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TAM hack: Apple External Video Connector
Posted by: Byrd on 2019-01-03 01:18:27
Hi all,

Most 5x00, 6x00 and 580 Macs come with a small connector on the motherboard for external video support.  Apple made an adapter, part M4099LL/A which provides functionality for a mirrored display output (not dual display sadly) for these machines.

The TAM being based off a 5500/6500 board also has this connector, but no-where to mount the DB15 port.  My lowly USB card has enough space to fit the connector with just enough room for a DB15 to VGA adapter on the other side.  In doing so, it's great to be able to plug the TAM video output to an external monitor, TV or projector!  It's an exact mirror ouput with no performance hit.

JB

IMG_4932.JPG

IMG_4934.JPG
Posted by: Trash80toHP_Mini on 2019-01-03 07:14:17
Very, very sweet hack, Byrd.
Posted by: daanvdl on 2024-12-08 04:05:37
I reverse engineered the GIMO. For those who are interested, you can now build your own:
github.com

GitHub - daanvdl/M4099LL-B: Apple Macintosh External Video Connector M4099LL/B Recreation

Apple Macintosh External Video Connector M4099LL/B Recreation - daanvdl/M4099LL-B
github.com github.com
Posted by: chiptripper on 2024-12-09 19:48:35
I reverse engineered the GIMO. For those who are interested, you can now build your own:
github.com

GitHub - daanvdl/M4099LL-B: Apple Macintosh External Video Connector M4099LL/B Recreation

Apple Macintosh External Video Connector M4099LL/B Recreation - daanvdl/M4099LL-B
github.com github.com
Very cool, thanks for this!
Posted by: Trash80toHP_Mini on 2024-12-10 08:09:44
Wild stuff! Is full VGA adaptation implemented on your adapter? I've only seen straight thru to standard MAC DA15 cables ere this.
Posted by: LaPorta on 2024-12-10 09:48:09
This would have been cool as a legit Apple add on...though I am sure they would have never!
Posted by: cheesestraws on 2024-12-18 13:46:13
This would have been cool as a legit Apple add on...though I am sure they would have never!

It was an Apple part! I've got an original one somewhere
Posted by: daanvdl on 2025-01-07 05:34:35
Wild stuff! Is full VGA adaptation implemented on your adapter? I've only seen straight thru to standard MAC DA15 cables ere this.
Yes, i also created a VGA variant which is also available in the linked GIT repository.
Posted by: Trash80toHP_Mini on 2025-01-07 08:48:13
Excellent, opens up an alternative for my notion for integrating the TAM into a KVM equipped primary workstation setup.

TAM/6500 resolution is much too low for 21" TPD tastes developed in the day. VidCard required. which opens up higher resolutions on the primary workstation display with onboard display as second screen.

Your approach puts TAM output on primary display sans slot sacrifice. 😉
Posted by: Trash80toHP_Mini on 2025-01-07 08:49:31
Excellent, opens up an alternative for my notion for integrating the TAM into a KVM equipped primary workstation setup.

TAM/6500 resolution is much too low for 21" TPD tastes developed in the day. VidCard required. This opens up higher resolutions feed for primary workstation display with onboard display as second screen.

Your approach puts TAM output on primary display sans slot sacrifice. 😉
Posted by: DarthNvader on 2025-01-17 09:16:33
Hi all,

Most 5x00, 6x00 and 580 Macs come with a small connector on the motherboard for external video support. Apple made an adapter, part M4099LL/A which provides functionality for a mirrored display output (not dual display sadly) for these machines.

The TAM being based off a 5500/6500 board also has this connector, but no-where to mount the DB15 port. My lowly USB card has enough space to fit the connector with just enough room for a DB15 to VGA adapter on the other side. In doing so, it's great to be able to plug the TAM video output to an external monitor, TV or projector! It's an exact mirror ouput with no performance hit.

JB

View attachment 19094

View attachment 19095
The 7200/120 I had had a connector I never could figure out what it was on the logic board, could this be the same connector?

It can be seen here just behind the Mac VGA connector, brown mini slot:

s-l1600.jpg
Posted by: DarthNvader on 2025-01-17 09:28:49
That has to be what it is, it has the same socket from what I can tell. 5 pins, then the tab and 6 pins.
Posted by: Byrd on 2025-01-17 13:37:33
Yes same connector utilised for the 7”
DOS Compatibility card as found in some 7200 models
Posted by: DarthNvader on 2025-01-18 08:17:44
Yes same connector utilised for the 7”
DOS Compatibility card as found in some 7200 models
Can you elaborate on that a bit?
Posted by: Byrd on 2025-01-18 11:17:12
The PowerMac 7200 came in a DOS compatible edition with a 486-based (Cyrix) PCI card that feeds back video to this same GMIO connector. Also tried same card and connector in a TAM however the internal LCD does not output the right refresh/resolution, needs an external monitor.
Posted by: DarthNvader on 2025-01-18 17:10:30
The PowerMac 7200 came in a DOS compatible edition with a 486-based (Cyrix) PCI card that feeds back video to this same GMIO connector. Also tried same card and connector in a TAM however the internal LCD does not output the right refresh/resolution, needs an external monitor.
So the 7200 PC card didn't have that odd ball Y-video cable, it used the GMIO?
Posted by: Byrd on 2025-01-18 20:34:02
It could use both
Posted by: DarthNvader on 2025-01-19 03:22:58
It could use both
Seems most of the used PC compatibility cards have lost the internal audio/video assembly( cable/rinser ) Does anyone know the Apple part number for it?

Did the 12" PC compatibility Cards have the socket for the internal cable as well?
Posted by: Trekintosh on 2025-02-03 12:25:00
Thanks for the heads up on this, someone was selling an unused one for like $20 on ebay so I snapped it up for my 5500(ish) project, so I can stream it out on my twitch.
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