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Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Category: PC Tweakage

Remembering which tweaks worked

Anonymous 5 Axis Parallel Port Breakout Board Pinout

Parallel port breakout boards of this ilk run about $14, complete with cable, on eBay:

5 axis parallel port breakout board

The PCB has no part number and the inferred URL isn’t productive. The “driver CD” accompanying it has doc for every possible board the vendor might sell and, absent a part number, the file names aren’t helpful. An exhaustive search suggests it corresponds to the HY-JK02-M 5-axis interface board manual.doc file.

Despite any implication to the contrary, the board does not have optoisolators between the parallel port pins and the outside world. The stepper driver bricks should, but the input signals from limit switches and suchlike connect directly to the guts of your PC.

This overview (from the manual) shows the physical pin layout (clicky for more dots) and reveals the hidden silkscreen legend:

HY-JK02-M Breakout Board – overview

It looks like the board I got added a spindle relay driver transistor, plus a few resistors over by the manual control connector on the right.

Notice that the fourth terminal on each axis is GND, not the positive supply required for the optoisolators on the 2M415-oid driver bricks, which means you can’t just run a section of ribbon cable from the breakout board to the brick. You’ll need a separate +5 V (or whatever) power supply wire for each brick, with a common return to the system ground for this board. Those terminals are firmly bonded to the top and bottom ground planes on the board, so there’s no practical way to re-route them.

The small switch in the upper left, just to the right of the parallel port connector, selects +5 V power from the USB port (which has no data lines) or the power connector in the lower left. The LED near the switch won’t light up until you have both the parallel port cable and the USB cable plugged in.

The doc includes a timing diagram with no numeric values. I established that it can’t keep up with a 500 kHz pulse train and seems content at 100 kHz, but that’s conjecture. Setting the timing to match whatever the stepper driver bricks prefer will probably work. The diagram suggests the setup and hold times for direction changes are whatever you use for the minimum time between step pulses.

This shows the functional labels:

HY-JK02-M Breakout Board – function labels

The parallel port connector output pins, sorted by function:

Pin 9 1 2 14 16 3 7 8 6 5 4 17

Function Spindle
motor Enabled X step X dir Y step Y dir Z step Z dir A step A dir B step B dir

The parallel port connector input functions, sorted by pin:

X -Limit Y- Limit Z- Limit A- Limit Emerg Stop

10 11 12 13 15

The table uses Chinese for Pin 15: 急停.

It’s not clear whether the pins on the manual control connector are inputs or outputs, nor what the three separate Enabled lines do:

P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15

B step B dir A dir Z step Y step X step X dir Enabled 5V/VDD 5V/GND A step Z dir Y dir Enabled Enabled

The three white connectors in the middle drive an LED readout board that’s probably most useful as a DRO for CNC-converted manual mills using the pendant for positioning.

The small white connectors duplicate the functions of the green screw terminals. They’re probably useful in a small machine that I’m not building.

This isn’t the board I intend to use in the final setup, because I need far more I/O pins, but it’ll serve for the short term.

2013-02-17
Kill A Watt: IEC Adapters

I should have done this a long time ago:

Kill-A-Watt – IEC plug and socket

It makes measuring PC power consumption much easier!

I picked up some cheap AC plugs and sockets, cut a short IEC extender cable in half, and wired ’em up. If the IEC extender link breaks again, search amazon.com for something like “computer power cord extension” and rummage around.

IEC color code hint: brown = hot, blue = neutral (unless they cheat).

US NEMA 5 plug / socket hint: the blade marked W is neutral. More expensive hardware will have dark brass = hot, light brass = neutral, but don’t bet your life on it.

2013-02-13
LibreOffice 3.6: Fixing Font Selection Problems

This may not be a LibreOffice problem, but that’s where it shows up: the font selection dialog won’t display fonts with nonstandard Style names. There is, of course, no documentation anywhere (that I can find, anyway) on what Style names are permitted, so you discover this only when a font style that’s properly installed and accessible by other programs (like, say, Inkscape or Scribus) doesn’t render properly and doesn’t appear in the list.

In Xubuntu 12.10, LibreOffice 3.6.2.2 can’t handle the American Typewriter font style called Medium, which is what I’ve been using for the return address field on my (very few, these days) mail envelopes. Over the years, various versions of OpenOffice and LibreOffice have alternately accepted and rejected the Medium style, so this isn’t exactly a regression. It is, however, Yet Another Annoyance.

The solution, hinted at in that thread, involves using FontForge to rename the offending Style to, say, Regular, then saving the font. It’s actually the Weight property, hidden in Element → Font Info → PS Names tab. In this case, I changed the word “Medium” in the Fontname, Name for Humans, and Weight fields to “Regular”, which also updates the values in the TTF Names tab.

I save the modified font files in ~/.local/share/fonts using TrueType format, just to be sure I don’t confuse them with the original Postscript version in /usr/share/fonts/custom, delete the original, and then run fc-cache -v -f to update the caches. This surely isn’t the cleanest way to make it happen and almost certainly isn’t allowed by the Adobe EULA I agreed to, back when I actually bought the fonts, but so it goes.

And then It Just Works…

LibreOffice vs American Typewriter font

2013-02-11
Force-fitting a PCI-E Video Card in an Optiplex 780 SFF

I bought an off-lease Optiplex 780 in the Small Form Factor (SFF) version to replace my ancient Pentium D; it’s also available in Small Desktop Tower (SDT) and Ultra-SFF variations. The SFF box has two PCI slots and one PCI-E slot, which let me install a half-height dual-output video card, with results described yesterday. I innocently believed the PCI-E slot would have enough clearance for the video card, what with these things being standardized and all.

Turns out that the heatsink collided with a flange on the hard drive carrier, with about 5 mm of overlap. Fortunately, the bracket is plastic and I have no qualms about chopping up the hardware. A few minutes of Quality Shop Time removed a section of the offending flange and gave the video card just enough clearance:

Optiplex 780 SFF drive bracket

The heatsink reflects in the shiny surface of the carrier, with the scar from the missing flange just above that. The small dark-gray disk on the far left is a grommet holding a pin that supports the drive; it installs through the larger circular opening and snaps leftward.

You must install the video card and then snap the drive carrier into place. The heatsink protrudes above the flange, with the left side just barely clearing that grommet.

2013-02-10
Xubuntu 12.10 vs. Dual Monitors: Regression
It used to be that using two monitors with two separate X sessions in Linux actually worked. Then they improved things so it stopped working out of the box, but you could force it to work with a bit of effort. Further improvements made the workarounds more difficult. Now, with Xubuntu 12.10, it seems impossible.

This. Is. Not. Progress.

Experimenting will require considerable restarting of the X server, which nowadays requires, by default, rebooting the box. In the Bad Old Days, you could hit Ctrl-Alt-Backspace to restart the X server (and, en passant, blow away all unsaved data in your session). My suggestions about re-enabling it no longer work and, worse, the suggestions there about:
- Pressing Right-Alt + Sysreq + K
- Enabling DontZap
do not work, either. I’m no longer surprised by any of this.

Fortunately, as suggested at the same spot, this works:
- Create if missing: ~/.xprofile
- Add: setxkbmap -option terminate:ctrl_alt_bksp
- Make it executable: chmod u+x .xprofile
But it’s per-user, so it works only while you’re logged in, which means you can’t restart X from the login screen. This is marginally OK.

So. We begin.

This box (an off-lease Dell Optiplex 780, Core 2 Duo E8400 3.0 GHz) now has a Jaton GeForce GT430 nVidia video card with two DVI outputs.

In order to get decent performance, you must use the nVidia proprietary driver. Installing the nvidia-current package pulls in, as of this writing, 304. The nVidia driver now ignores the rotate option and the randrrotation option in xorg.conf. Adding the {Rotation=Left} meta-option to the portrait monitor or enabling Xinerama kills xrandr.

Not having xrandr used to not be fatal, but now OpenSCAD (among others) requires xrandr to be both present and active. Any solution that doesn’t allow xrandr isn’t feasible.

Despite notes suggesting that nVidia’s TwinView kills xrandr, it doesn’t (perversely, Xinerama should allow it and doesn’t; perhaps I misunderstand what’s going on). Add another line to .xprofile:
xrandr --output DVI-I-3 --rotate left
You discover which output to use by parsing the output of xrandr without any parameters:
```
$ xrandr
Screen 0: minimum 8 x 8, current 2650 x 1680, maximum 16384 x 16384
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
DVI-I-2 connected 1600x1200+0+0 (normal left inverted right x axis y axis) 367mm x 275mm
   1600x1200      60.0*+
   1280x1024      75.0     60.0
   1152x864       75.0
   1024x768       75.0     60.0
   800x600        75.0     60.3
   640x480        75.0     59.9
DVI-I-3 connected 1050x1680+1600+0 left (normal left inverted right x axis y axis) 434mm x 270mm
   1680x1050      59.9*+
   1280x1024      75.0     60.0
   1152x864       75.0
   1024x768       75.0     60.0
   800x600        75.0     60.3
   640x480        75.0     59.9
HDMI-0 disconnected (normal left inverted right x axis y axis)
```
Why DVI-I-0 and DVI-I-1 are disconnected is not explained. There is an HDMI jack that I’m not using, so that one does make sense. The output shows the portrait monitor on DVI-I-3 as rotated.

This is a single X session, so the two monitors show sections of a larger workspace. The cursor moves freely across the junction, it doesn’t vanish below the landscape montitor, and windows maximize properly to fill the single monitor they start in.

This is not what I want, because I cannot independently flip the workspaces on the two monitors. It’s possible to force one of the windows on the portrait monitor to “always on top”, but that means I have only one program accessible on that monitor, which isn’t usually the case.

This. Is. Not. Progress.

But it seems to be as good as it gets these days…
2013-02-09
XFCE Window Manager Recovery
The XFCE window manager, at least in its Xubuntu incarnation, seems surprisingly fragile. Every now and again, it won’t start up: all the auto-starting application windows pile atop each other on a single workspace, with no title bar or window decorations, with no way to move them around or change focus. In some cases, the mouse will be active and the keyboard will be dead. This is Not Good.

Rebooting that sucker isn’t productive, as the failure seems to occur most often after a normal system update that, inexplicably, clobbers the window manager’s state information. After that, the window manager will wake up dead every time.

The usual recovery technique involves activating a terminal window and entering xfwm4 --replace to forcibly restart the XFCE window manager, clear the state, and ensure it’s the default. That is remarkably difficult with a nonfunctional keyboard and can’t be accomplished remotely without access to the jammed user’s X session.

What has worked is to SSH in from another PC and delete the XFCE caches for the affected user:
```
cd ~/.cache
rm -rf xfce4
rm -rf sessions
```
You can blow away the entire .cache subdirectory if you prefer.

That this should not be necessary goes without saying. Remember that XFCE is currently the least-awful Linux Desktop Environment; all the rest have even greater complexity and much larger problems.
2013-02-01
Sanitizing A PC: Another Item For The Checklist

Just got another off-lease Dell, fired it up for the first time, and the BIOS presented this splash screen:

Optiplex 780 BIOS A06 Splash

Updating the BIOS from A06 to A13 restored the default Dell logo, but I really miss having a Genuine Lockheed Martin PC.

The Windows 7 Professional installed on the disk started up in “first time” mode, so they did scrub the drive. It does have RAID enabled, though, which may confuse the Linux installation I have yet to do.

I wish I could put my logo on the BIOS splash screen…

2013-01-29