Video DAC Assembly Information

This post is taken directly from a post that I made on Erik Klein's Vintage Computing Forums.
Here are a list of the parts required to build the video DAC.

Qty	Reference	Part Number	Description
1	R13	309XBK-ND	RES 309 OHM 1/4W 1% METAL FILM
1	R14	324XBK-ND	RES 324 OHM 1/4W 1% METAL FILM
1	R15	365XBK-ND	RES 365 OHM 1/4W 1% METAL FILM
2	R4,R5	4.64KXBK-ND	RES 4.64K OHM 1/4W 1% METAL FILM
1	R6	4.32KXBK-ND	RES 4.32K OHM 1/4W 1% METAL FILM
1	R19	13.0KXBK-ND	RES 13.0K OHM 1/4W 1% METAL FILM
3	R10,R11,R12	10.0KXBK-ND	RES 10.0K OHM 1/4W 1% METAL FILM
3	R7,R8,R9	15.0KXBK-ND	RES 15.0K OHM 1/4W 1% METAL FILM
4	R3,R16,R17,R18	75QBK-ND	RES 75 OHM 1/4W 5% CARBON FILM
1	R1	2.2KQBK-ND	RES 2.2K OHM 1/4W 5% CARBON FILM
1	R2	3.3KQBK-ND	RES 3.3K OHM 1/4W 5% CARBON FILM
4	C2,C3,C4,C5	478-3193-ND	CAP CER 0.1UF 50V 20% RADIAL
1	C1	493-1144-ND	CAP ALUM 10UF 100V 20% RADIAL
1	IC2	296-3577-5-ND	IC TRIPLE 3-IN NOR GATE 14-DIP
1	IC1	TC74ACT244PF-ND	IC BUFF/DVR TRI-ST DUAL 20DIP
1	IC3	296-4348-5-ND	IC QUAD 2IN POS-NAND GATE 14-DIP
1	X1	621-009-260-042-ND	CONN DSUB PLUG 9POS R/A GOLD
1	IC4	AD8044ANZ-ND	IC OPAMP VF R-R QUAD LP 14DIP
1	POWER	A1921-ND	CONN HEADER VERT 2POS .100 TIN
1	H2	A1923-ND	CONN HEADER VERT 6POS .100 TIN

And, the pinout of the H2 (video) connection, from left to right, with the DE-9 connector facing up, is:

Ground, horizontal sync, vertical sync, red, green, blue

The power connection pinout, from left to right, is:

+5 VDC, ground

The GBS-8220 board comes with 2 pigtails. Plug them in, as described in the 8220 manual, and the video DAC will be powered by downstream power from the 8220. Power the 8220 with a standard AC/DC power adapter.

You can use the following parts, from DigiKey, to put connectors onto the supplied pigtails, that will plug in to the DAC board.

Qty	Part Number	Description
8	A100453CT-ND	CONN SOCKET 22-26AWG TIN CRIMP
1	A99617-ND	CONN RCPT HSNG 6POS CST-100 II
1	A99613-ND	CONN RCPT HSNG 2POS CST-100 II

The DAC can be plugged directly in to either a Commodore 128 RGB connector, or to the back of a CGA or EGA IBM video card. Please note that, on an EGA card, the DAC only works in the CGA (low-res) modes, and not in 640x350.

In response to a number of requests, here is the schematic.  It's a bit messy, but it should be usable.

Parts Inventory

Just a quick note on my inventory:

Description	Quantity on Hand	Quantity on Order
C128 DAC PCB	4	0
DAC Parts Kit	6	0

Unless I say that I have parts in stock, here, any orders will be shipped as soon as their parts come in. Negative inventories represent orders received for which I do not yet have the parts.

Commodore 128/ CGA Video DAC Board Available

I just completed a new build of Richard42's fantastic Commodore 128 video DAC board.  This is a fantastic little board that, in combination with a Gonbes GBS-8220 arcade RGB scaler, produces great 16 color, with intensity, output on any modern VGA monitor.  To boot, the combination also works great with IBM CGA or low-res EGA cards!

I did two rounds of prototypes, and the following is what the final board looks like.  Please excuse the poor quality of my living-room photos.

Video DAC Front

Video DAC Back

I am now making these available to the vintage community for the price of what the components cost me, plus shipping.

If you would like to purchase one, I am offering several different ways to get it.

Please let me know if you have any comments. I'll work on getting some screenshots, as I was referring to some posted on Commodore128.org, but that forum seems to have gone down, rather unexpectedly.