switch when pressed lights up with the NC status lamps and then all trips OFF. On tripping OFF, the OPUS 500 unit(CPU rack) shows 3 lamps on ON state; i) under voltage ii) +24V iii)+12V

If CPU power supply module is removed from its "connector slot" and the main breaker switched ON, the Control ON/Reset switch lamp lights up when pressed.No alarm lamps light up on the CPU rack but +5VDC,+12VDC and +24VDC are measured on the power supply unit with the multimeter.


2) None of LED's on the VAC III spindle drive unit are ON.
The voltages measured between the inputs of 3P lines to the spindle drive unit are 200V AC.The labeling on the 3 phase lines are: R2B,S2B and T2B.
The output lines to VAC motor (labelled U1,V1 and W1) measured zero between phases and 3.5V AC when measured to ground.

On the spindle drive Control PCB, CN7 connector pins 1 and 3 measured 7.5V AC and connector pins 2 and 3 measured zero volts .As the measured voltages are not 19V AC the manual states to replace power supply unit.
I have not found this power supply unit yet so I have decided to post this thread for feedback. Im a fitter machinist with CNC programing and machining experience and studying mechatronics.
Please any help on troubleshooting the above mentioned problems will be greatly appreciated. Thank you

[fordav11]

the 'under voltage' lamp suggests a power supply problem as you have found when you measured it and got 7.5V where there should be 19V.
so you need to find the power supply that is the source of the 19V and check it / repair it / replace it.
Power supplies are pretty easy to repair with some basic electronics knowledge and a little experience.
It'll be expensive to buy a new one (if you can find one) but you should try getting it repaired at a TV repair shop or a similar place.

[Motufaga]

Thank you fordav11.
After removing power supply board (VAC III unit with 50 screws on it) I found the transformer, magnetic contactor ,huge capacitor,transistors etc. behind the board.I discovered that almost all the screws represent test points on the power board so I fitted them back,switched on the main breaker and tested the board.
The inputs to the transformer were the same as the outputs (200V AC between the 3 phases or 115V between a line and ground).

The outputs from the transformer are connected to the magnetic contactor. There are no output voltages from the contactor and the two points for relay circuits of the contactor also measured 115V AC to ground.

Please if some one can help me with the what the output voltage from transformer be for this VAC III spindle drive unit?

[Motufaga]

Ive found that the transformer I mentioned in my last thread is not a transformer but a choke coil.:withstupi

My eagerness to learn this electrical/electronics troubleshooting is making me feel stupid. My apologies. (chair)

I would like to say thanks to diegojulio for the VAC III maintenance manual
Im going through it and looking at my last thread the voltage measured between the two contact points of the relay for magnetic contactor was zero
any one of these points to ground =115V AC
The circuit for the relay for the magnetic contactor switch seems to be the problem

Ill post again when sort fix this problem
(wedge)

[Algirdas]

1. Do You have electric diagram of the machine?
2. Did You checked the +24V and, if it is there -24V ?
3. Are You trying to fix spindle drive unit? It looks, the control doesn't powers up, so Spindle drive is not the first to fix ...

[Motufaga]

Thanks Algirdas, with my little knowledge on electrical/electronics please guide me.

1. Do You have electric diagram of the machine?
No I do not have.

2. Did You checked the +24V and, if it is there -24V ?
Please help me on this one?

Ive checked -24VDC on a power supply - maybe for servo board???
Also measured +24V DC on (CPU power supply-rack insert type)

If +-24V is not from above but from VAC III spindle drive unit then please help me locate it?

3. Are You trying to fix spindle drive unit? It looks, the control doesn't powers up, so Spindle drive is not the first to fix ...


yes i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output.

Please point me in the right direction if not spindle drive?

Ive just measured CN8 (is it connector 8 ?) between pins 3 and 4 and its about 287V DC . VAC III manual says if not 300V DC then no power is going to Control PCB.:stickpoke

[Algirdas]

Let's start from the beginning:
1. no electric diagram.
no comment. nothing to comment. I would strive to get the one whatever costs. Okuma dealer must be able to provide, I believe.
2. +24V and -24V must be present on power supply block. It's in the CPU rack, most likely.
if You have +24V on Emergency stop terminals, it means, that control is powered up. If You have ±24V somewhere else, it means, control is ready to be powered up. Roughly saying ...
if control is powered up, You must see indication on OP. All indicators are on for a while on POST, to be sure they work.
3. i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output
please explain. what is not relaying from input to output?
4. Is there a reason to dig inside the drive unit?
can You switch on: - the machine; - the OSP?

[Motufaga]

3. i was looking to remove magnetic contactor switch to find out why its not relaying from the input to its output
please explain. what is not relaying from input to output?

Ok I was sick and now im back. ive drawn a diagram attached
There are voltages from the SDU input terminal to the magnetic (switch), but there are no output voltages from the magnetic switch to the three transistors.

4. Is there a reason to dig inside the drive unit?
can You switch on: - the machine; - the OSP?

Yes can switch On but the machine is not booting up nor display from monitor.
I was looking for the SDU power supply(stepdown,rectifier)...?? not sure...that is if DC voltage not from CPU or other power supplies.

1. no electric diagram.
no comment. nothing to comment. I would strive to get the one whatever costs. Okuma dealer must be able to provide, I believe.

Ive emailed Okuma dealer after I read your comment and with all that ive read about Okuma, wasnt raising my hopes but i received the wiring diagram today,great.Thanks, Im trying to understand the Japanese/English on it ha ha .....ill post the above anyway....

[Algirdas]

but there are no output voltages from the magnetic switch to the three transistors
Did You applied control voltage on contactor coil? No. Right, don't do that. Contactor is not on until is not commanded to. That's right
but the machine is not booting up nor display from monitor
this is a start position to diagnose: power supply first[/COLOR]
i received the wiring diagram today,great
Lucky You. Now You can handle where control voltage is missing and why.

[Motufaga]

Please help
Attached is the control Power Supply diagram.Ladder diagram?

Cant figure out the control voltage between +AL and -AL.?
zero voltage was measured between +-AL.
Is there a problem with this power supply?

[Algirdas]

the diagram looks familiar :-) what it means:
if voltage between AC1 and AC2 is about ~200V
and
there is no short circuit on +V -V terminals
and
P.S.C. unit is healthy
and
Control line "54N" is alive (+24V, I guess)
then
CB2 (Control Button #2 ?) is ready to switch on EC control voltage.
~~~~~~~~~
if line "56N" is alive (+24V, I guess)
EC control voltage can be switched on
~~~~~~~~~
+AL_-AL can be spikes (pulse). Measuring as constant voltage maybe wrong. check it

[Motufaga]

Thanks again Algirdas

After some testing there is DC 24V across 54N and 56N and also across +V and -V so there's no problem with the control power supply.(flame2)

Testing the CPU power supply there are DC +5V, +12V, +24V, ISO+24V on its test terminals when powered ON and not connected to CPU rack

When connected to CPU rack and powered ON, none of voltages appeared(measured) on test terminals. Power supply alarm indicating lamps on CPU rack light up for under voltage, +24V and +12V.

From the manual these alarms indicate abnormality in the power supply or in input or output parts.

Please help me from here
From the above tests there don't seem to be a problem with power supply?

assuming the problem to be output from power supply to bubble memory(bubble memory require DC +24V and where loading is done) I cant tell if my system is loading or not because there is no display on control panel
How can I test the bubble card or CRP Board -II D which interfaces Control panel?
Or am I missing something ???????

another glitch!!;
Is it ladder diagram on control power supply diagram attached last thread?

Ive done PLC programing and interfacing but I still cant find what some of the symbols represent on the wiring diagrams?
i) two arrow heads ( PS diagram)
ii) line with circle and labelled pt (PS diagram)
iii) switch (normally open contact) with a number written to the left and right of it. what the numbers indicate?
iv) capacitor symbol or something else?( across +AL and -AL ---PS diagram)

Any help, contribution on the above will be greatly appreciated.
Thank you

[Algirdas]

just a seccond. step by step.
You see, the 24V is shortened somewhere after power supply unit.
disconnect the load branches one-be-one till power goes on back.

[Motufaga]

Wow! Many thanks to you Algirdas

I caught the barga. oh maybe?

Disconnecting the bubble card, caused the appearance of this display on control panel of monitor:
SBP4 - E1.03
Memory Test ok. ! 0000
Load :sys
2037 No bubble memory cards ERROR

SBP Monitor
>


(yeah yeah display at last still waiting to boot)

CPU rack now has got green lights Power and RUN both on ON state

So its bubble memory. Can there be any other cause?
Still there are no LED's on from SDU

[Algirdas]

replace all electrolytic capacitors on bubble memory card.
check it. Don't stuck on complicated ideas as old semiconductor technology or so. Look for bad contact, for leaking capacitor. Otherwise You will need to search for bubble memory module or Okuma's original CMOS memory replacement

[Motufaga]

Hello and thanks for contributions so far

Tested the bubble card capacitors,transistors ---all ok
Also dry joints but still could not discover fault on card.

Now looking for bubble memory card
OK got a quotation from OKUMA for $NZ3000 for the bubble module and $NZ3600 for its software.

There was a quote for $US1700 for refurbished memory card from USA.Will this need software? Is there any cheaper software out there?

Another quote received from Indonesia for a used(3 in 1) main board,bubble and main card for $US870. How good or how long can it last? Can I trust it?

I need to forward my recommendations for bubble card to my superiors.

Any contribution will be of great help.
Thank you

[Algirdas]

Tested the bubble card capacitors,transistors
isn't it cheaper to replace?
are there transistors on bubble memory card? I didn't noticed ever ...
used(3 in 1) main board,bubble and main card for $US870. How good or how long can it last? Can I trust it?
sure, You can. refer to me if in case
seriously: if it works, it can work for years and years. A lot of Okuma electronic hardware is working longer than 17 years without problem

[Motufaga]

Hi again,
Wake me up faster(chair)

I just discovered that the (2nd hand) bubble memory card that I referred to is used on TDK RX5B, STM machine.The machine was used to pick and place STM electronic components on PCB board.
The model numbers are the same as that of our LB9 CNC machine Main Board II B and bubble card, also main card I 3 which it houses.Bubble model no is E0227-702-008.$870US for the whole board is a good offer.

Please what all is required to run it on CNC lathe?
Compatible?
software(wedge)

PS Attached is a diagram of bubble memory card which i have not given up on testing.Maybe someone can identify a fault or something?

Any comments for or otherwise is welcome
Thank you

[Algirdas]

Attached is a diagram of bubble memory card
You forgot to attach the diagram. Picture however is useful, too. I see it is Hitachi made memory card, lucky you. It is really valuable item. Because it's possible to investigate and understand, how it works and to make your own, based on convenient SRAM chips.
And yes, it contains a transistor (or maybe more)
First what I would do is to replace voltage stabilizer 7812. Transistor B566 and all electrolytic capacitors.

[fordav11]

also bear in mind you will need proper equipment and some skill with PCB component replacements otherwise you will most likely make it worse. Most repair companies will not repair a PCB if it has been butchered by amateur.

First test for a dead short between power and ground. Find logic chip, such as 74LS245. put multimeter on continuity setting and put one probe on ground pin (pin 10 for LS245) and one probe on power pin (pin 20 for LS245). if reading is not 0-ohms there is no PCB dead short.

If you have dead short every component that is connected to power and ground (almost everything) will read shorted. Only way to find it is systematically remove components until short is gone. But note a dead short will usually mean one or more components are blown up.

You can test electrolytic capacitors using multi-meter (it must have capacitor test function) usually without removing them. Capacitance rating is written on side of cap (for example 50v100uf means 50 volts 100 micro-farads). If test reading (micro-farads) is out of range (+-10%) replace it with same type and voltage. Note electrolytic caps are polarised so check the orientation of the cap before removing it and line up the plus and minus pins correctly. If you put it in backwards it will explode!

B566 is common Bipolar Power Transistor. 7812 is common voltage regulator (converts input voltage in range +15v to +24v to output voltage +12v). These can also be tested in-circuit without removal. Test with multi-meter for dead short using continuity test function across each pin (1-2, 1-3, 2-3). when transistors fail they usually short out between emitter and collector pins. If your reading is not a short (0-ohms) or totally open (no reading) usually it's ok.

There are also common logic chips (74LSxx series) which can fail too, plus large Hitachi chips but those have unknown function/purpose (HD63501 is likely microcontroller). Also note XTAL. This is the clock source for the micro-controller. It can also fail resulting in no clock signal so PCB will appear 'dead'. Other discrete components like resistors and ceramic capacitors usually don't fail but can be checked in-circuit too. For resistors test using multi-meter on resistance test setting and then read colors on resistor and convert them to actual component rating compared to multi-meter reading. If reading is out of range by more than 10% replace it. Sometimes components will need to be desoldered one end to get a correct reading with multi-meter.

Diagnosing exact fault is very difficult for specialized hardware like this. Best you can do is slowly and systematically replace everything except Hitachi chips and bubble memory. If still not working then it can not be repaired. Hitachi chips and bubble memory are obsolete and new parts are not easily available now but can possibly be sourced from chip resellers via google search. However microcontroller contains CPU/RAM and custom-programmed ROM all in one chip so buying a new chip will not help you if that chip is faulty (very unlikely though)

Also remember when replacing components to not create broken track or damage otherwise it will never work even if you replace faulty component(s)