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Quadra 610 video output question
Posted by: Ttpilot on 2025-03-11 16:48:24 I picked up a Quadra 610 this week that is in working condition. It chimes at startup and I can hear the hard drive spinning up and booting the machine. However, I get no video. I have an old Dell 4:3 VGA monitor and have connected it with a PTC Mac to VGA adapter (10 switches) and also a more generic Mac to VGA adapter (no switches). Neither one gives me a video signal on the monitor and I've had no luck figuring out the correct switch combination to get it to work. Has anyone had any luck with one of these?
Posted by: dougg3 on 2025-03-11 19:40:04 Hmmm...for what it's worth, I just tested my Centris 610 with a random Mac-to-VGA adapter (no switches, I think it picks normal VGA mode) and it works great. With a 10-switch adapter just like the one BMOW pictured at this link, it also works great with switches 2, 3, 6, and 7 on. That sets it for VGA mode and passes through HSYNC and VSYNC. It might be worth double-checking to make sure the mode you have selected with the 10-switch adapter is the "separate sync" mode. From what I can see the 610 doesn't output sync on green when VGA mode is selected, so you need HSYNC and VSYNC. Another combination that works for me is Apple 13" RGB mode with switches 1 and 4 on. Your monitor might have trouble though because it's not a standard 60 Hz VGA signal in that case. This uses sync on green, but you could also turn on switch 5 (or maybe 6 and 7) to try to pass through sync signals for that mode. Typically when people ask this question, someone always chimes in mentioning how some Macs have trouble with the video not working if the PRAM battery is dead/removed, but I can confirm that the 610's video works totally fine without a battery, so you don't have to worry about that. Just tested it here. Good luck!
Posted by: Forrest on 2025-03-16 18:58:59 Depending on the switch settings, you should be able to get 640 x 480, 800 x 600, 832 x 624 and 1024 x 768 on a VGA monitor. Adding a VRAM SIMM will get you more colors in each mode.
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