Dead Text Screen on Hurco BMC25 with Max32 (Ultimax2)

Ternent · Apr 19, 2016

I bought a BMC25 a few years back direct from Hurco . It has Ultimax 2 ( Max32 ) control. The machine has a fault at present and the text display has stopped working. I have tested both of the CRT driver boards at the rear of the CRTs and have replaced 8 capacitors which were measuring outside of specification. Other than that I could not find any fault with the boards. The graphics screen displays as normal and the machine appears to be working normally, with the exception of the text display screen which is completely blank. If I take the ribbon cable which feeds the graphics CRT driver board and plug it into the text screen CRT driver board I can get graphics display on the text CRT, so I'm sure the CRT is working correctly.
I have adjusted the main power supply voltages to get the correct 5V and 12V levels. Is there any way to identify if the problem lies with the CRT display controller board ( 415-0174-001L) or the CRT driver board at the rear of the CRTs. I do not want to buy replacement boards unnecessarily.
If there are any other tests that you could suggest or perhaps a way to get the text to display in another way so that I can use the machine I would be very grateful.

Roooster · Apr 19, 2016

More than likely the CRT controller card. Even if the Cable that supplies the data was borked, it should still show a flashing cursor.
I've got a tickle in the back of my brain that tells me I repaired a CRT controller for this fault years back by replacing a 7400 or 7404 IC. We still keep the boards in limited quantity.
Don't swap the cables over for too long as you can damage the CRTs as they have different scan rates.

Ternent · Apr 27, 2016

I've replaced the CRT controller card and the fault is still the same. All I can think to do now is to replace the Text CRT driver board. Any suggestions for which components fail on those boards. I've already replaced all of the caps that were out of spec.

gregormarwick · Apr 27, 2016

There is a small axial leaded fuse soldered to the CRT driver board next to the ribbon cable header. I've replaced it on two different machines, no idea why it might blow but it does.

jakefreese · Apr 27, 2016

I've got an ultimax3 control in the box. The monitor worked when it was powered down. I had a dead hard drive. I want to move the boards.

Sent from my XT1254 using Tapatalk

Davis In SC · Apr 27, 2016

jakefreese said:
I've got an ultimax3 control in the box. The monitor worked when it was powered down. I had a dead hard drive. I want to move the boards.

Sent from my XT1254 using Tapatalk

Was the cost to replace the Hard Drive a killer ? I think my Ultimax 3 HD is bad.

jakefreese · Apr 27, 2016

Decided it was retrofit time. I had some challenges with the PCB3 board which was making the tool changer act up, it was just time.

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Roooster · Apr 28, 2016

Hang on..
You said it was Max32. Are you connecting the old ribbon cable to the CRT controller or the litte grey cable that links it to the 50way D-plug on the cable connect board under the keyboard?
Is the plug the right way round?

Ternent · Apr 28, 2016

It is Ultimax 2 with MAX32 conversion. If I plug the graphics ribbon cable into the text screen driver board I get a graphics display on the text screen but it is wrapped around which is what Id expect. If I plug the text ribbon cable into the graphics driver card I do not get anything on the graphics screen. That is why I thought it must be the CRT controller card.
Ive now replaced the CRT controller card ( blown all of my pocket money ) and still no change.
I have checked the ribbon connections and it is connected the right way around.

Ternent · Apr 28, 2016

One thing I haven't tried yet is to turn the ribbon cable around as Hurco say that they only use one side of the connector.

Ternent · Apr 28, 2016

Ive connected pin 1 to pin 1. I will double check though as I was surprised that many of the connectors can be fitted either way around. The original CRT controller card was an 001 board and Ive replaced it with an 002 board. Ive checked the supply to the board as per the Hurco service bulletin and all is correct.

gregormarwick · Apr 28, 2016

Your CRT controller card is 415-0174-002? Just want to make sure as I'm not familiar with the Max32 upgrade...

If yes, there are two jumpers (X1A, X1B) in the upper right quarter of the board. They should both be installed normally.

If you remove jumper X1B and start up the machine the diagnostics will be displayed on the graphics screen, and will tell you if the communications with the CRT controller board are functional or not.

Ternent · Apr 28, 2016

gregormarwick said:
Your CRT controller card is 415-0174-002? Just want to make sure as I'm not familiar with the Max32 upgrade...

If yes, there are two jumpers (X1A, X1B) in the upper right quarter of the board. They should both be installed normally.

If you remove jumper X1B and start up the machine the diagnostics will be displayed on the graphics screen, and will tell you if the communications with the CRT controller board are functional or not.

It had a 001 board fitted but I managed to get a new old stock 002 board, which came with the required orange connector to make the conversion. I left jumper X1A open as we have 50hz electrics in the UK. I tried booting up with jumper X1B on and off but still couldn't get the screen to start up. I think that the CRT driver board isn't firing up as I have tried measuring some voltages at the same points on the graphics driver board and the text driver board. I found that there is no high voltage at the focus pot when the screen should be displaying text but on the graphics driver board at the same point I get a reading of 400V.
Similarly if I plug the graphics ribbon into the text crt driver board the voltage at that same point goes to 400V. I am thinking now that the text driver board is not firing up the high voltage side. When measuring the voltage around the 555's I find that I get a higher voltage on the graphics driver board than on the text driver board. Is there any way to check the signal from the ribbon cable to confirm that the CRT controller board is sending a signal.

gregormarwick · Apr 28, 2016

Ternent said:
It had a 001 board fitted but I managed to get a new old stock 002 board, which came with the required orange connector to make the conversion. I left jumper X1A open as we have 50hz electrics in the UK. I tried booting up with jumper X1B on and off but still couldn't get the screen to start up. I think that the CRT driver board isn't firing up as I have tried measuring some voltages at the same points on the graphics driver board and the text driver board. I found that there is no high voltage at the focus pot when the screen should be displaying text but on the graphics driver board at the same point I get a reading of 400V.
Similarly if I plug the graphics ribbon into the text crt driver board the voltage at that same point goes to 400V. I am thinking now that the text driver board is not firing up the high voltage side. When measuring the voltage around the 555's I find that I get a higher voltage on the graphics driver board than on the text driver board. Is there any way to check the signal from the ribbon cable to confirm that the CRT controller board is sending a signal.

Leave X1A closed. Both my Max 2's have X1A installed and they work properly - as you can see I'm also in the UK.

Connecting the CRT controller board to the graphics screen would normally cause the graphics screen to power up and display an image, but not readable.

Ternent · Apr 28, 2016

gregormarwick said:
Leave X1A closed. Both my Max 2's have X1A installed and they work properly - as you can see I'm also in the UK.

Connecting the CRT controller board to the graphics screen would normally cause the graphics screen to power up and display an image, but not readable.

Thanks Ill change the setting to 60Hz X1A closed and see if I have any joy.

Roooster · Apr 28, 2016

Can you post a pic of your 26 way connector to the CRT controller when it is installed in the machine?

Ternent · Apr 28, 2016

Roooster said:
Can you post a pic of your 26 way connector to the CRT controller when it is installed in the machine?

sorry I don't have a picture but it is installed so that the label is uppermost and the green wire is connected to pin2. I have measured the voltage at each wire ( with the connector disconnected from the board ) and the voltages are as follows
Green 0v
Black -12v
White 0v
Brown +11.7v
Red +11.7v
I think it's unusual that both the white and green show 0v so could it be that there is no signal going to the CRT controller board

Ternent · May 5, 2016

Is it possible that the 002 CRT controller board is hanging the system because my original 001 CRT controller board was for the Max32 conversion.
Im currently worried that I could have bought a faulty Controller card. Is there a test that I can do to make sure it isn't just a dead replacement board. If it is faulty I need to get it back to the supplier ASAP.
I Have checked the DC voltages but could check the signals with my scope if I knew what I should be looking for.

Roooster said:
Hang on..
You said it was Max32. Are you connecting the old ribbon cable to the CRT controller or the litte grey cable that links it to the 50way D-plug on the cable connect board under the keyboard?
Is the plug the right way round?

Roooster · May 5, 2016

Where are you in the UK?

Ternent · May 6, 2016

Roooster said:
Where are you in the UK?

Im in Durham in the North East.

Dead Text Screen on Hurco BMC25 with Max32 (Ultimax2)

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