Tag: monitor

  • Very Good At VGA

    Recently, [Justin] asked: Can his beautiful Tektronix 606 XY monitor be made to work as a computer display?

    And even more recently, [TJ] explained he has a plethora of Tektronix devices, and asked how he might put them to use…

    So lovely… but what can you DO with it?

    Well, “putting to use” is precisely what we do here at Oscilloclock! And one option, indeed, is to hook the target device up to a modern-day PC and use it as a computer monitor.

    Time for an update on the Oscilloclock VGA Core and its variants!

    Shades of Grey Green

    Avid readers may recall these previous posts about making SVGA and XVGA displays from vintage oscilloscope CRTs:

    VGA display… On a 3″ scope tube!
    The VGA Cube!
    New Year’s Resolution!

    Truly dedicated readers may even recall that the solutions presented drive the CRT directly, completely bypassing any internal circuitry of the host device. And, that there were limitations in the current design; the most serious being binary blanking, where the beam is switched either on or off. There were no shades of grey.

    This Running Man needs no shades!

    Inspired by [Justin], we experimented connecting the Oscilloclock VGA Bare (a barebones VGA interface board) to our lab’s Tektronix 620 XY monitor. This bad boy has an analog Z axis (intensity) input, meaning that we can theoretically have shades of grey… er, green.

    And the result? A pretty decent PC display!

    A recent post, as displayed on the Tektronix 620. (Yes – I know it’s upside down)
    Here’s what it looked like on the laptop’s display

    Doomy Demo

    Ever wanted to play classic Doom on an old green screen? Here we go!

    This Tek 620 is no longer doomed – it’s been Doomed!

    Yes – the display is horizontally inverted. The VGA Bare currently does not support flipping the X and Y signals.

    This unintended challenge makes playing Doom exceptionally difficult!

    Matrix Masterpiece

    Who could resist displaying digital rain (Matrix code) on an old Tek display?

    Matrix code, as generated by tmatrix. Note it’s horizontally inverted

    While working on this demo, I learned more about Matrix code – and that it includes Japanese characters scanned from the creator’s wife’s cookbook. Wow, I thought those raindrops looked awfully familiar!

    The Setup

    Not a bad result! And the hardware setup was simple.

    • PC
    • HDMI to VGA adapter cable
    • Oscilloclock VGA Bare
    • BNC cables and connectors
    • A few resistors
    • Power pack

    As always, nothing is perfect! A few tricks were needed to make the experiment a success:

    1. The VGA Bare circuit needed a few minor improvements, to better support official SVGA and XVGA timing standards
    2. A crude level adjuster (resistive divider network) was needed between the analog intensity output and the Tek’s Z axis input
    3. The PC display resolution needed to be set to SVGA (800 x 600) or XVGA (1024 x 768), to give maximum clarity
    4. A high-contrast theme was selected, to greatly improve display contrast

    What’s next?

    With the successful close of this proof-of-concept, [Justin] and [TJ] now have another clear option to make use of their vintage test equipment: a VGA Bare ready to mount inside their device, or a beautifully encased VGA Connect (à la Oscilloclock Connect).

    But to make this truly production-worthy, a few improvements are needed:

    1. Output voltage level adjustments, fully independent for X, Y, Z
    2. A higher-voltage Z amplifier
    3. Independently invertable X and Y signals
    4. Reduction in the ‘ghosting’ or ‘ringing’ effects currently observed
    5. Improved contrast and avoidance of ‘washout’ seen between pixels
    6. Digital HDMI input !

    … all added to Oscilloclock’s ever-growing backlog of things to do!


    Do you want to play your favourite classic game on your old XY monitor? Do you want to stack 10 oscilloscopes on your shelf and have them all showing Matrix code? Or put your Grandpa’s old scope on your desk at work and have it display your Outlook calendar?

    Our mantra makes it possible: Just. Because. We. Can.

  • VGA display… On a 3″ scope tube!

    Yes, you’ve all thrown away your lunky old CRT monitors, in favour of sleek ultra-thin LCD displays. And, you thought you’d never see another one again…

    But this CRT display has a twist! It’s round. It’s small at just 3 inches diameter. And it’s awfully cute.

    Oscilloclock 3-inch CRT VGA Display Assembly - overview

    Last year, I was approached by a dedicated flight simulation enthusiast, who needed a radar indicator to use in a fighter cockpit replica. The indicator should employ a CRT, for the most realistic look. Could Oscilloclock design and construct such a display?

    It didn’t take much convincing! Diverging only temporarily from building clocks, I took up the challenge to create my first raster-scan CRT display unit. In the ensuing months, difficulties sprang forth from every direction in the project, but ultimately I was able to avoid a diraster (sic) and deliver a functional assembly:

    See more related videos on my YouTube channel

    The Setup

    The key component of this setup is a new prototype VGA Board that converts a VGA signal into analogue X and Y outputs. Both analogue intensity and binary blanking outputs are provided.

    Oscilloclock VGA Board prototype
    Oscilloclock VGA Board prototype

    The X and Y outputs drive an Oscilloclock Deflection Board, while the binary blanking output drives the blanking amplifier in a CRT Board. Blanking isolation, heater, and HV supplies are provided by a Power Board.

    Oscilloclock Deflection Board - modified for ultra-linear HV output
    Deflection Board – modified for ultra-linear HV output
    CRT Board - heavily modified for improved frequency response
    CRT Board – modified for improved frequency response
    Power Board - with improved optocoupler
    Power Board – with improved optocoupler

    It all looks so easy! But noooo. Astute readers will recall from other posts that every Oscilloclock project involves sleepless slumbers, horrific hair-pulling, and forgotten family members. Let’s see what caused me grief this time…

    (more…)