BMC-20 with Max32 upgrade - console fails at power-up.

[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