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Commodore 128 Video DAC Board Available

ajacocks

ajacocks

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All,

As discussed on commodore128.org, I am making available a new run of Richard42's video DAC board, which, along with a GBS-8220 (or similar) CGA-VGA converter, will enable high-quality 80-column RGB output, from the Commodore 128, to a VGA monitor.

There is a good picture of the output from the original run of these boards, at Commodore128.org.

My prices are as follows:

1. Bare PCB
Total (US): $10.00

2. Kit
Contains: bare PCB and components
Requires: soldering of component, GBS-8220 and power supply
Total (US): $40.00

3. Completed Board
Contains: populated PCB
What you need to do: Connect with your own CGA->VGA converter and power supply.
Total (US): $55.00

Thanks again to Richard42 for such a great design! I couldn't have done any of this without him. Sorry for the price increases over Richard, but a number of the parts have gone up in price, and so has shipping. I might be able to do better, if I get a number of orders.

This board will also work for IBM CGA, quite well.

Thanks!
- Alex
 
All the board build files that Richard42 created are available from a post on commodore128.org. I'll upload mine, with the mods that I made, as soon as I know that they work.

Thanks!
- Alex
 
ajacocks said:
This board will also work for IBM CGA, quite well.

Thanks!
- Alex
Click to expand...

Just to make sure I'm understanding correctly...this converter will take the TTL CGA output from and IBM PC or compatible machine and convert it to a nicely usable VGA output? Does it support the CGA intensity pin? I've been dreaming of such a thing...I'll be anxiously awaiting a confirmation! :)

Thanks,

Wesley
 
Wesley,

This board converts TTL RGBI to analog CGA suitable for use with an arcade-type CGA-to-VGA adapter, like the Gonbes GBS-8220. In combination with that board, the output is actually very good. The adapter is indeed designed for intensity (hence RGBI), but it was originally designed for a Commodore 128. I'll be happy to test, in any way that anyone wants, but I don't have a perfectly running PC, at the moment.

I'll let everyone here know when I get the test boards back from the PCB vendor, and build them up, to make sure that all is well.

Thanks!
- Alex
 
Alex,

That is excellent...I'm definitely interested in one. Do you have any links you can share with screenshots, etc? I looked but wasn't finding much...though it is late and I'm getting tired, could just be me! Also, the only board I saw was using surface-mount components...but I'm not sure if that was yours or not...is yours a surface-mount design, or through-hole? I can solder through-hole, but I don't think I'm up to that much surface-mount yet...in which case I would need to opt for buying an assembled one.

Thanks!

Wesley
 
Someguy: Yeah, to the arcade guys, "CGA" means 15Hz analog signalling.

Wesley: The board is entirely through-hole, and should be easy for a journeyman builder to assemble.

I'll work on taking some screenshots of my own, but this is from the original run:
http://www.commodore128.org/index.php?topic=3877.msg19829#msg19829

Here is the front of the board:
front.jpg
And here is the back:
back.jpg

Thanks!
- Alex
 
That's awesome, and certainly something I feel comfy tackling. Definitely would like to buy one when they come available...maybe even two.

Thanks!!

Wesley
 
I have one of these back from when Richard originally offered them. It's a good deal. If you have a VGA monitor capable of doing CGA, you probably won't even need a VGA converter, just a 9-15 pin adapter.
 
Yep. Though, I don't know how common those are, unless you have a multisync CRT. I have seen on eBay some new LCDs that are meant to be arcade display replacements that claim to take CGA/EGA as inputs, but those are definitely analog, and not digital.

They should work nicely with this DAC, though. I very much would like to do a new version of this DAC that supports EGA, but that's a future project.

- Alex
 
I have an older Coby LCD, I think it is a model TV-TF1514 I was able to connect it directly to my Atari MegaSTE and run both low res and medium res modes (they're both CGA modes; high res mode is VGA-ish enough that it also worked).
 
Glad to hear that some folks are still interested.

To update on status, the prototype boards have been sent to the fab, and I should have them back by January 29th. Once I build and verify those, I will make the production order, and will hopefully get those back within 2 weeks, so I should be able to start shipping boards and kits around the middle of February. I have already gotten the parts from DigiKey for my prototype.

Thanks!
- Alex
 
Alex,

Thanks for the update and your work on these...I'll be looking forward to having one! If you ever work out an EGA version, you can count me in for one of those too!!

Thanks,

Wesley
 
Just to give another update, I should have the prototype board in hand, on Monday. However, my company is sending me on travel, next week. So, I should have the completed prototype next weekend, and assuming that it works, I will start taking orders then.

Thanks!
- Alex
 
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