LB9 CNC lathe- No display from Monitor and VACIII unit

[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

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

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)

[Motufaga]

Hello

yes,yes my mistake I meant picture.Many more thanks Algirdas and also to you Fordav11 for the tutorials.

Last time an electronic tech and I removed the capacitors and tested them and they were within range.For the transistors we tested them on the board.

This time I removed and tested the first transistor B566 to be faulty. (I was careful not to butcher!!.....)

I also tested the IC's, all have similar configuration for GND and Vcc. .... no continuity, Great, thanks for the tips.

Today I could not find transistor B566 in my island so I bought a complementary one, transistor D476.

From the data sheet 2SB566(K) is a "Low frequency power amplifier power switching complementary pair with 2SD476(K) and 2SD476A(K)."

Please help.Complementary??I cant figure out...Does that mean a substitute for B566??

I wanted to test it but I thought to be safe,post this first.

Else I have to buy transistor B566 online.

Any suggestion welcome
Thanks again

[fordav11]

I have not looked up your equivalent but the specs on the 2SB566 are 70v 4A 40w 15mhz.
Best replacement is TIP42C
If the specs on your equivalent are similar or a higher rating to above then it can be used.
Otherwise buy the TIP42C which is very common.

[Motufaga]

Bula from Fiji
Thanks Fordav11 and I got TIP42C as replacement for 2SB566(K). I got an electronic tech to help me out and we replaced it twice.Both times the Control ON/Reset switch was ON for 10 to 15 seconds before tripping OFF. Same error showing up again but it took longer to trip OFF than before.
Now Im trying to figure out the other fault connected to this transistor line.

The voltage regulator HA17812P was tested to be working OK.
And that 2SB566(K) is PNP(with -ve specs) and its complement 2SD476(K) is NPN (with +specs).

Until then
Thank you and bye

[fordav11]

the B566 was likely not faulty. try removing various other transistors/regulators and see if powering on doesn't trip out. then you will know what part is causing the problem.