HDI-45 to VGA DIY attempt

[somedude]

Hello again,

Since I learned that there are adapters available to connect HDI-45 to 2 row 15 pin and then to 3 row 15 pin VGA, I figured there should be a way to make an adapter.

This page: http://home.scarlet.be/~tsc06806/app_moni.htm has a good pinout description for HDI-45 and VGA is ubiquitous.

I noticed that the analog pins are grouped to one side of the connector, making a connection a bit easier.

The pin spacing is a hybrid 0.1" and 2mm, but having them grouped should allow me to use 0.1" headers, soldered onto a perforated board.

Row spacing might be an issue, but I will try to bend the pins so that they fit.

Having said that, here is my question: do you think I can get it to work by only connecting the analog pins?

HDI-45 also has 3 Monitor ID pins that could connect to the VGA monitor ID pins, although I couldn't find a proper mapping anywhere.

Are there any other pins that I might have to ground or maybe even pull-up to enable the monitor to work?

There might be some detection pin that I am not aware of.

And finally, C sync seems to be only available on the HDI and not VGA. No idea what the C stands for either, chroma, composite maybe?

Thank you for any clues.

Please don't be gentle if you think this is insane.

Edit: this site has some good mapping info: https://www.cs.rochester.edu/~kparkins/pinouts.txt

 

[somedude]

I have a basic connection, where I used the 2 row Apple connector as an intermediate reference:

HDI-45 - DE-15

8 - 11  OPEN to enable VGA mode (this might change)

9 - 12  (Connect to HDI 18 to enable VGA mode)

10 - 7  G gnd

11 - 2  G

18 - 4  (Connect to HDI 9 to enable VGA mode)

26 - 6  R gnd

27 - 1  R

33 - 14  V sync

42 - 13  H sync

43 - 10  V sync gnd

44 - 8  B gnd

45 - 3  B

There are also the monitor ID pins 31, 32 and 41 that I will try to leave unconnected.

I might also have to play around with the sense pins 8, 9 and 18 to force certain modes, if VGA modes won't work.

Any feedback would be greatly appreciated.

 

[Bunsen]

Moved to Nubus Powermac forum.

This is something I've looked briefly into doing myself, so I'm glad to see someone experimenting with it.  My thinking was to attach a permanent VGA out to the back panel, hot-wired to the solder pads under the HDI-45.

As to sense pins: I think if you leave them out altogether, you can use the Monitors control panel to set your resolution & sync.  If I'm mistaken about that, I'm sure someone will speak up shortly.

 

[somedude]

Thank you, Doctor,

At least no-one said I should stop pursuing this insane idea.

I will post results after I build it and try it out.

By the way, you moved the topic - where did I have it before?

I thought I had picked the sub forum carefully...

 

[Cory5412]

There's no good reason this isn't do-able. When you use Apple's HDI45 adapter, you can further put any normal VGA adapter (either one that makes you set fixed-sync modes, or a multi sync adapter) and you will be able to use PC monitors that way.

Are there any sources for HDI45 shells and connectors  or are you looking more to just adapt one system or manually wire in adapters as you need?

Good luck!

 

[Floofies]

I like this project. I've been planning on making my own drop-in VGA replacement for Q630 DB-15 monitor-out boards.

Definitely keeping an eye on this one.

 

[Bunsen]

By the way, you moved the topic - where did I have it before?

It was in PCI Powermacs - the 6100 is a Nubus Powermac.

 

[somedude]

Thanks guys,

I do not have any source for connectors and that is why I am attempting to make one.

All I have is a female VGA connector on a header, stripped from a burned out card.

If it works, I will try to make it look reasonable, but the first one will likely be an ugly hack.

I assume that the multi sync adapter has the sense pins floating?

This is where info is scarce and the reason for not having started soldering yet.

Well, there is one more reason - I can't find info on how thick pins are on the HDI-45, so I will try 0.1" at first.

@Bunsen: makes sense, I didn't know at the time this was a NuBus, sorry about that.

 

[somedude]

I have a connector, sort of.

I used a 2mm pitch perf board with tinned through holes and the pins from male headers.

Two of the rows were offset by half a mm so I bent the base of the pins.

It's not yet soldered, but seems to fit and I only used enough pins for the analog signals, which are all grouped to one side.

The other side will be the VGA connector but I haven't decided to cut the ribbon and solder the wires or use a male header soldered to another intermediate board. I think it will look cleaner with the wires soldered onto my make-shift HDI connector.

Once I solder it, I will post results and a picture, unless it's too ugly.... Nah, I will post it anyway...

 

[beachycove]

I can sell you one of the standard hdi-45 to db15 adapters for a 6100....

Location is in Ontario, which may or may not be useful for someone in the great white north to know, postage-wise.

 

[somedude]

Thank you, if I can't get it to work, I will reach out. I'm in the GTA.

 

[somedude]

The good news is that the adapter is complete.

The bad news is that I still don't have video.

A voltmeter proved that there aren't enough electrons in the pram battery, as it only measures 0.06V.

Upon further examination, the date stamp on it is 97, so....

In spite of trying the double-tap method a few times, with different pauses, no video. I stopped because I couldn't take it any more.

I was getting the chime, though.

I see three possibilities:

- dead video

- my LCD is not able to work vith the signal

- the battery must be replaced.

I sincerely hope it's the battery. I have a small flaslight that takes 4 AAA batteries and I will try to get 3 rechargeable ones in there and a shunt for the fourth, for a total of 3.6V.

If not.....

The only pins connected on the adapter are the 3 color and 2 sync, together with their corresponding grounds.

I left out the DDC and the 9V pins on the VGA dongle and I didn't do anything with the sense pins.

If I still get nothing with the battery, I will try to force 640x480 VGA with the sense pins.

Any suggestions would be greatly appreciated.

 

[tanaquil]

You can purchase a new PRAM battery for less than $10 at OWC. I don't see why you'd chain AAAs unless you like hacking for its own sake.

Good luck! The cable project is beyond my skill set.

 

[somedude]

Well, I don't want to spend a dime until I know for a fact that the machine works.

Then I will rebuild it properly and start hunting for the right adapters and components.

But for now, I'm simply aiming to see something on the monitor.

Here are a couple of pics of the "adapter".

 

[somedude]

Still no dice.

I got the battery hooked up, measured 3.6V on the battery holder.

Turned it on, I got the chime but no video.

I triple checked the adapter for continuity and shorts.

Tried 2 different LCDs, that's all I have, not a blink.

If I push the left button at the back, I get the chime, the same one I get at power on.

Now if I push the button on the right i get a loud car crashing sound!

What's that about?

There is no NuBus terminator and info on it is conflicting at best.

I doubt that the previous owner knew enough to pull it, if there ever was one.

I will probably try to play with the sense pins at this point, as I have no idea what else to do.

 

[somedude]

WOO-HOO!!!

We have lift-off!!!

Working with the sense pins fixed the issue.

I can only get 640x480 by forcing rgb14" mode and VGA/SVGA mode.

Even though I tried forcing rgb19" to get 1024x768, it didn't like it.

I hope I will be able to set 1024x768 through software in VGA/SVGA mode.

Thank you all for the moral support.

 

[MJ313]

Well done, sir, way to stick with it!

 

[somedude]

Thank you very much, in retrospect, it was a fun project.

I actually played around with the sense pins, now that I have them on jumpers.

I can easily get 640x480 and 832x624, but not higher, by forcing rgb modes.

VGA/SVGA mode also works and I am hoping to be able to get to 1024x768 in SVGA mode through the operating system.

But that's a different post altogether, as I now need ADB peripherals.

 

[Bunsen]

Hey congratulations!  I'm really glad to hear this worked out.

Mind if I ask where you found the perf board with the correct spacing?

am hoping to be able to get to 1024x768

I could be wrong, but I think the motherboard video actually tops out at 832x624 on those. kan.org will know.