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Mac Sync-inator VGA Sync Converter Launches Today!


Today I’m very excited to officially announce a new addition to the BMOW product lineup: the Mac Sync-inator VGA sync converter. I’ve been talking about this project for months, and it’s been available in small quantities while I gathered customer feedback, but now it’s finally ready for the bright lights and prime time. If you own a classic Macintosh or Apple IIgs computer, and have ever struggled to get it working with a standard VGA monitor, then the Mac Sync-inator is for you.

The Sync-inator is an adapter for connecting Apple video sources (DB-15) to VGA monitors (HD-15), with active sync processing circuitry that sets it apart from typical passive video adapters. There’s a built-in microcontroller that analyzes the incoming sync signals in real-time, automatically selects the best adapter settings, and can optionally reprocess the sync signals into a different format for better compatibility with some VGA monitors. You can even view a debug log of diagnostic and technical information about the video signal, as seen by the Sync-inator. For video format nerds as well as for people who want something that “just works” with minimum hassles, there’s a lot to be excited about here.

Sync-inator Benefits

  • Three different sync processing modes, for wider compatibility than other VGA adapters
  • Automatic sync mode selection, for easy setup
  • Sync activity LEDs for quick troubleshooting feedback
  • Serial port output of video signal diagnostic info
  • Plus all the other capabilities of standard VGA adapters

What is this and why should I care?

In short, the Sync-inator makes it possible to use many types of VGA monitors that previously wouldn’t work with your classic Apple video source due to sync compatibility issues. It also removes much of the frustration that’s typically associated with using passive DIP switch VGA adapters, by using a microcontroller to automatically configure some of the adapter settings. It will do everything that common passive Mac-to-VGA adapters will do, plus more. If you’ve got a monitor that stubbornly refuses to work with your vintage Mac video card, give the Sync-inator a try.

Sync-inator is not a video scaler, and it doesn’t modify the video resolution or colors in the RGB video signal. Only the sync signals are affected.

What the heck is sync?

The video signal from your computer or video card contains synchronization information which helps your monitor detect the beginning of each new line and new frame. There are several different ways in which this sync information can be encoded. Some computers only support specific sync methods, and some VGA monitors can only handle specific sync methods. If your monitor can’t handle the sync signals from your computer or video card, then you’ll have a problem, even if the monitor supports the video resolution and frame rate.

In the world of classic Apple computers, the two most common sync methods are composite sync and separate sync. With composite sync, the horizontal and vertical sync information is combined into a single output signal. With separate sync, horizontal and vertical information is transmitted with two distinct sync signals. Some computers can only output composite sync, or can only output separate sync. Some computers output one or the other at different times, depending on which specific video resolution is active. Some computers output both composite sync and separate sync simultaneously.

The Sync-inator is able to convert a composite sync signal into separate horizontal/vertical sync signals, using several different methods. It’s also able to analyze the incoming sync signal and make an educated guess about which conversion method is best, although this choice can be overridden if you prefer a different method.

What’s wrong with my computer? Is it even working?

The Sync-inator also has two built-in LEDs for debugging and troubleshooting video problems. If your monitor remains dark and no image appears, the LEDs can provide information to determine if the problem is with the monitor, the computer, the choice of video resolution, or something else. One LED will light whenever a composite sync signal is present, and the other LED will light whenever a separate sync signal is present. If neither LED is lit, then your computer isn’t outputting any video, and you’ll need to troubleshoot the source. If one or more LEDs are lit, but the monitor doesn’t show any image, then you’re likely dealing with some kind of unsupported video mode and will need to troubleshoot the monitor itself.

Debug Log

The Mac Sync-inator has a serial port where debug logging information is provided. The debug log is an optional feature, and all the Sync-inator’s capabilities can be used without ever looking at the log. But advanced tech nerds may find the log info interesting. To view the log, you can attach a USB serial cable to the TXD and GND terminals at the edge of the Sync-inator PCB, and set your terminal software’s serial port speed to 57600 bps. The debug log lists the current sync processing mode, including the result of the automatic processing mode’s analysis, as well as the period and frequency of the detected sync signals and other technical information. Here’s an example showing an Apple “Toby” NuBus video card running at 640×480 @ 67 Hz resolution.

* BMOW VGA Mac Sync-inator, v 1.0
sync mode: choose automatically
detecting sync signals...
hsync no
vsync no
csync yes
csync horiz period 28.5 us, freq 35.0 kHz
csync vert period 15.0 ms, freq 66.3 Hz
auto-select: convert csync into hsync and vsync
csync: pulse width 9 20 871, period 142 285 1003

Get your Sync-inator Now

For details on the Sync-inator, usage instructions, or to make a purchase, please see the main Sync-inator page at the BMOW web site. I hope this new device will be as useful for you as it has been for me!

Read 2 comments and join the conversation 

2 Comments so far

  1. John Payson - April 18th, 2024 7:22 am

    Never underestimate the power of blinkenlights. It’s amazing how often what seems like a major problem can be instantly revealed to be something simple as a result of a well-placed blinkenlight.

  2. Marc Gorelick - April 22nd, 2024 8:24 pm

    A few months ago I bought a dead IIci. Once I solved the power supply problem, it would boot but I could not find a way to get a working display. The monitor that I got with the machine was also dead and none of the video converters I’d tried would produce an image on a VGA monitor—until the Sync-inator. I’m a happy BMOW Floppy Emu customer and the description of this product seemed like it would exactly solve my IIci video problems, so I figured I’d give it a chance…and it did! I got a working VGA image from my IIci the moment I hooked it up. Very happy customer.

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