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Seeking beta testers for Mac Sync-inator VGA sync converter


Well-known member
The BMOW Mac Sync-inator is finally ready for public consumption, and I'm looking for 3-4 beta testers. The hardware is free for testers, in exchange for you taking the time to put it through the wringer with your vintage Mac or Apple IIgs systems and video cards and monitors, and send me detailed notes on what you find. Testers with particularly old or weird computers, video cards, and monitors will have top priority but everyone's welcome.

If you missed the earlier discussions about the Sync-inator, it's a Mac-to-VGA video converter with a sync processor built-in. More than just a passive adapter, the Sync-inator will analyze the sync signals received from your computer and decide how to convert them if necessary, enabling better compatibility across the spectrum of vintage video source and monitor combinations. It’s especially valuable for video sources using composite sync, such as the Macintosh IIci and IIsi, the Apple “Toby” NuBus card, and many early third-party video cards. It's compatible with all classic Macs with a standard 15-pin monitor connector, and is also compatible with the Apple IIgs (you'll also need a 15 kHz monitor for the GS).

First draft product information and usage info is now online at https://www.bigmessowires.com/mac-sync-inator/ Even if you can't be a tester, I would appreciate your feedback on the product info page, anything you felt was unclear or any important information that was missing. Thanks!


Well-known member
I'd be happy to test one, have like 8-10 Nubus graphic cards and a lot of machines including SE with external graphic, SE/30 with same etc. I do live in Sweden though... :)


Well-known member
I have an LC and a PowerBook 180 on the way, I'm open to test this gizmo. Will it unlock the LC's mystical 512x384 @ 16bpp mode that nobody has yet uncovered without a real Apple monitor? There's only one way to find out...

I'm in the US.
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Well-known member
@Jockelill DM me your address and I'll get you one. @luRaichu I'll put you on the list as well, though I may wait a bit first to look for more people with older / composite sync gear to test. Thanks! Anyone else interested?


Well-known member
Well, I’ve got a mix of standard Apple CRTs, modern LCDs, AudioVision 14, the IIgs and it’s original monitor, only two NuBus cards to try but also have some PCI cards in my PTPro…if any of that helps…then sure.


Well-known member
I'd be happy to test, I have an LC III and a Performa 6200, along with a handful of LCD monitors capable of interpreting VGA signals


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Maybe a few of us locals could pass a single adapter around, then we could test a bunch of equipment with just one adapter.


Well-known member
@bigmessowires let me know if you need me to testing anything. You might already have covered what I have but basically I've got the following monitors and cards, in addition to the computers in my signature:

4:3 VGA Monitors
  • DELL 15" e153Fpc LCD
  • Samsung SyncMaster 15" 512N
  • NEC Accusync 15" 52V (three copies of this)
Video Cards
  • SuperMac Spectrum 24 PDQ
  • SuperMac Spectrum 24/III
  • SuperMac Spectrum 24/IV
  • SuperMac Spectrum 24/V
  • Radius PrecisionColor 8xj
  • Apple Macintosh II Video Card (Toby)
  • Apple Macintosh II High Resolution Video Card
  • Apple 8*24 (non-GC) Video Card
And per @olePigeon, could share/handoff locally.


Well-known member
Thanks everyone, the first few beta units have been sent out today, but I'll look to get more made soon. Hopefully this will be generally available for everybody in about a month.


Well-known member
I'd be willing to test if it could help. System wise I have a fairly wide variety of Macs, pre-1995 these could be interesting: Desktops: IIci, IIsi, LC, Q700, IIvx, LCIII, C650, Q605, Q630. Laptops: PB165, PB180, PB540c, Duo Minidock, Duo Dock, Duo Dock II, Newer Tech UltraDock 16sce.

NuBus Video Cards:
E-Machines ColorLink SX/T
E-Machines Futura II
SuperMac Spectrum 8*24 PDQ
SuperMac Thunder 24 (v2.0.0a and v3.0.0)

Apple Multiple Scan 720
Apple Studio Display (original black and blue 15" LCD)
NEC LCD 1850E (supports sync-on-green)
ViewSonic VG150 (supports sync-on-green)
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Well-known member
@jmacz Only thing I can add to that:

4:3 / 5:4 displays:
  • Apple Color 13" CRT Monitor (640x480)
  • 15" Hitachi LCD
  • 17" IBM ThinkVision LCD
Video Cards:
  • Apple 80 Column / RGB Card for Apple ][ (I think this similar if not identical to the IIgs)
  • Apple ][ RamWorks III VGA adapter
  • Radius Precision Color Pro 24X
  • eMachines Futura II
  • Apple 8•24 GC (no RAM)


Well-known member
The RGB cards for the 8-bit II (both the 80-Column/RGB and RamWorks) are TTL (digital) RGB, the IIgs/Mac/VGA are analog RGB. It's possible to convert, but that's likely out of scope for what @bigmessowires is doing.


Well-known member
I’d be interested. I have a IIci with a Toby card, an AppleColor High-Resolution RGB Display and an Apple Multiscan 15AV that requires separate sync.


Well-known member
The RGB cards for the 8-bit II (both the 80-Column/RGB and RamWorks) are TTL (digital) RGB, the IIgs/Mac/VGA are analog RGB.
Do you mean the Apple II? Wouldn't those also have a different physical connector than the DB-15 used on early Macs?


Well-known member
If you end up needing more beta testers, I'd be interested. I have a bag of Mac-to-VGA adapters, a couple older VGA monitors and more than a few Macs and I don't think I have gotten either of the monitors to work with any Mac using any of the adapters.


Well-known member
I don't understand the post office. Shipped from California, at this rate the beta hardware sent to Sweden will arrive before hardware sent to Indiana. pokes at mailbox with stick

@NJRoadfan or @Arbee do you know where I could find the complete pinout for those TTL-level Apple II / Apple III cards? Is it RGB or RGBI (eight colors plus intensity)? It's almost surely out of scope for the Sync-inator, but maybe combined with another passive level shifter...