6500 db15 to vga adapter issues

[ouroboros]

Hey all, it is me again.

I'm trying to get this 6500 I have here to connect to a vga monitor, since that is all I have. I bought a DB15 to VGA adapter with 10 dip switches. This one here :

https://www.amazon.com/dp/B001I22L9C?psc=1&ref=ppx_yo2ov_dt_b_product_details

instructions are these :

Thing is, I can't get it to display an image. I've tried so many combinations and I've tried two different monitors and two different VGA cables. One is a Dell E178FPB and the other is a Viewsonic VX2457-mhd.

Now, I read that if you set the dip switches, and nothing is displayed, you need to turn the computer off and try again. I'm afraid I'm going to burn out the PSU or worse, ruin something else like the logicboard.

I know this is a long shot, but maybe I'm just not reading these instructions right and if anyone can point me in the right direction it would be very helpful. I've already found the DB15 adapter documentation thread, but I don't know...I'm just not winning here.

 

[joevt]

I would try one of the mode 5 modes (separate sync). Probably one of the multi sync modes.
21" 14679 // this might actually be the setting for MultiSync 16"
16" 14678 // this might actually be the setting for MultiSync 21"
14" 145789

Maybe you just need to boot to Open Firmware instead of trying to boot all the way to MacOS (if the default output option of Open Firmware is set to the graphics device). That way you don't need to worry about disk accesses. If nothing appears you can just press the power button to turn the computer off and try the next setting.

 

[François]

You don’t need a dip switches adapter for this Mac (none of the PPC Macs need one, I think?), a simple short adapter cable, or long, direct, db15 to vga cable will work. In those cables, pin 4 of the db15 plug (monitor sense 0) is open (not connected to anything), and pins 7 & 10 of the db15 (monitor sense 1 &2) are connected together.

 

[ouroboros]

I would try one of the mode 5 modes (separate sync). Probably one of the multi sync modes.
21" 14679 // this might actually be the setting for MultiSync 16"
16" 14678 // this might actually be the setting for MultiSync 21"
14" 145789

Maybe you just need to boot to Open Firmware instead of trying to boot all the way to MacOS (if the default output option of Open Firmware is set to the graphics device). That way you don't need to worry about disk accesses. If nothing appears you can just press the power button to turn the computer off and try the next setting.

Thanks! I was going by mode 1 and 2 and working my way down and then just gave up. I'll try these settings tonight!

You don’t need a dip switches adapter for this Mac (none of the PPC Macs need one, I think?), a simple short adapter cable, or long, direct, db15 to vga cable will work. In those cables, pin 4 of the db15 plug (monitor sense 0) is open (not connected to anything), and pins 7 & 10 of the db15 (monitor sense 1 &2) are connected together.

Thank you for the info...Could you send me an example of such cable? Something like this? I don't want to buy the wrong thing.

 

[François]

Could you send me an example of such cable? Something like this?

I’m pretty sure the cable you linked to won’t work at all. It really needs to be a video cable, specially wired to connect a Mac to a VGA monitor, and I don’t think they are manufactured anymore. Your best chance is the usual second hand buying and selling web sites. That’s were I found mine recently.

if you have the means to have the cable made, I can provide you with the wiring.

 

[Trash80toG4]

What resolution are you trying to set up?

 

[François]

This is the cable that I have:

I don’t see any brand name or logo on it, but there’s a part number (387-822A):

A closer look at the plugs:

 

[ouroboros]

This is the cable that I have:

View attachment 11806

I don’t see any brand name or logo on it, but there’s a part number (387-822A):

View attachment 11807

A closer look at the plugs:

View attachment 11808

Thank you! and thank you for offering the additional info. Unfortunately, I have no DB15 cables on hand to splice together. I did, however, find this nugget on ebay. I'm going to buy it regarless, but wanted to get your input -- do you think this is the same type of cable as yours? It says Radius, which worries me a little that it is a proprietary cable for a specific radius card, but unsure :

Radius Mac to VGA Video Cable p.n 590-0029-01 DB15 to HD15Monitor 6 ' | eBay

Find many great new & used options and get the best deals for Radius Mac to VGA Video Cable p.n 590-0029-01 DB15 to HD15Monitor 6 ' at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Thanks!

What resolution are you trying to set up?

Right now -- any resolution. The second monitor I'm trying supports up to 1080p so anything within that range.

 

[François]

That Radius cable could very well be proprietary for a Radius video card and its associated Radius monitor. So not at all wired correctly for Mac video to VGA. But that is a question for the specialists, I’m not well versed in the pre-PowerPC era of the Macintosh.

 

[ouroboros]

That Radius cable could very well be proprietary for a Radius video card and its associated Radius monitor. So not at all wired correctly for Mac video to VGA. But that is a question for the specialists, I’m not well versed in the pre-PowerPC era of the Macintosh.

Thanks! I reached out to the seller asking how he tested it. Hopefully they reply back shortly. Thanks again for all your help!

 

[Trash80toG4]

Since you're getting no image at all:

1 - have you checked to make sure the harness connection to the video board is firmly in place and undamaged?
2 - stick to testing at 640x480 and 800x600 which are 60Hz VGA outputs:
____VGA/SVGA setting in Column 3 of the table, looks to have 5 choices of modes, whatever the heck that means?


if your displays aren't good multisyncs, one of those settings should work.

 

[ouroboros]

At this point I have tried all different combinations. I'm going to get my Quadra 800 out of storage and see if maybe it is just the computer itself...The dedicated DB15 to VGA is arriving in the mail today, so I'll be able to test that out, too.