Showing posts with label Vectrex. Show all posts
Showing posts with label Vectrex. Show all posts

Saturday, 20 October 2018

Vectrex & LZX video synth - Curliing effects

I was trying to achieve vector rescanning on the vectrex but instead got some rather
interesting  though unexpected "curling" effects.

Has anyone does something similar ?

some pics of the LZX setup.

tHE image on the vectrex was really small initially, but with amplification i was able to fill about 2/3 of the screen

I connected a horizontal ramp to the X input, a vertical ramp to Y and the composite output to the Z. 
Maybe I should use a luma output ?
 
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LZX - Cadet IV - Ramp generator

This is the fourth module in the series of LZX's Cadet DIY synthesizer.
Many thanks to Liz for making this possible.
A ramp generator is a signal generator which generates a ramp waveform.

It's actually a dual ramp generator which "creates 3 different fixed frequency ramp waveforms locked to the horizontal and vertical dimensions of a video display".
That 14 pin input header in the pic below is where the horizontal & vertical sync signals enter the module.
Modules with 14-Pin Sync Outputs include Visual Cortex, Video Sync Generator and Cadet I Sync Generator.

This will be essential if I want to do some vector rescanning.


The LM6172 op amp
This is used a lot in the cadet series. Get lots of these !!!

 The TL431 - buy this in bulk too.



ICs (and other impt components) used in this build:
LM6172IN/NOPB  (x2) ...this is a dual op amp... specified at ±5V power supply for low
                                 voltage applications such as portable video systems.
TL431BQLPR (x3).... Adjustable Precision Shunt Regulator
                               TL431 shunt regulator circuit explained 
TL072IP - standard op amp
SN74HC14N- - it's a hex schmitt trigger
TL074CN (x2) .....standard op amp
BS170 N-Channel...MOSFET...metal-oxide semiconductor field-effect transistor.
           used for switching or amplifying signals.


The SN74HC14n .... its also used in the Cadet IX VCO  though I don't think its responsible for the waveform generation in this circuit (please correct me if I'm wrong).

I think the ramp generators are built using mostly transistors.(2N3906/BS170)
For this to work, the voltage must be very precise... thus the use of the TL431.
This waveform increases steadly as the capacitor charges until it hits its peak and then decreases suddenly as the capacitor discharges.
Since this waveform repeats over and over again, this waveform generator appears as an oscillator.

iT'S DONE !!!
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Links:
LZX official
Muffs - Cadet series DIY/assembled
All about ramp generators
Youtube  Ramp Generator Circuit built with Transistors

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Friday, 19 October 2018

Rutt-Etra - Vector Rescanning - the perfect monitor?

A bit about vector rescanning 

I've been trying to accomplish vector rescanning for years.
Never really successfully.
Part of the problem I think has been my early confusion & lack of understanding of the different types of oscilloscopes, vectorscopes & waveform monitors (and I'm still learning).

Living in Australia, doesn't make it easier to find old working scopes from the 70's and 80's and attempts of posting them from the USA usually ends in tears. Postmen seem to love throwing delicate analog instruments around in their truck. I lost 3 scopes this way.
Two that have survived the rigours of FedEx & Australia post are the Tektronix T922 and 465B
Lovely scopes that I use all the time for standard audio waveform measurements .... but not 100% successful for Rutt-Etra stuff.

 Tektronix T922
 Tektronix T922 rear with z axis input.

 Tektronix 465B

The two models that often come up in the various forums as working well for vector rescanning are the
Leader LBO 51MAC, and the Tektronix 620 .
(Unconfirmed ... Leader LBO-514A & Tektronix 608)
Leader LBO-51MA

Tektronix 620 is on the left.
I just purchased this on ebay. It hasn't arrived yet, & I'm waiting with anticipation to see if it survives the trip.

And of course, there is the vectrex.

My understanding is that the vectrex isn't prefect for vector rescanning as it does not have the bandwidth ....but it kinda works in limited ways
It is better suited for lower frequency oscillographics.  

However, if you still want to do vector rescanning you need:
1.Video Input to extract luma from your video source
2. H & V ramps generator .

Thus if you are using Cadet modules you only need one Ramps, a Sync Gen and an Input. 
A LZX visual cortex (VC) has all of this.
Connect the horizontal ramp to the X, the vertical ramp to Y and the luma output (of the VC or the VideoInput) to the Z. 



The Rutt/Etra Video Synthesizer is an analog raster manipulation device built in 1972 for image processing and real-time animation. The Rutt/Etra was co-invented by Steve Rutt and Bill Etra

 
Links
+ Muffs- vector modification
+ Vectrex Hackaday
+ Hacking a vectrex - Lumpybanger
+ Zektor - using the vectrex monitor
+ Muffs - vector rescanning for dummies
+ Muffs - good oscilloscope for vector rescanning
+ Rutt-cadetra blog 
+ Rutt/Etra Video Synthesizer Demo (1974) youtube
+ Rutt-Etra-izer

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Tuesday, 16 October 2018

Vectrex - hack

Found a second Vectrex. :-)
I have two now, one to play and the second to use  for vector rescanning.
This has come all the way from France.


As a retro gaming collector, it hurts to modify this. So I'll try to make as few changes as possible.

Time to open her up.
Be very very careful of the tube. Even after not being powered for weeks they can still retain lethal voltages. So discharge it first.

I used this screwdriver (place under the protective rubber CRT cap) which I attached to ground via the alligator clip. Listen for the pop !
I can't stress enough the risk of discharging the tube. If you are not sure what to do , get a qualified technician. These voltages can kill.

Some pics .. this is the CPU section




In the pic below, the CPU section is on the base, and the XYZ driver board is positioned vertically. It is to the left of the tube.
The CPU is connected to the XYZ driver board in the un-modified vectrex
The CPU is what creates the images.


 In the pics below, the XYZ board lies behind the heatsink.

You need to separate these two boards. and wire the XYZ inputs to the back.
I'll use 3.5mm jacks.

Another view of the CPU board. The Red, Blue & Yellow connector is the XYZ connector.
Unplug this.

Rather than cut the female XYZ connector ive decided to use a header to make a new male connector 
 
It may look confusing, that I have 6 jacks .
3 connect to the CPU, and 3 connect to the XYZ driver board.

The pic below is the inside of the case. First, connect all the grounds. 
 


In modifying the vectrex, what I am doing is finding a way to replace the CPU's control voltages with control voltages from a modular synthesizer.
 
So most people just cut the 3 leads leading to the XYZ driver board and connect that to the modular synth.
This is fine , however, the CPU is now useless... and you can no longer play games, unless you reopen the vectrex and reconnect everything.
 

Below is the outside of the case.

All I have done is bring the 3 wires that connect to the CPU , to the back of the machine and attached 3.5mm jacks. (The ones on the left)
 
I have also brought the 3 wires that connect to the driver board , to the back of the machine. and attached 3.5mm jacks. (The ones on the right)
 
So if I wish to connect a modular synth, use the 3 jacks on the right (DONT connect to the left).
 
The (3 right) X,Y,Z inputs are CV inputs to the driver board.
I understand that 0V (on both X and Y) its the centre and that
±9V works on the on the horizontal X input and ±11V on the vertical Y input.
... to be tested.
 tHE green wire is ground.

The inside of the jacks


Connect like this to return the Vectrex to normal so you can play games again
I could instead add a switch, though this would involve more holes & drilling.
I've attempted to keep any destruction of this vectrex to a minimum.
So the only permanent modification was drilling the 6 holes for the 3.5mm jacks. All the original wiring is preserved!!! So you can re-connect the wiring for gaming action!

Now that you've modded it what standard eurorack audio modules should you use??
In my test I used:

The elby matrix mixer is a real winner. The bluelantern Thruzero VCO & the steiner microVCO also worked nicely.
Other possible modules:
+ Synovatron CV tools, DPO, MATHS, Wogglebug.
"Maths is usually the Z input, I'm mainly just playing with the speed of the pulse - as if it's a really fast envelope.
Then two or more outs from both oscillators in the DPO are going to X & Y,..."

+ e340 for X & Y. -- cloud generator
+ Thonk/Fonitronik Cascade 
+ If you have a ARP 2600 or a TTSH, the voltage processor is excellent for modifying the 3 input signals 
+ Pip Slope and an O/A/x2 from ALM / Busy Circuits
+ PDO and Akemie's Castle 
+ Clouds  
+ 4MS Shifting Inverting Signal Mingler  

A bit about vector rescanning

My understanding is that the vectrex isn't prefect for vector rescanning as it does not have the bandwidth ....but it kinda works in limited ways
It is better suited for lower frequency oscillographics.  

However, if you still want to do vector rescanning you need:
1.Video Input to extract luma from your video source
2. H & V ramps generator .

Thus if you are using Cadet modules you only need one Ramps, a Sync Gen and an Input. 
A LZX visual cortex (VC) has all of this.
Connect the horizontal ramp to the X, the vertical ramp to Y and the luma output (of the VC or the VideoInput) to the Z.
 

Links
+ Muffs- vector modification
+ Vectrex Hackaday
+ Hacking a vectrex - Lumpybanger
+ Zektor - using the vectrex monitor
+ Muffs - vector rescanning for dummies
+ Muffs - good oscilloscope for vector rescanning
+ Rutt-cadetra blog

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Click here to access the Video Index page

Friday, 14 September 2018

Vectrex - Game

New Toy !
This dates from 1982.




A post shared by jono (@dj_jondent) on
Vectrex was the first company to bring vector graphics to the home audience via a vector monitor.
This was a time when most arcade games used vector graphics. (for instance in Asteroids and Space War), different from the raster technique used in most home video games that connected to televisions. Vector graphics are essentially lines of light. Raster graphics consist of small pixels or blocks.

The built in game, Minestorm is a derivative of Asteriods.

I remember playing asteriods on an Atari back in those days and the vectrex is probably the closest thing I'll get to experience this today, short of buying a vintage arcade machine.
This video is a very cool... recreating asteiods with lasers:
https://www.youtube.com/watch?v=FkHjG759ABY


So I'm lucky to have found a working vectrex.
Considering if I should mod it or leave it alone.
Will probably mod it.
I'm interested in using the monitor for video synthesis.

One peripherial I don't have is the light pen.
There are however a few sites with hacks for making my own.
 http://www.playvectrex.com/vectech/mvlp/mvlp_f.htm
and:
https://www.youtube.com/watch?v=6On2AFPx6pc

The working end of the pen is a cheap silicon L14G3 phototransistor


The other periphery are the 3D glasses.
...so so rare. This 3D system predated the Sega Master System's SegaScope 3D by about four years.

The monitor is Black & white.
Every game came with its own coloured and transparent overlay, that could be attached to the screen.

Specs:
Manufacturer:  Western Technologies/Smith Engineering which was a videogame company started by  Jay Smith, an engineer who was previously an employee at Mattel. It was licensed and distributed first by General Consumer Electric (GCE), and then by Milton Bradley Company after their purchase of GCE.
The Vectrex was known as Bandai Vectrex Kousokusen in Japan.

Release year: 1982
Discontinued :1984


MPU: Motorola 68A09 (MPU= Microprocessor)

It's a DIP-40 8-BIT MICROPROCESSING UNIT.
On the actual PCB it's IC206.

Frequency The MPU operates at 1.6 MHz from a 6 MHz external Xtal. 
                   An internal divide by 4 circuit generates the MPU 1.6 MHz "E" clock signal 
                   used in the system

ROM: 8KB  (one 8-bit 2363 chip) ,  4KB used by Minestorm.
          On the actual pcb the ROM chip is IC201. It's the sharp 284001-1

RAM: 2 x 1KB (two 4-bit 2114 chips). These RAMS provide storage locations for data
         indicative of locations of objects, game status, and various other information 
         needed by the microprocessor during game operation. (IC 204 & 205)

Sound: 3 channels through a General Instrument AY-3-8912 sound chip
            You will find this chip on the Logic board. It's IC 208.
            3" electrodynamic paper cone speaker.
            3 voices (all square wave). 1 noise generator

Media:  ROM cartridges 32KB

Display : 9 x 11 inch CRT (240mm diagonal), Black & White monitor. Samsung model 240RB40
              Resolution: 330 × 410


WEIGHT: 15 Lbs.

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The standard TTL device types 74LS00 and 74LS32 are used as control line decoders to allow the MPU to select the appropriate circuit element to be addressed at any particular time.
The 74LS32 decodes logic to perform read and write access to the RAM by the processor . The 74LS32 is a Quad-ORgate. (IC203). Its obsolete so you have have trouble finding replacements.
The 74LS00 is a 2/IN NAND gate. (IC202) .


**Any TTL chips you find with the code 74LSxx are Low power Schottky and date pre 1985.
They were superceeded by chips using the code  74ASxx - Advanced Schottky.
TTL stands for Transistor–transistor logic. Its a logic family built from bipolar junction transistors. Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor")**

The analog processing section includes digital to analog converter (DAC) chip type MC1408, dual 4 channel multiplexer/demultiplexer chip type CD4052, and dual channel op-amps types LF353 and LF347.

The DAC chip 
(Digital to Analogue Converter) MC1408 receives an 8 bit word at data terminals D0-D7. DAC output (pin 4) is current source. This IC is responsible for graphic output
 
One section of IC LF353 is used to change this current to a voltage representative of the 8 bit digital word received by the DAC chip. The LF353 voltage is applied to an input of the dual 4 channel CMOS multiplexer (MUX) chip CD4052. This same voltage (designated "DAC" on the schematic) is the X-axis drive signal. 

The CD4052 MUX chip serves two purposes: it selectively couples, under MPU control, the output of the DAC current/voltage converter to one of 4 places and is used to selectively couple the inputs from the joystick pots to the voltage comparator IC LF353.

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If you are having any problems with the joystick interface try replacing the AY-3-8912 sound chip.
You would think that the 6522 Versatile Interface Adapter (VIA) is the obvious choice for the joystick interface, but  it turns out to be connected to the General Instrument AY-3-8912 which also has an 8 bit IO port. 

(The above information is from the Vectrex technicial manual).