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Use Quadra Display On Newer Mac w/ Gender Changer?

R

reodraca

Active member
If this is the wrong topic section, my apologies. This display did come with a Quadra, so it's my best guess.

I was wondering if I could use my Macintosh 16" Color Display on my much newer Power Mac G4 if I use an Apple DB15 to VGA adapter in conjunction with a DB15 female-to-female gender changer. The Power Mac G4 does support the display's fixed resolution of 832x624 at 75 Hz (just checked, and the flat panel I currently have hooked up to it is set to that exact res and frequency), but is that all that's required for it to work? Is there an ID signal carried by the older Mac video standard that wouldn't be compatible with the newer VGA ID signal?

I can always just try it, but I'd rather ask first so I don't destroy a perfectly good 30 year old Trinitron monitor, nor my dual 500 G4.

Thanks in advance.
 
Phipli

Phipli

Well-known member
The common mac 15 pin dsub to VGA adapters are designed to work in the other direction and a gender changer wouldn't fix that. Adapters for the other direction probably do exist, or you could make one :) it wouldn't be too complex.

Don't plug it in with what you described :)

Have you considered picking up a PCI graphics card with the Mac video connector? A Rage II or a TwinTurbo or something? A fairly easy solution. A bit more care chosing the card might be needed if you plan to run OSX.
 
R

reodraca

Active member
Phipli said:
The common mac 15 pin dsub to VGA adapters are designed to work in the other direction and a gender changer wouldn't fix that. Adapters for the other direction probably do exist, or you could make one :) it wouldn't be too complex.

Don't plug it in with what you described :)

Have you considered picking up a PCI graphics card with the Mac video connector? A Rage II or a TwinTurbo or something? A fairly easy solution. A bit more care chosing the card might be needed if you plan to run OSX.
Click to expand...
I tried to get a TwinTurbo PCI I had from a Power Mac 8600 to work in my G4 but it refused to display anything, regardless of whether I plugged anything into the Mac DB15 or the VGA port (the card had both).

I'll look for an old Rage II or Rage Pro PCI and try that. Thanks for the tip.
 
C

Cory5412

Daring Pioneer of the Future
Staff member
reodraca said:
Macintosh 16" Color Display
Click to expand...

It depends on which machine, and it will likely only work with Apple's original video cards, or previous-era video cards you install into PCI slots.

It should work with Apple's passive adapter

What G4 and graphics do you have? If it's a Digital Audio or earlier it will probably work but I say that with the caution that I haven't tried mine in that config (yet).

If it's an MDD? likely won't work.
 
R

reodraca

Active member
Cory5412 said:
It depends on which machine, and it will likely only work with Apple's original video cards, or previous-era video cards you install into PCI slots.

It should work with Apple's passive adapter

What G4 and graphics do you have? If it's a Digital Audio or earlier it will probably work but I say that with the caution that I haven't tried mine in that config (yet).

If it's an MDD? likely won't work.
Click to expand...
It's a Gigabit Ethernet. The first one available with dual G4's. I'm honestly scared of picking up a MDD due to the high failure rate of the wind tunnel power supplies.

Passive adapter? Are you referring to the typical adapter that lets VGA monitors work on classic Macs?
 
sfiera

sfiera

Well-known member
There are a few things I’d consider:
  • Driving the monitor with the wrong resolution or rate could damage it. Are you sure that you’ll never accidentally use the wrong settings? (if you zap the PRAM, or the PRAM battery dies, or you just change something in the control panel)
  • Does the monitor use separate sync or composite sync? VGA only carries separate sync, but DA-15 carries both, so some Apple monitors use one and some use the other. If the monitor expects composite sync, extra circuitry is needed.
  • What settings does the display adapter have? A 4- or 6-switch DA-15-to-VGA adapter probably only touches the sense lines, so it might work in the other direction. A 10-switch adapter would touch the sync and green lines too, and might not.
I don’t know if the G4 will expect any sort of VGA ID. I’d guess not, since you’re already using an un-VGA-like 832×624 resolution—but the lack of an ID creates a risk of using the wrong settings.
 
R

reodraca

Active member
sfiera said:
There are a few things I’d consider:
  • Driving the monitor with the wrong resolution or rate could damage it. Are you sure that you’ll never accidentally use the wrong settings? (if you zap the PRAM, or the PRAM battery dies, or you just change something in the control panel)
  • Does the monitor use separate sync or composite sync? VGA only carries separate sync, but DA-15 carries both, so some Apple monitors use one and some use the other. If the monitor expects composite sync, extra circuitry is needed.
  • What settings does the display adapter have? A 4- or 6-switch DA-15-to-VGA adapter probably only touches the sense lines, so it might work in the other direction. A 10-switch adapter would touch the sync and green lines too, and might not.
I don’t know if the G4 will expect any sort of VGA ID. I’d guess not, since you’re already using an un-VGA-like 832×624 resolution—but the lack of an ID creates a risk of using the wrong settings.
Click to expand...
I'm currently using a VGA LCD screen on a VGA card set at 832x624 75Hz, which was one of the standard resolutions I could select in OS 9 (among 640x480 thru 1280x1024 & 60-75Hz). I am going to assume that it's definitely a VGA signal.

As for having to zap the pram, if i ever need to do so, I'd just be careful and remember to use a different monitor to set the res and refresh back to the old tube's native ones before plugging it back in.

I have no idea whether the old tube uses separate or composite sync. I'd have to try and find some Apple documentation for it to find out. For now, though, I'm not convinced it'd work, and I don't like to recklessly experiment with pieces of computer history.

Thanks for the reply and food for thought.
 
Phipli

Phipli

Well-known member

If it was just wired like the above it would be ok - I was worried about the diodes, but they're isolated from the VGA side and you'd just end up having two unpowered diodes on the monitor side.

I'd want to sit down and make sure the signals were going where I was expecting using a continuity tester before plugging anything in.

Weird the TwinTurbo doesn't work.
 
C

Cory5412

Daring Pioneer of the Future
Staff member
reodraca said:
Passive adapter? Are you referring to the typical adapter that lets VGA monitors work on classic Macs?
Click to expand...

The opposite direction, it lets Apple's DA15 monitors be used on DB15 ports. It was included with many newer and higher end monitors than the MCD16. They were also included with some PowerBooks that switched to VGA before the rest of the Macs did.

Mine is Apple part number 590-1120-A. (I'm in the US, I don't know if these were localized or there's revisions or anything.)
 
R

reodraca

Active member
Cory5412 said:
The opposite direction, it lets Apple's DA15 monitors be used on DB15 ports. It was included with many newer and higher end monitors than the MCD16. They were also included with some PowerBooks that switched to VGA before the rest of the Macs did.

Mine is Apple part number 590-1120-A. (I'm in the US, I don't know if these were localized or there's revisions or anything.)
Click to expand...
I had absolutely no idea those existed. Either that, or I didn't look closely enough and just thought those were apple branded adapters that allowed VGA monitors to be used on older Macs.

Thank you. Something tells me that is my best bet, because if it was already made by Apple, then it's wired correctly. If that doesn't work with my Mac 16" Color Display, I don't think it'll work with anything.
 
R

reodraca

Active member
cheesestraws said:
They do, I bought one by mistake a couple of years ago. OP, on the offchance you're in the UK, I can drop it in the post to you if I can find it...
Click to expand...
I appreciate that. Chances are I'll already be picking one up off of eBay by the time you locate it, because I'm admittedly no good with patience, but thank you for the offer.
 
Phipli

Phipli

Well-known member
LaPorta said:
I have some type of TwinTurbo 128 that is in my PT Pro, and that thing runs under 7.5.5 even on that machine.
Click to expand...
They have a G4, they're probably running OS9 or OSX... I want to know about it if they're running 7.5.5 on a New world G4! ;)
 
R

reodraca

Active member
Phipli said:
They have a G4, they're probably running OS9 or OSX... I want to know about it if they're running 7.5.5 on a New world G4! ;)
Click to expand...
It really would be wonderful if System 7 worked on a New World ROM. Sad. It's my favorite OS, for sure.
 
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