The vstcm is a vector signal transceiver PCB which generates colour vector graphics to be displayed on an oscilloscope or vector monitor such as Amplifone, Wells Gardner WG6100, Hantarex MTRV and Electrohome G05, as used in Star Wars, Tempest, Gravitar, etc.
When used with a computer (Raspberry Pi, PC, ...) running AdvanceMAME, it can be used to play classic colour (and monochrome) vector arcade games, but it can also play certain games all by itself using various emulators. If you search for vstcm on a well-known video sharing site you can see the board in action.
(Haven't got a vector monitor or an oscilloscope? Make your own, it's not that hard! - see below).
For those who built a V2 of this board, a document is provided to convert the wiring to run with V3 software.
The original v.st was designed by Trammell Hudson for black & white games. Documentation for that version can be found here https://github.com/osresearch/vst and here https://trmm.net/V.st/
Compared to the original version, the new vstcm adds:
- RGB colour with different intensity levels
- 6502, Z80 and 6809 emulators which allows it to play games on its own without a Raspberry Pi or MAME
- A mini version of MAME for playing vector games on the Teensy without a Raspberry Pi
- An upgrade to the Teensy 4.1 for more power (eg >800Mhz as opposed to 120Mhz for the Teensy 3.2)
- Asteroids style test patterns in Red, Green & Blue to aid CRT convergence
- A configuration menu with settings stored on the built in SD card
- Programmable onboard control buttons
- Programmable IR remote control buttons
- Extra pots to control X & Y position (to complement the existing X & Y size pots)
- Several power supply options: either USB, or external 5V/9V/12V
The board was built with simplicity in mind using components that are easy to find, and easy to solder so that anyone can build one.
Currently, the board can work in either of two ways:
- connected to a Raspberry Pi running MAME. The programme code for this option is a development of that which was provided with the original version of the v.st, with modifications made by "Swapfile" (Github user) to interface with AdvanceMAME, and then further modifications made by myself in order to add the new functionality specific to the vstcm, followed by extensive optimisation by fcawth (cf his fork of this project). There is scope for further improvement (see the wiki for this project in the link above), and it is hoped that the publication on github will encourage contributions to develop this as a relatively cheap and easy solution for the vector arcade / vector graphics community.
- on its own, running a 6502, Z80 or 6809 emulator, and with the original game ROM files stored on the SD card of the Teensy. So far, Battlezone, Asteroids and Donkey Kong work with this, but it shouldn't be too much trouble to get others working. Sound and external controls have not been properly implemented as yet (please feel free to contribute the necessary mods to the code...). See instructions below for how to get this to work.
For those interested in seeing how things got to this point, the inital development of the PCB was documented with plenty of pictures (in French, but use Google Translate if required) here : https://www.gamoover.net/Forums/index.php?topic=43469.0 (from page 5) and also shows previous work on building vector arcade HV boards, an Amplifone deflection reproduction, an Asteroids game PCB reproduction, a bit of yoke rewinding, etc.
If you want to get in touch to ask questions, or contribute, I can be contacted at: robin@robinchampion.com or on Github (user english1234), Gamoover (english2), UKVAC (english2), KLOV (english2), as well as via the various vector graphics/Vectrex forums on Facebook.
A dedicated vstcm web page can be found here: https://robinchampion.com/vst_colour_mod.htm
Thread on KLOV: https://forums.arcade-museum.com/threads/announcing-the-vstcm-colour-vector-generator.505940/
Thread on UKVAC: http://www.ukvac.com/forum/announcing-the-vstcm-colour-vector-generator_topic388998_page1.html
A ZIP file is in the Gerbers directory. This can be uploaded to your PCB manufacturer of choice. It's a 2 sided 10cm x 10cm board so should be extremely cheap (JLPCB charged less than 5€ / $5 + shipping for 10 pieces in May 2022).
The BOM is in a dedicated folder and has Mouser references for many parts at the right hand side.
- IC2: You need to choose if you are going to use an external supply or not and if so what voltage to use (5V, 9V or 12V). Recom makes these parts, but so do Traco and there may be other brands. Make sure there is a D (for double) at the end of the model number which generates +/- voltages, rather than the S (single) version. See power options below.
- The Molex parts are not strictly necessary, you may prefer something different or simply to solder wires directly to the holes in the PCB.
- U5: See power options below. I have also used a 7805 as a direct replacement with a small heatsink on it, which gets quite warm but hasn't burnt out as yet.
- optional IR remote: I really recommend this if you are putting the board inside a cabinet - see "IR remote programmable control buttons" below.
I would recommend socketing everything on the board (Teensy, DACs, Op Amps) so that they can be swapped out if better choices are found in the future.
Make sure you order short resistors, space for them on the board is tight.
The PCB can be powered in several ways:
| N° | Power supply option | Supplies | C3/C4 | IC2 | U5/C19/C20 | Split pad Teensy | Tested |
|---|---|---|---|---|---|---|---|
| 1 | USB 5V | Complete circuit inc Teensy | Required | RB-0512D | Absent | No | No |
| 2 | USB 5V + external 5V unregulated | USB supplies Teensy, external supplies rest | Required | RB-0512D | Absent | No | Yes |
| 3 | External 9V unregulated | Complete circuit inc Teensy | Required | RB-0912D | Present | Yes | No |
| 4 | External 12V unregulated | Complete circuit inc Teensy | Required | RB-1212D | Present | Yes | Yes |
| 5 | USB 5V + external 12V regulated | USB supplies Teensy, external supplies rest | Absent | Absent | Absent | No | Yes |
1/ power the whole thing via USB from a Raspberry Pi: This requires a short good quality USB cable to work reliably. Make sure the Pi has at least a 3A supply.
2/ power the Teensy via USB from a Raspberry Pi, and use a separate external supply (such as a wall wart) for the DACs and Op Amps.
3 & 4/ power the whole thing via an external supply which can be 9V or 12V (not 5V): this requires adding a LM2940T-5.0 regulator at U5 along with it's associated caps at C19 & C20, as well as cutting a link on the Teensy to ensure that it doesn't receive conflicting power from both the USB and the external supply. The RB-xx12D needs to be either a 9V or 12V model depending on the voltage of the external supply. A 5V supply won't work as the LM2940 requires over 6V to function according to its datasheet.
5/ If you already have a perfectly regulated and smooth 12V supply, then you can connect it to J7.
The choice is really just a matter of what you have on hand. It makes no difference what vector CRT you have, as the output voltages of the PCB are the same whatever you use to power it. If you're connecting to an existing arcade machine, then chances are you have a +/-12V supply coming out of the power brick. Otherwise, many people have a box of old "wall wart" 5V (or 9V or 12V) adapters which will work fine: either fit a barrel connector to the PCB input or chop the connector off the end of the power supply and solder the 2 wires directly to the board (check with a multimeter first which is positive and which is ground).
The easiest option is to use a 5V (option 2) as the LM2940 is not required, and you don't need to cut the link on the Teensy to separate USB and external power.
This may seem obvious, but it's worth downloading Kicad in order to view the schematic and the PCB as there are some build notes on the schematic, and it will help you to understand the main sections of the PCB and how it all connects together. For the lazier, a PDF is available.
Follow the instructions on this page to download and install the Arduino environment and Teensyduino extension: https://www.pjrc.com/teensy/td_download.html Use the Arduino software to load the .ino file in the Teensy code directory.
Connect the Teensy via USB to your computer.
Choose the Teensy 4.1 in the Teensyduino options, and overclock to 816Mhz, as well as the "Fastest" option. Make sure you have the latest version of Teensyduino.
Press the compile button. You may need to add the Bounce2 library if you don't already have it.
Press the upload button (or the button on the Teensy if it doesn't upload automatically).
(You can also use PlatformIO if you prefer).
There is a more detailed guide "How to programme the Teensy with the code for the VSTCM PCB.pdf" in the root directory.
Once the board is built and the Teensy programmed and fitted, it can be connected to your deflection board of choice (it has been tested on Amplifone, Wells Gardner WG6100, Electrohome G05 and Hantarex MTRV so far) and when powered on should show a test screen. It may be necessary to change the size and positions pots on the PCB as well as other controls on the deflection board (such as Z or colour gain).
Before connecting to the deflection board, it would probably be a good idea to make sure the vstcm is generating appropriate voltages at its outputs (preferably with an oscilloscope, or failing that with a decent multimeter).
If you want to save changes to settings shown on the onscreen menu, then put a SD card in the Teensy, and put the vstcm.ini file in the root directory.
Put the following ROM files on a SD card in a directory called roms/Battlezone: 036414a.01, 036413.01, 036412.01, 036411.01, 036410.01, 036409.01, 036422.01, 036421.01 (it's up to you to find them from somewhere...).
Put the SD card in the slot on the Teensy.
Upload the bzone.ino to the vstcm using the Arduino software.
Plug it in.
Switch on!
If you have a IR remote then you can control the game in a rather basic manner for the moment... (press OK to start)
A Raspberry Pi 4 or 400 is recommended (I have also tested with a Pi 3 Model B+ 2017 and an Orange Pi 3 LTS which seem to work ok too). If you are running the vstcm from the Raspberry/Orange Pi then a 3A supply would be preferable. Other options (which I have not yet tested) are PC (either Windows or a Linux VM under Windows, or native Linux) or Mac. I followed the instructions here to download and compile AdvanceMAME: https://www.arcade-projects.com/threads/almost-pixel-perfect-arcade-emulation-on-raspberry-pi-with-advancemame.7777/
Basically, there are just 7 commands on the Pi which are as follows:
git clone https://github.com/amadvance/advancemame.git
cd advancemame
sh autogen.sh
./configure
make -j3
sudo make install
You need to find some ROMs from somewhere and copy them into the ROM folder. I'm sure you'll manage to find them... The easiest way to get them on to the Pi is to set up a Samba share and copy them over from a PC.
Then to launch, type advmame followed by the name of the game.
If you're not getting output over the USB cable to the vstcm, then check the advmame.rc file and at the bottom make sure you have vector_aux_renderer set to dvg (instead of none) and vector_aux_renderer_port set to /dev/ttyACM0
The AdvanceMAME protocol for the USB DVG is here: https://github.com/amadvance/advancemame/blob/master/advance/osd/dvg.c
For £1 / $1 / 1€ you can get a HX1838 infra red adapter board with remote control, wiring, everything you need in fact. There are only 3 wires to connect: 5V, GND and signal. I soldered pin headers in the holes provided on either side of the Teensy, and put 5V on the bottom left hand hole of the Teensy (to left of USB socket), GND on the bottom right pin of the Teensy, and signal on pin 32 (top right hand pin of Teensy).
This might seem like a bit of a gadget, but when you are spending your time going behind the arcade cab to press a button, coming back round the front to see the effect on the screen, and doing this over and over again, the advantages become obvious!
The IR sensor is the size of an LED and so very easy to hide somewhere at the front of an arcade cab, and then you can just change the settings at will while you look at the screen.
Apart from this PCB, you need a CRT, a high voltage board, a deflection board and a power supply to make a complete vector monitor. There are solutions for all of these parts:
CRT - I'm using a 19"/48cm Philips TV bought for pennies through the small ads. You need to rewind the yoke using magnet wire. There is an excellent video by Jason Kopp here which explains all: https://youtu.be/Ci9qiGVMF7s I experimented on a 5" b&w security monitor first, then went for the big screen. Avoid Trinitrons and PC monitors, you need a basic no frills TV tube. It took me several attempts to get it more or less right, but I still have some wires which are not completely straight and the result seems to be the slightly bent vectors visible in the top right hand corner of my screen in the photo of the test screen above. The whole thing really wasn't hard, it just requires patience.
High voltage: Amplifone and Wells Gardner 6100 blank PCBs are available online, and there are also fully built solutions (see the various vector groups on Facebook) available new or second hand from the usual auction sites and specialist arcade sellers (mostly USA based).
Deflection board: I bought a second hand non working Amplifone and then fixed it (which wasn't hard, plenty of info online), but new PCBs are available online, and a Wells Gardner WG6100 should work too.
Power supply: the CRT and deflection board can be run either from an old Atari power brick, or else by wiring together two cheap 24V power supplies from Aliexpress in order to provide +/- 24V which satisfies the requirement for 50VAC on a Amplifone colour vector monitor. The CRT needs 6.3V for the heater filament, which I'm getting from an Atari power brick using the supply meant for the coin door, but there are other solutions if you look online (hint: 6.3V is frequently required for valve amp projects). If you find the right Atari power brick, it will power the whole thing: CRT, HV, deflection, Raspberry Pi and vstcm.
There's plenty of discussion of solutions to these problems on KLOV, UKVAC, and the FB vector forums with plenty of knowledgeable people able to answer questions. Also there are a fair few videos on Youtube going from theory to practice. Again, it's not that hard, so give it a go!