[DaveD]

I've got a BMC-20, s/n BH8009039H, with a control upgraded to MAX 32. It has the twin-CRT text/graphics Ultimax console, and Fanuc spindle and servo drives. I bought it used, and have been having trouble getting it running.

The console, which had been working OK, developed a heat-related problem with the left-hand text CRT, losing sync after 5 to 10 minutes of power applied. The graphics CRT worked fine.

This machine uses a board in the console: "CRT Controller 2 PCB" (p/n 415-0174-002 Rev G) to create the video and sync signals for the text CRT only (apparently, the graphics CRT is driven by a daughter-board on the main CPU in the Multibus). I checked the video signals on the CRT Controller 2 board's J1 10-pin IDC ribbon cable connector, and found that the horizontal sync on Pin #7 was dead (should have been about 16.2 kHz square wave for CGA).

I figured I had a bad CRT Controller 2 board, likely a bad oscillator or divider chip, and that I would troubleshoot it later. Well, I finally got back to it and things are much worse:

When the power is turned on, all 20 green LEDs on the Ultimax console turn on steady and never turn off. The text CRT is blank. Pressing the "Graphic" button doesn't turn on the graphics CRT. The Multibus CPU is booting, and the power input strip TB52 on the console's distribution PCB has good DC power on it:
Pin #8: DC return
#7: +4.94 VDC
#6: DC return
#5: DC return
#4: -12.60 VDC
#3: +12.09 VDC
#2: +4.92 VDC
#1: +4.92 VDC

I'm really not at all sure what direction to go with this troubleshooting. Can someone help me out with a suggestion? I've got scopes, meters, and a fair bit of chip-level experience, but no spare boards.

Thanks very much!
Dave

[bloke]

What have you done to it since the last time you looked at it? Did you disturb any of the boards in the card rack?
It sounds like the boards need a bit of a re-seat in there. Also, your 5v is a tad low. It's best to run it a bit higher - around 5.25v at the power supply as there is always a bit of a drop by the time it gets to the console.

[DaveD]

What have you done to it since the last time you looked at it? Did you disturb any of the boards in the card rack?
It sounds like the boards need a bit of a re-seat in there.

I've done my best to recall, and I really don't think I've done any work on the mill since I found the dead HSync output. I haven't been into the Multibus chassis at all. I will go through and re-seat all the cards.

Also, your 5v is a tad low. It's best to run it a bit higher - around 5.25v at the power supply as there is always a bit of a drop by the time it gets to the console.

The Deltron DC logic power supply (Hurco p/n 4130008013) supplying the CPU chassis generates these voltages, measured directly off its output terminals:
+5.06 VDC
-12.52 VDC
+12.22 VDC
+24.55 VDC

I believe this one supply feeds +5V to both the Multibus chassis and all the way out to the Ultimax console. As I mentioned above, at the distribution PCB in the console I measured +4.94 VDC on the 8-pin terminal strip. This is the strip the wiring in the swing-arm connects to: the first thing the power wiring sees as it enters the console. I can raise the voltage at the Deltron supply terminals to +5.25 VDC, but I'm worried that this will damage the Multibus which is much closer to the Deltron supply and so as a guess will see about +5.20 VDC. I would like to make sure with you that this voltage is acceptable before I adjust the Deltron supply to +5.25 VDC at it's output terminals.

Thank you very much for looking at my problem; I'm very grateful for your help!

Dave

[bloke]

5.2v will be fine. We used to set all of these to 5.25v as a standard.

[fasto]

Your supposition about where the EGA graphics come from is correct, of course.

The CGA is generated on the CRT control board, as you suspect. This also deals with the LED's and the buttons, etc on the console. Communications with the main CPU is via RS232. Somehow* the main CPU tells this board what to show and it generates the CGA picture. The keys send characters back to the main CPU, thus, the Graphics key won't do anything if the CRT controller is kaput - as it won't send the main CPU the kepress. The trackball's encoders are handled by the personality board.

There is a way to test the CRT controller, but I don't think it will help you. Set sw8 on the DIP switch to OFF. You should see a blinking cursor on the bottom of the text screen. Pressing the keys should show various symbols on the text screen.

When you adjust the DC voltage, also check for AC ripple. Those electrolytic caps in the Deltron power supply are 20 years old!

It sounds to me like the CPU on the CRT controller isn't coming up out of power-on reset. I don't remember what CPU it is, likely an 8085 (that's what the axis cards use).

PS, I also have an '89 BMC20 with Fanuc drives and the original Ultimax2 control, serial# 201 (yours decodes to 903). I'd check the automatic oiling system thoroughly before running it much, all the metering valves were plugged on mine.

*The main CPU sends this via RS232 - this I know - but I haven't bothered to decode the protocol. I suspect the keypresses are simply sent as single characters back to the main CPU.

[DaveD]

Bloke and Fasto,

Thank you very much for both your replies!

1. I changed the 5 Volt output of the power supply to be 5.25 VDC at the supply's output terminals.
2. I checked for AC ripple on all the logic supplies, and found none greater than 2mV, which I thought was quite good for an older supply with such long wiring runs.
3. I reseated all the cards in the Multibus.

Unfortunately, the symptoms have not changed:

1. No CRT (text or graphics) display at all, ever. Totally black.
2. About 1 minute after power-on, when the initialization routine would normally briefly flash the 20 green LEDs on the Ultimax console: instead of just flashing, the LEDs stay on steady from that point until the power is turned off.
3. There is no HSync output from the CGA engine on the CRT Controller 2 PCB.
4. The CPU does seem to be booting, although the only real indication of that is the red LED bar graph on the front edge of the card: the bottom 4 LEDs are steady on, and the remainder are steady off, which seems to be normal.

However, I can add a new observation:

The Control Relay Board Assy (p/n 415-0224-001 Rev C) seems to receive it's 120 VAC power on it's TB1 (top left corner of board), Pin #3 and #5. Apparently, the Control Relay Board Assy controls switching of that 120 VAC power to TB1 Pin #4 and #6: it looks like these two pins are treated as outputs. The point is that the switch is never turning on: Pins #4 and #6 never get their 120 VAC power. Pins #4 and #6 are connected via a twisted pair of 14 AWG wire (red and white) down to a small power distribution terminal strip with 53 terminals on it and no label visible. It's tucked in among all the ice cube relays, 2 feet below the Control Relay Board Assy. The point is that none of the devices that are supposed to be getting 120 VAC power from this distribution terminal board working; they have no power. For identification purposes, one of these devices is the very small 24 VAC output transformer centered near the bottom of the cabinet.

So one question might be: what controls the Control Relay Board Assy's switching of the 120 VAC power from Pins #3 and #5 inputs, to #4 and #6 outputs?

Fasto, it's interesting that you also have a 1989 Fanuc-equipped BMC-20; apparently the Fanuc option was not widely purchased - we should form a club! I got mine from an auction of machine tools at Delphi in Flint, MI. I don't suppose yours came from that way, too? Anyway, thank you very much for the suggestions about the metering valves, AC ripple, and the CRT Controller Board. That CRT test with DIP Switch #8 is certainly good to know, but as you suspected it won't do me any good for a while yet.

I was wondering if anyone knew where I could get board schematics? I have none. At this point, even a signal listing of the terminal strips on the Control Relay Board would be tremendously helpful.

Again, I thank you both for your time and expertise on my problem. Any suggestions as to further troubleshooting will be gratefully accepted!

Dave

[fasto]

Hi Dave.
My BMC-20 came from a machine shop in New Jersey that replaced it with a newer machine. I don't know where they got it from. Yes Fanuc drives seem to be fairly rare, adding some insult is the triple servo drive was only used on Hurco machines as far as I can tell and used ones are SUPER EXPENSIVE as their sellers think they're gold plated. I've helped two other folks that have Fanuc drives, too, so there's at least 4 of us.
Seems to me that Hurco concentrated on designing and developing the CNC software (Ultimax and later versions) and hardware leaving the motion parts of the system to others. This is probably a good idea for a smaller company. It does result in some varied combinations of the drives on the various machines. I think Hurco were successful with their concept. The Ultimax software, even the 1980's version that I have, is vastly superior to any other control of similar age (except perhaps the 2100 control on some Cinncinatti machines). It's even capable of holding its own against modern controls for 2.5d stuff. The protection planes and graphics backplot are exceptionally helpful to a beginner like me, they've prevented errant keypresses from drilling holes in the table on several occasions. I haven't used the G-code side of the control, yet, though I will need to at some point to do some 3-d surfacing.

Re, the 120VAC output from the CRP board. You are correct, that's controlled from the main CPU. It's used to enable the servo drives and the other parts of the machine that are related, like the auto lube pump. The transformer in the middle bottom is for the work light.
This 120VAC output is supposed to be OFF until you activate it by pressing the POWER button on the console, so it's working correctly on your machine.

As far as I know there are no published schematics for any of the boards inside the machine. I have reverse engineered some of them to fix my machine - but not the CRP or the CRT controller. The machine manual that I have has wiring diagrams for some of the harnesses in the machine, and sometimes the signals are labeled (especially in the toolchanger controls). Do you have the manual, and diagrams therein?

I still think that your CRT controller board is kaput in some manner. I was looking on epay and there are 3 or 4 of these for around $200 for sale, you might want to consider one of them. I hate replacing boards unless there's a definite reason that I can find that makes them not work, though.

I don't know your level of experience doing board level troubleshooting of boards like this. I can test your CRT board in my machine, if you'd like. If you would rather get into troubleshooting over long distance, we can give it a shot.
Were it I checking this board, starting from no schematics, I'd pull it out of the machine, apply +5v and 0v (these should be easy to figure out), and check if the oscillator and main CPU are running. I just looked on mine - it's an 8085 CPU like I thought. (Man, did I ever design a lot of stuff around 8085s back in the day. I still have my 8085 ROM disassembler pack for my Tek 1240 logic analyzer, too.) Find an 8085 pinout and check the ALE pin, it should be pulsing at about 1/3 the clock frequency - which would tell us that the CPU is not stuck in reset and is at least trying to execute code.

FYI, the boards that I have done board level repairs and have reverse engineered to at least some extent are (1) Fanuc triple servo board; (2) Elstom monitor boards; (3) old-style 2-LED dual axis card; (4) personality board (the last 2 mainly to change faulty optocouplers).

[fasto]

Dave, I'm reading your last note again. You say nothing ever on both CRT's. Was it always this way, or did the graphics CRT ever show anything?

I ask because, on my machine, after the main CPU boots up it draws an "Ultimax" logo on the graphics screen. This does not seem to be related in any way to keypresses or anything else. Mind, I have the un-upgraded UltimaxII system, so I can't speak for the Max32.

It is possible that your graphics CRT is not working. Mine was not working when I got the machine, which I traced to a bad flyback transformer on the Elstom monitor board. It's also possible that something's amiss with the 12V in the control console, as (I think) this voltage is used only to run the two monitors.

You can easily check the monitor boards: open up the back of the monitor area (the back is hinged at the bottom and provided with a check strap). Each monitor board has a small fuse. If the fuse is blown the board probably has a bad horizontal output transistor and/or a bad flyback. Also, there's a large 2 Watt 1.1 Ohm resistor adjacent to the big heatsink in the middle of the board. If this is burned out you definately have a bad monitor board.

[DaveD]

Fasto,

Thank you very much for your detailed response!

On the graphics CRT: Yes, I do recall the Ultimax logo splash screen at boot time, back when things were working a bit better! I don't know why it no longer displays that screen, but I strongly suspect that all these problems are related.

The 8085 doesn't seem to be doing so well. Both ALE (pin 30) and RESET_OUT (pin 3) have nothing but 100mV of noise on them. On the input side, /RESET_IN looks fine: +4.96 VDC and steady, and CLK_(OUT) is a reasonable looking 4.40 volt square wave at 3.2 MHz, which I'm pretty sure is right for this version: 8085AH was speced at 3 MHz system clock, and the stamp on the crystal confirms this: 6.1440 MHz, where the system clock runs at crystal/2.

Isn't RESET_OUT supposed to just inversely follow /RESET_ IN, with state transitions synced to the system clock? Also, as you pointed out, the manuals seem to think that most instruction cycles require ALE to be asserted when the lower address byte is stable, so ALE should have a fairly regular square wave on it, right?

The only other thing I've found of interest is on the CRT Controller 2's DC power input jack: J4. When looking at the voltages with a scope, I found an anomoly on Pin #3:

Color Pin# Voltage Measured
===== === =============
Gray 1 DC Return
Yellow 2 +5.11 VDC
Blue 3 +3.86 VDC
Brown 4 +12.20 VDC
Orange 5 -12.60 VDC
Gray 6 DC Return

So, what the heck is going on with this +3.86 volts on Pin #3?

I appreciate your comments and insight into Hurco's practice of buying other mainstream equipment and integrating their software, castings, and "glue". I am a fervent supporter of playing to one's strengths. In the late 1970's, I worked for an older company that designed virtually everything in-house. Switching power supplies were gaining acceptance, so our engineering VP decided we should design our own switchers - at the time, a black art. We tried. Really hard. Not so good. Turns out making a switcher that would turn on wasn't really all that hard; it was making one that ran for more than 3months that ate our lunch. Bloody and scarred, 2 years later, we gave up that plan and started buying (working) switchers from a company that made nothing but power supplies. I've never forgotten that lesson, and so I'm all in favor of companies that build the parts they know most about and buy the rest.

I have a side question, if I may? The bottom port on the Intel CPU card in the Multibus is supposed to be for a keyboard. Do you know what the functional use of that is? If it comes up with the Intel monitor prompt, is that useful for diagnostics? Also, I assume the EGA video daughterboard is the monitor output; or is the TX pin on the port supported for a TTY?

Thanks very much for your patience and help!

Dave

[bloke]

This could just be a corrupted hard drive. The text video signal is sent to the monitor from the personality card. For it to display anything, it needs to see a file called INT10.exe to run the display.
Do you have the floppy disks for this machine? If so, boot the control with the Executive disk 1 in the drive and see if the floppy light stays on while loading and whether the display appears.

[DaveD]

...Do you have the floppy disks for this machine? If so, boot the control with the Executive disk 1 in the drive and see if the floppy light stays on while loading and whether the display appears.

Bloke,

Thanks very much for your reply! I think our last 2 messages passed each other in transit.

I received these 5 diskettes with the BMC-20:

1. Disks 1 through 3 of: "Max 32 DA Version 1.61, Max32 DA Upgrade Package, Part # 007-4121-011, Serial # M32A900207BA, ENG"
2. A user-made diskette: "Hurco Machine Configuration BH8009039H"
3. Optikey Utility Diskette - Rev J, Production Pkg, 007-4137-001, PKG, SKCMX152 #1 PROD"

Are any of these disks the same as Executive Disk 1? If not, what's the best way to get one?

Thank you!
Dave

[bloke]

The blue wire to pin 3 of the CRT controller is labelled RST so I'd assume it's a reset line. Maybe removing this wire temporarily will let it display something. It's not something I've seen be a problem before.

The Executive disks are the ones marked as Max32 DA V1.61. The config disk holds all the information about the machine and the Optikey disk allows you to run software from V1.52 up to V1.64.

[DaveD]

Bloke,

I lifted the blue RST wire, and rebooted. It didn't make any difference that I could see. Certainly worth a try. By the way, with the blue wire disconnected the CRT Controller 2 Board tied that connector pin to +5 volts. I suspect that the other end of the blue wire has an open collector switch that, when enabled, draws down the signal and resets the CRT Controller 2 Board. That's only a guess.

I then rebooted off the #1 "Max32 DA V1.61" disk. The diskette drive's stepper motor sounded like it was successfully reading tracks (not constantly resetting). After a minute or so, the stepper stopped moving, but the green light on the diskette drive stayed on. I gave it about 5 minutes, but when nothing changed I assumed it was waiting for disk #2 of 3. I put in disk 2, and the stepper started moving again. After about 15 seconds, the stepper stopped, and the green light on the diskette drive turned off. I'm assuming that represents a successful boot. At the end, all 20 green LEDs on the Ultimax Console were steady on. Neither CRT had any display visible; they were both completely black. It doesn't look any different from when we were booting normally off the hard disk drive, so unless you say otherwise, I'm going to assume the hard disk drive is working OK.

Fasto,

I checked both + and - 12 volt lines in the Ultimax Console with a scope, they both seemed good and noise-free. I also checked the fuse and resistor you mentioned on both CRT monitor boards. They all seemed fine.

I thought I'd try and splice into the serial comm between the Personality Module and the CRT Controller 2 board and attach a data scope. At the CRT Controller, Fasto mentioned that the data comes in on the P1 connector. I took a look at it, and it looks to me like this:

Pin#4, Green, TxD Data from CRT Controller 2 to Personality Module.
Pin#6, Black, RxD Data from Personality Module to CRT Controller 2.
Pin#8, White, Request To Send (/RTS) from CRT Controller 2 to Personality Module.
Pin#10, Brown, Signal Common.
Pin#13, Red, Not Connected - no trace on CRT Controller 2 PCB.

I did not have time to attach the data scope, I need to build an edge-card connector adapter set for P1. I will report back with what I find; I'm hoping that there's good data arriving from the Personality Module, and that the problem is somewhere on the CRT Controller 2 Board.

If either of you can think of anything else I can try, I'd be very grateful.

Thank you very much for all the help!
Dave

[bloke]

Another thing to try would be to remove the two dual axis cards from the slots in the card rack. Just slide them out of the slot about an inch. If one of these has a fault, it may stop it booting.
Bear in mind that if it does come on, it will run slow.

Have you had this machine running before?

[fasto]

Fasto,

Thank you very much for your detailed response!

On the graphics CRT: Yes, I do recall the Ultimax logo splash screen at boot time, back when things were working a bit better! I don't know why it no longer displays that screen, but I strongly suspect that all these problems are related.

I am not convinced of this. I think you've got the classic layered problem scenario.

The 8085 doesn't seem to be doing so well. Both ALE (pin 30) and RESET_OUT (pin 3) have nothing but 100mV of noise on them. On the input side, /RESET_IN looks fine: +4.96 VDC and steady, and CLK_(OUT) is a reasonable looking 4.40 volt square wave at 3.2 MHz, which I'm pretty sure is right for this version: 8085AH was speced at 3 MHz system clock, and the stamp on the crystal confirms this: 6.1440 MHz, where the system clock runs at crystal/2.

Isn't RESET_OUT supposed to just inversely follow /RESET_ IN, with state transitions synced to the system clock? Also, as you pointed out, the manuals seem to think that most instruction cycles require ALE to be asserted when the lower address byte is stable, so ALE should have a fairly regular square wave on it, right?

I'm assuming that you used the scope to look over these waveforms, not a meter, as a small amount of AC is what I'd expect to see using a meter. I had to get out the 8085 data book to refresh my memory on this.
RESET_OUT is supposed to track !RESET + some clock cycles, it should go high a few clocks after !RESET goes high.
ALE is never tri-stated - as long as the CPU is not in reset, and READY is high, and HOLD is low, ALE should pulse high for 1 clock every 3 or 4 clocks (depending on which T state the CPU is in).
If neither of the things are happening there's quite obviously something amiss with this board. Does anything look burned up? I found about a half cup of dustlike chips inside the console on my machine.

The only other thing I've found of interest is on the CRT Controller 2's DC power input jack: J4. When looking at the voltages with a scope, I found an anomoly on Pin #3:

Color Pin# Voltage Measured
===== === =============
Gray 1 DC Return
Yellow 2 +5.11 VDC
Blue 3 +3.86 VDC
Brown 4 +12.20 VDC
Orange 5 -12.60 VDC
Gray 6 DC Return

So, what the heck is going on with this +3.86 volts on Pin #3?

I would probably have a look at where that trace leads on the CRT controller. Should it go into some TTL inputs (which I expect) it may need to be driven high or low to make something work.

I appreciate your comments and insight into Hurco's practice of buying other mainstream equipment and integrating their software, castings, and "glue". I am a fervent supporter of playing to one's strengths. In the late 1970's, I worked for an older company that designed virtually everything in-house. Switching power supplies were gaining acceptance, so our engineering VP decided we should design our own switchers - at the time, a black art. We tried. Really hard. Not so good. Turns out making a switcher that would turn on wasn't really all that hard; it was making one that ran for more than 3months that ate our lunch. Bloody and scarred, 2 years later, we gave up that plan and started buying (working) switchers from a company that made nothing but power supplies. I've never forgotten that lesson, and so I'm all in favor of companies that build the parts they know most about and buy the rest.

Years ago when I worked for a contract engineering firm we were hired to invent a switch-mode battery charger for EV use. I was assigned because I was the most junior engineer - never a good idea with something as complex as a switcher. I could probably just get it to work in a satisfactory manner today, 20 years later; obviously it was a huge failure then!

I have a side question, if I may? The bottom port on the Intel CPU card in the Multibus is supposed to be for a keyboard. Do you know what the functional use of that is? If it comes up with the Intel monitor prompt, is that useful for diagnostics? Also, I assume the EGA video daughterboard is the monitor output; or is the TX pin on the port supported for a TTY?

Thanks very much for your patience and help!

Dave

I have the original 8086/8087 UltimaxII system, which I don't think has a keyboard port. I've never looked at it closely. There is a small daughterboard with a (probably obsolete) NEC LSI on it to generate the EGA graphics. There's also a serial port daughterboard, which I think is where the CRT controller is connected though I am not sure of this.

Bloke's idea of pulling out the axis cards is a good one, and on my machine I'd pull out the disk controller card - which I don't think you can do. UltimaxII boots from a bank of EEPROMs not a disk.

Is your EGA output doing anything? Sync or video? Even with the screens blanked I believe both sync signals are active and the video signal is supressed.

[bloke]

The keyboard connector was mainly used for setting parameters in the BIOS, copying files and folders when setting up the hard drive. This can be done on the Max32 controls, but was a lot easier just to jam the drive in a desktop PC and set it up there.

Another thought crossed my mind last night. Do you get a cursor back on the text screen if you pull out the hard drive card?

[DaveD]

Bloke and Fasto,

Hey, some good news! The control is booting, the Graphics Screen displays a "Max32" splash screen, and 17 of the 20 green console LEDs turn off at the end of the boot sequence; the remaining 3 are supposed to be on (Tool Changer in "Manual", the "Graphics" LED, and one other I can't recall).

I tried pulling the dual axis boards and the hard drive card, but the system did not improve. I also traced the blue pin#3 wire on CRT Controller 2's DC power input jack J4 and you were both right: that line is pulled up to +5V by R27, and then it goes directly to the pin #36 /RESET input of the 8085. So, whatever is on the other end of that blue wire (+20 feet away!) is not trying to continuously reset the 8085, which is clearly a good thing.

So, I was a bit stymied, and thought I'd work some on the serial comm between the Personality Module and the CRT Controller 2 board's P1 connector. I mentioned earlier that I wanted to attach an analyzer to see if the Personality Module was sending any data to the text CRT, and Fasto mentioned that the data comes in on the P1 connector.

I spliced in a pair of DB-9S / DB-9P connectors, and broke the line open. My protocol analyzer refused to turn on (I love it when the tools break) and so I used Hyperterminal on a laptop to look down the data link towards the Personality Module. I powered up the Hurco, and a minute later I had a successful boot! Graphics CRT running, LEDs behaving...Happy Days!

So, here's my Big Theory of Everything: the Personality Module looks at the CRT Controller 2 at boot time. If the TxD line from the CRT Controller 2 doesn't show an idle mark (-12 VDC) or, possibly, if RTS isn't asserted by the CRT Controller 2, then the Personality Module decides the whole operator console is toast and refuses to turn anything on (Graphics CRT, 20 LEDs never get out of "test on" state, etc.) Anyway, that's my theory. Feel free to burst out laughing and shoot holes through it.

So I've got to troubleshoot the CRT Controller 2 PCB. I will post here about my progress, or lack thereof.

By the way, can either of you tell me the communications parameters (baud rate, data bits, parity, stop bits) of the serial link between the Personality Module and the CRT Controller 2 board? It only spits out a few characters at boot time, and I don't have a working analyzer, so I'm trying to catch data on a scope and make guesses as to what parameters to setup Hyperterminal with. I clearly don't have it right yet, because Hyperterminal is showing received data that's gobbledygook nonsense.

Thank you both very, very much for all the assistance you've given me so far. I'm very relieved that the Hurco is close to running again!

Dave