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(Year 2005) |
Today
At the time of this writing music and moving video are stored on
media looking very similar.
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History
Once upon a time, a long long time ago, music was stored on big black
things. During that age moving video was stored on tape in cassette.
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My old VCR
I happened to have one of those old relics from the past.
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Connectors
It was a high tech VCR with Nicam stereo. It seemed to have dual SCART
connectors, but only one of them was really usable.
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The inside
Nothing here is useful, everything has to be replaced...
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Drives
The tape mechanism is replaced with a dual layer DVD±RW and a 250 GB
Seagate Barracuda. The 3.5" HD is mounted in a 3.5" to 5.25" converter
to make it fit better to the DVD drive.
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Electronics
The electronics is replaced with two PCI cards, one for DVB-T and one for
DVB-S. Everything is connected to a VIA mini-ITX motherboard running a
1 GHz eden fan-less CPU.
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Short of space
Due to lack of space the DVB-cards has to be placed below the
motherboard. The only PCI slot on the motherboard is connected to a PCI
riser card with two PCI slots by a flexible PCI cable. Yet another
flexible PCI cable is used to connect one of the PCI cards to the riser
card.
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Will it fit?
I was able to get the drives and the cards into the box, but all those
cables... Connected to the back of the box is audio in and out to the
both SCART connectors. Also, the upper SCART has S-video out and
composite video in. The lower SCART has composite video out and S-video
in. Next to the SCART connectors there is a switch to select video input,
the DVB-T card has one, but only one analog input.
Other connectors on the back are SAT-in, antenna in, keyboard, VGA,
network and coaxial and optical SPDIF.
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VGA cable
As the motherboard and DVB-cards are built into the box cables are
needed to connectors at the back of the box. Soldering a VGA cable is no
fun, so I thought that I would save half the work by buying a ready made
VGA cable. That way I would only have to solder one end. Unfortunately,
it turned out that the cable of brand Wiretek bought at Clas Ohlsson
didn't have pin 12 and pin 15 connected. I had to fix that myself with
extra wiring. Pin 12 and 15 are used for DDC signals, without these the
computer is unable to ask the monitor about name, resolution and refresh
rates.
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It did fit!
Yes! It did fit! At least it kind of did fit, the top of the box is no
longer exactly flat...
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Time to boot
As you can see, the hardware work isn't finished yet. There is still room
for some kind of VFD display, and as a VHS tape was wider than a DVD
drive the front now has a hole that has to be filled.
I've made some minor testing booting knoppix during the
building of this machine, verifying that it could see the PCI cards and
the drives. But once all was put together the machine simply refused to
boot. At power-up the HD would spin up, but that was all. No video signal
on the VGA port, no beep from the motherboard, no nothing.
After taking everything apart again I could see that one of the flex
cables for one of the PCI extenders had come loose. Once that was put
back in place the machine booted knoppix without problem. The drives
were found and the PCI cards were found in /proc/pci.
I kept the machine running for some hour in knoppix and checked the
temperature of the HD which then was 49 °C. That is pretty OK for a
box without any fan at all, but the drive had only been spinning idle
all the time.
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Short circuit
At the next boot the PCI cards were no longer found. It turned out that
during my short burn in test the flat cable to the DVB-S card had been
penetrated by a sharp soldering pin from the DVB-T card. That cable now
had a short circuit between two pins. The problem is marked with a red
circle in the picture above.
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Replacing the flat cable
I sacrificed an ATA-133 cable to replace the broken flat cable.
There is no way to make everything fit into the box without those
flexible PCI extenders, but they have caused me a lot of trouble and
seem to cause me even more trouble.
It now seems to be more or less random if all PCI cards will be found
by BIOS at boot. I don't know if this is because of the fact that the
PCI bus wasn't specified to have a 7 cm long stub. Things are probably
not getting better by the fact that I'm using two 7 cm PCI extenders. It
could also be that something got damaged when half of the PCI bus to one
of the cards disconnected or when there was a short circuit between two
pins on the PCI bus and a pin on one DVB-card which probably was
connected to ground.
If it is hard to find those cards during boot I wonder how things are
going to work when the cards will send a lot of data on the PCI bus.
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Padding
To avoid another short circuit I added some padding to the DVB-T card.
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Operating system
I installed Slackware current
which probably soon is going to be Slackware 10.2. During the
installation I basically followed the first steps at
www.edafe.org/vdr.
X.org version 6.8.2 which was included in Slackware current did not out
of the box support the XvMC extension which was needed
for hardware acceleration of MPEG2 decoding. So I realized that I would
have to recompile X for that.
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Hardware acceleration
I found a really nice
project which used a
motherboard similar to mine. On that page it was said that it was a
P.I.T.A. to get the MPEG decoder and hardware OpenGL acceleration to
work. After having read that I realized that I should also get
hardware accelerated OpenGL to work :-). After following the instructions
in the VIA Unichrome and DRI HOWTO I had it all working.
Without hardware acceleration glxgears gave about 70 fps.
With hardware acceleration it gave about 630 fps. I don't think
hardware 3D acceleration will be to any use in my application, but at
least I know that I'm able to use it if I would like to.
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First TV picture
After using /usr/src/linux-2.6.12.3/Documentation/dvb/get_dvb_firmware
and installing the downloaded firmwares to /lib/firmware it seems as if
both DVB cards might be working. Some day I might get myself a satellite
dish to test the DVB-S card, but the DVB-T card is definitely working.
I used the linux-dvb-apps-1.1.0 utilities from
http://linuxtv.org/downloads
to tune into a channel and was then able to copy directly from a
dvb device to a file. That file was then copied to another machine
in my network, where it turned out to be an mpeg2 file playable with
mplayer :-). The file had a resolution of 720x576 and seemed to be
25 fps non-interlaced images. The pixels were not square as it had
wide-screen format.
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VDR
As VDR seems
perfect for this kind of DVB appliance I started by installing that
software. I was planning to use the softdevice plugin for output as I
don't have any full featured DVB card. Unfortunately it turned out that
softdevice didn't support XvMC on my VIA unichrome graphics. Instead I
had to use the xine device plugin.
I really did like the OSD of VDR. I also really liked that there was a
lot of plugins for VDR. Unfortunately, when looking on tv the frame rate
wasn't smooth. Also VDR segfaulted a lot.
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LIRC
LIRC was configured to use the remote
that came with the Avermedia DVB-T card. I liked the remote which
belonged to my old video, but unfortunately I wasn't able to use that
with the Avermedia card.
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More segfaults
Trying to use my remote and LIRC together with VDR caused VDR to
segfault instantly. All these segfaults made me look for some software
to replace VDR.
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Freevo
Freevo seemed like a nice piece of
software even though it wasn't optimized for DVB. Installing Freevo was
a lot of work compiling a never ending chain of dependencies of python
and perl modules. Once it all was downloaded, compiled and installed
Freevo refused to start claiming that a module that I had installed
still was missing.
It turned out that Freevo wanted an older version of Python than the
latest stable that was included with Slackware. Once I had installed that
older version and recompiled the python modules I was able to start
Freevo. Freevo can use mplayer or xine for output. I was able to compile
them both with support for XvMC, but only xine was able to show any
picture with XvMC.
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Heat problem
Freevo was a lot more stable than VDR. It didn't segfault and the
remote worked fine with LIRC. I also really liked the TV guide
in Freevo. Still the system wasn't usable because of a varying framerate
and distortions in the picture. The current stable version of Freevo
also has the drawback that it only supports one DVB card.
I reverted back to record a file with dvb-apps once again. This time
the recorded file also had distortions and a varying frame rate. The
recorded file also caused mplayer to segfault.
It seems as if the DVB-T card is able to deliver a valid mpeg stream only
for about a minute before it gets hot. This probably also explains some
of the segfaults i had with VDR. My video obviously needs some cooling.
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Space needed for a fan
How will I get a fan into this small box filled with far to much already?
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(Year 2006) |
40 mm fans
I bought two tiny 40 mm fans and used an old box which had been used for
cotton buds.
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Fans in place
A saw was used to reshape the old cotton buds box to something completely
different. As the width of the box was 80 mm the box was perfect for this
purpose.
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Below the motherboard
The fans are completely below the motherboard. I was pleasantly surprised
that I couldn't hear them running even when the cover was off. However,
I wonder if they are enough to cool the system...
I will never know if the fans are enough to cool my hot PCI cards.
After reassembling my video, once again the PCI cards were no longer
found by the system. Several attempts to disassemble and reassemble my
video didn't help. Obviously something is broken with my PCI bus and
it seems to get worse each time the video is taken apart. I suspect the
flexible PCI cables to cause my troubles, but now I'm giving up the PCI
cards. I intend to take a pause in this project, then I will buy USB
DVB devices instead.
It is hard to find good USB devices. They have to be small and at
least one of them should have the remote IR receiver on a cable so I can
place it where it belongs in the video. I need one DVB-T and one DVB-S
device and they should have good support in Linux.
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(Year 2007) |
MythTV
After about a year, mostly by a coincidence I started my old video. To
my surprise it found the both DVB cards on the PCI bus and I decided to
make some new attempts to get it working.
I have previously tried VDR and Freevo and I have avoided MythTV as
I had the impression that my motherboard would not be powerful enough for
MythTV. I was pleasantly surprised to see that MythTV seemed to work fine
with my slow motherboard as a it doesn't have to compress the video
stream from a DVB cord.
MythTV is really nice, it seems to
have all the advantages of both VDR and Freevo. I think I will stick
with MythTV in my old VCR.
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Matrix Orbital VFD display
MythTV supports an LCD display with
lcdproc. However a simple LCD display
would not be good enough for my old VCR, I decided to buy an expensive
VFD display from
Matrix Orbital. The display
is called LK204-25 and is connected to a serial port.
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Behind display window
Somehow I will make the display fit behind the display window...
During this entire project it seems as if every part has almost fitted
into the VCR box, but finally I have been able to make it fit in some
way.
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Cut off a corner
I had to remove some plastic from a tight corner to make the display fit.
One of the advantages with the Matrix Orbital display is that it is
possible to connect buttons to connectors on the display circuit board.
When those buttons are pressed it results in characters sent by the
serial line to the motherboard. This is a nice feature that will make
the buttons on my old VCR box useful.
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Switches circuit board
Unfortunately I also had to cut off the circuit board with the switches
behind the buttons to make the VFD display fit. This makes the buttons
unusable, I suppose I will have to control the VCR with a remote instead.
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VFD on
The VFD looks really nice. It connects by a straight serial cable to the
motherboard. Once I got the serial cable right MythTV was able to control
the display. I thought that I could press connectors to a flat cable to
get a straight cable, but I had to modify the cable as the D-SUB
connector puts every second wire on the other row. At first LCDd caused
the display to flicker, but by changing a driver option from "vfd" to
"vkd" solved that problem.
A problem that goes away by itself usually also comes back by
itself. Once again the PCI bus has stopped working. I will have to buy
some USB DVB devices.
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USB devices
In an attempt to get rid of the PCI bus problems I bought two USB DVB-T
devices. On the PCI bus I have one DVB-T and one DVB-S card.
Unfortunately I wasn't able to find any good DVB-S device that would
be small enough for my VCR. I will try to keep the DVB-S card on the PCI
bus and hope that the PCI bus works better when it gets shorter and only
has one card. The PCI DVB-T card that now gets removed has been a very
nice card with a remote receiver on a cable and it also has analog video
inputs for S-video and composite using the good old and well known bt878
drivers.
I did some searches on the web to find USB devices with good drivers.
It seemed as if the Terratec Cinergy XS hybrid for both DVB-T and analog
video would be well supported. It also has a remote receiver on a cable
so I can place the receiver in the front behind the IR window.
The Freecom DVB-T which I also bought wasn't so easy to find information
about and exists in several different revisions. At least the Freecom
stick was rather cheap and if I will be able to use it MythTV will be
able to have picture in picture for DVB-T.
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Test of USB devices
None of the USB devices worked out of the box with my old kernel. The
latest stable drivers from linuxtv.org didn't compile with my kernel,
but the version before did compile. That version found the Freecom stick
but didn't find the Terracom stick. I used mercury to download the latest
development version of the DVB drivers and I was able to compile them and
the drivers found both my cards.
The drivers for terratec wasn't as good as I had hoped, but the
Freecom card seems to work better than I had hoped. The terratec drivers
seem to be unable to use analog inputs at the same time DVB-T is used. I
also wasn't able to get the remote working with lirc.
My quick test also gave me some more bad news... The distortions in the
picture is still there, they don't come from heat and the don't come
from the PCI bus. Right now I think the distortions come from a bad
antenna.
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Pinnacle serial remote
There is an old saying that trying to get bad hardware work fine with
Linux is a lot harder than buying good hardware that works fine with
Linux. I decided to ditch the Terratec remote that others have
reported works like an USB keyboard. Instead I got myself a Pinnacle
remote that connects to the serial port. That remote is supposed to work
fine with lirc and I will have no problems in the future if I decide to
to switch DVB devices.
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USB sticks below motherboard
I removed the PCI DVB-T card and have now instead placed the two USB
DVB-T sticks below the motherboard. Also the serial cable for the remote
receiver goes below the motherboard. With all this stuff there is no
longer any room for the fans so I had to remove them.
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A lot of removed stuff
The nice PCI DVB-T card had an analog input which probably could be
useful and it was connected to the scart connectors. Now I might just
as well remove those scart connectors and some cabling as well as part
of the PCI bus. All that space is now needed for other things.
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New connectors
The old scart connectors was replaced with new connectors only to fill
the holes, they are not connected to anything. Instead of the switch
which previously was used to select scart connector I have now added a
connector for stereo headphones. That connector might be useful for
debugging sound.
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Finished front
I have finally filled the last hole in the front. For this I used plastic
from the old opening for the VHS tape. If I am really lucky all the
hardware work might be finished by now. Still a lot of work remains. The
new remote must be configured and tested and the DVB devices must be
tested and configured in MythTV.
I was unable to get the USB DVB-T sticks working reliably. The PCI cards
seemed better, but I needed a new PCI bus.
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(Year 2008) |
New PCI bus
I got an old 1 GHz PIII
machine with a PCI bus and placed the cards in that machine.
Unfortunately I could no longer find the PCI brackets for the DVB cards
which I removed when I placed them in the VCR. I needed new brackets and
drilled a hole in a spare bracket and sacrificed an old network card with
holes in the right positions.
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PCI Brackets on place
The new PCI brackets did fit rather good. The 1 GHz PIII is running
mythbackend and my VCR PC is running mythfrontend. As the computers
are connected by ethernet the VCR is still able to use the DVB cards.
This backend/frontend design of MythTV is really nice.
Unfortunately I still have the distortions in the picture that I thought
came because of heat problems.
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Samsung LE40R87BD
I bought a 40 inch Samsung LCD TV to use as a monitor for my VCR. It has
a native resolution of 1360x768 at 60 Hz. Unfortunately I found that the
builtin unichrome graphics on the VIA mini-ITX card is unable to give any
higher resolution than 1024x768@60Hz. Trying to use a modeline for the
resolution 1360x768 gives an error message about not enough memory
bandwidth. Fortunately the image looks OK in 1024x768 resolution and
I really like this TV when it is working.
The TV also has a builtin DVT-T receiver and using this I could see
that the distortions I thought was because of heat problems also shows
up with this DVB-T receiver. Once I saw this it was easy to solve the
problem with an antenna amplifier.
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Problem with Samsung TV
Unfortunately there is one major problem with the nice Samsung LCD TV.
When the TV is powered on it says that there is no signal on the VGA
input. If the TV is powered on to watch the internal DVB-T receiver it
is able to display the VCR VGA input a few minutes later. This is very
annoying.
I have tried different combinations of monitors and PCs. The samsung
TV is able to without problem display VGA input from some PCs but not
all PCs that I have tested. The problem is not related to resolution,
refresh rate or polarity of sync signals, I have tried to tune the
modelines but it doesn't help.The PCs that doesn't work with Samsung work
fine with another monitor.
At first I thought this could be because of floating ground
voltage potentials. However, measuring showed that the ground potential
only differed 40-50 mV when the TV and VCR was disconnected and when
connected by the VGA cable the difference was only about 20 mV.
I borrowed an oscilloscope and looked at the sync signals of the VCR
(left) and two PCs which worked without problem. The VCR sync signals has
an amplitude of a little more than 3 V. One of the working PCs (right)
had amplitudes of about 5 V. Another working PC had amplitudes about 4 V.
It seems as if the Samsung monitor requires higher sync amplitudes than
my VCR gives. According to the specification the sync signals in the VGA
cable shall have TTL levels and anything above 2.4 V should be considered
high according to the TTL specification. To me it seems as if the Samsung
TV doesn't comply to the specifications.
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Sound
I returned the broken TV to Dustin and
got a new identical but working TV on warranty without having to pay for
the return shipping. Once the problem with the TV was solved I continued
the project by adding a receiver and speakers to get 5.1 sound.
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(Year 2009) |
More speakers
At first I only had enough speakers for 5.1 sound. However, I misplaced
the rear speakers for optimal sound. Instead of moving those rear
speakers to right behind my sofa I bought yet another pair of speakers so
I now have enough speakers for 7.1 sound. So far I haven't found anything
to watch with 7.1 sound, but the receiver still does a pretty good job
using all speakers when listening to mp3 files.
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Satellite dish
I almost regret connecting a satellite dish to the system. The first
thing that happened was that I got hundreds of channels inserted among
my previously carefully sorted list of channels. Trying to sort out and
categorize all these channels is a job which never seems to end. The dish
is aimed for Sirius, its position on my house makes it impossible to
aim for Astra. Most of the channels are really junk, so far I think
that I have been able to count to 3 channels which on rare circumstances
might have something worth watching.
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Final words
Once I had everything working it really is a fantastic system. MythTV is
a great piece of software. The only part of the system that could have
been a little better is the remote. The remote works fine for controlling
the VCR. Unfortunately also the remote for my TV and the remote for my
receiver also controls the VCR in accidental ways. Changing the
volume on the receiver with the remote often causes the VCR to start
navigating among its menus.
If I would build myself another such system I would buy myself some
kind of HTPC computer case. Most of my problems in this project has been
related to the lack of space in my current box. The project has taken
a few more years to finish than I first thought, but all those problems
has only been part of the fun.
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(Year 2010) |
Time for service
My refurbished VCR has now been working fine since May 2008, but suddenly it was
completely dead. It turned out that the PSU had some leaked capacitors.
Lately I have also had some problems with timeouts when my VCR tries to connect
to the mythtv backend PC.
The timeouts are caused by mysqld taking 100% CPU on the backend machine.
I tried to fix this by running myisamchk, but it didn't help.
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New smaller PSU
I replaced the broken PSU with a new smaller PSU. It is not only physically
smaller, unfortunately it is not as powerful. The old PSU was specified for 200W,
the new PSU is only 125W.
Being unable to fix mysql I instead did choose an easy fix;
adding yet another CPU to the backend PC. The motherboard with a single 1 GH
Pentium III was replaced with another old motherboard with dual 900 MHz Pentium
III CPUs.
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New PSU in place
I don't think this lack of power will be any problem as the PSU
no longer needs to give current to any DVB cards.
Even though mysql hogs down an entire CPU the backend PC is now responsive.
With both the backend PC and my VCR frontend upgraded I hope my system will
last for many years.
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(Year 2011) |
Time for BIG service
Again my video was dead. It turned out to once again be caused by leaking
capacitors, this time on the motherboard. I will have to replace the entire
motherboard.
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New motherboard
Today there are lots of interesting motherboards to choose from. Many of them
have fanless intel Atom CPUs. My old motherboard had two IDE channels and
I used them both having both HD and CDROM as IDE masters for best performance.
Now it is hard to find Mini-ITX boards with IDE channels. I finally found
a VIA board which at least has one IDE channel, I will rejumper the CDROM
to IDE slave.
It is a rather nice motherboard with a lot of serial ports and two
gigiabit ethernet ports. I will only use one ethernet port, but at least it
will be faster than my old motherboard which only had 100 Mb/s ethernet.
Unfortunately the serial ports on the motherboard have non standard
connectors with 2 mm distances instead of standard 2.5 mm distances. I will
need new serial cables to connect the remote and the VFD.
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Keyboard cable
The old motherboard used a special cable to connect ps/2 mouse and keyboard. I
used that cable to get a ps/2 keyboard connector to the back of my video. The
new motherboard doesn't have any such internal connector, instead I modified
the cable using a USB cable and a USB-ps/2 adapter to connect it to the back
panel of the motherboard.
The result with a brand new motherboard? First the good news:
- Quick network with 1 Gb/s speed
- The graphics chipset is capable of an image resolution of 1368x768 using
the VESA driver.
Then the bad news:
- The sound chipset is not recognized by Slackware ~10.2 from 2005, now
I have no sound.
- I have no working VFD in lack of cable and/or working serial port.
- I have no remote in lack of cable and/or working serial port.
- The old installed Unichrome driver does not recognize the new graphics
chipset. The VESA driver works, but video lags so much that it isn't
usable.
The back panel serial ports cannot be configured as ttyS0 or ttyS1
(com1 and com2 in MS-DOS). So far I haven't got any cables for the motherboard
serial connectors.
To get graphics working I downloaded a driver from VIA. Unfortunately that
driver was only for kernels 2.6.24 - 2.6.28. My old installation from 2005 has
kernel 2.6.12. I realize that I will have to do a total reinstall. According to
Distrowatch
Slackware version 12.1 and 12.2 might be usable with that driver, however I will
try latest Slackware 13.37, if I'm lucky the driver is included in newer kernels.
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