misterblack
Fixin' in the basement
Hello all, I have a "Video 7 Enhancer IIe" RGB card and I wanted to share a little info about the card. There doesn't seem to be much info out there about it, so here goes.
This is a RGB _and_ Composite video output card for the Apple IIe and it plugs into the AUX slot. It gives the machine the AUX 64k bank to allow full functionality like Double Hi-res and running programs that need a 128k machine.
RGB is created inside a custom "Wafer Scale" IC which takes the serial video signal and sync provided from the AUX slot and turns that into RGB. Sadly that means there is nothing we can reverse engineer with this device. Two 74LS logic ICs and eight 4164 ICs support the RAM expansion. This makes the RGB output a single chip system, and from what I understand, a version of this was put into a little module that plugs into the Apple IIc video expansion port to provide RGB. (Yep, the video signals on the IIc DB15 and the IIe AUX are basically identical.)
The card outputs RGB using a DE9 connector using the IBM CGA standard and pinout. (RGB + Intensity + H-Sync + V-Sync) It does NOT use the Apple X-RGB encoding scheme that other RGB cards use like the Apple IIe RGB card and Apple ///. This means that colors look mostly correct using any bog standard CGA compatible monitor including the Commodore 1084 and IBM 5153. The main exception being that Orange is rendered as "Light Red" as CGA does not have the color Orange.
Luckily it uses the CGA Brown to render that color correctly, which is frankly closer to the intended brown the the vomit color brown typically rendered on NTSC monitors. I'll post some photos in the next post with examples of the color rendering.
The timing output from the card is an exact match to CGA, so things like the RGB2HDMI work perfectly with it using the CGA profile. I assume this might vary depending on the exact timing on your Apple IIe, though.
The card features two DIP switches to select the font color in text mode:
Green 1+2 Up
Yellow 1 Up, 2 Down
Cyan 1 Down, 2 Up
White 1+2 Down
Text is visible on the lower 4 lines is rendered in the selected color even in mixed graphics/text mode. The text color does NOT affect the graphics, so double high res in monochrome (which is set with the when running Apple II Desktop) is rendered in white and is not affected by the DIP switches.
Now onto the composite video output, this is pretty neat and something I personally hadn't seen before. The composite video signal is built using a simple resistor DAC from an RGB-like signal output from the Wafer Scale IC. That means instead of a typical vertical line representation of the colors you always see from an Apple II when using a monochrome monitor, you see 16 shades of gray! Yep, the signal does not have a color burst, so it is a nicely shaded super high resolution monochrome signal! It frankly makes things look super awesome!
I did notice one issue though: When connecting to my Apple IIc monitor to the card, the video signal was way too hot. (Bright, voltage too high.) I had to turn the contrast way down or the signal was super blown out. Connecting the scope showed the video signal had a peak to peak voltage of almost 3 volts! (This is way too hot for NTSC which should be closer to 1v P2P) There is also pretty ugly ghosting due to ringing, likely created inside the monitor as it's not really designed to handle such a hot signal.
I sketched out the video output circuit, which uses a NPN transistor as a simple buffer for the video signal. The people who made this card used a 75 ohm resistor in-line with the output, which might seem right for video termination with paired with the 75 ohm to ground inside the monitor, but this isn't right for a 5V signal with only 100 ohms to ground. (See picture below)
To fix this problem, just remove R13 and replace it with a 220ohm resistor, which brings the video output in-line with what it should be and makes the monitor much happier. Unfortunately, the marking R13 is impossible to read with the resistors in place, so looking at the front of the board, go to the top right corner below the 10 pin header connector. You will see a bank of 5 resistors just to the right of the DIP switches. R13 is the resistor one over from the right edge of the board.
That simple fix removes the ghosting and makes the levels roughly the same as the IIe's built in video! Easy fix for an awesome video output!
One other small caveat, the video is shifted over to the left on the Enhancer IIe versus the IIe's built in video output. I personally feel the Apple IIe and IIc video is shifted too far to the right versus other 8-bit computers... I assume there is some delay somewhere in the circuit on the motherboard causing this, and I'm not sure if this was by design by Apple. Even though the Enhancer IIe is using the provided sync and serial video stream from the motherboard, compared to the motherboard video, it looks shifted over. (You can see this in the photos on the next post.)
Anyway I hope this info was helpful! The Enhancer IIc composite output (if it has it) may also have same issue with the video being too hot. The resistor fix would help there too.
Thanks to BigSteve for giving me this card after finding it at at a recent. When I was a kid with my Apple IIc I would have been over the moon to have the Enhancer IIc! I remember seeing it in magazine ads and lusting over it, but it was far too out of my price range, especially as I didn't have a Digital RGB monitor anyway.
--Adrian
This is a RGB _and_ Composite video output card for the Apple IIe and it plugs into the AUX slot. It gives the machine the AUX 64k bank to allow full functionality like Double Hi-res and running programs that need a 128k machine.
RGB is created inside a custom "Wafer Scale" IC which takes the serial video signal and sync provided from the AUX slot and turns that into RGB. Sadly that means there is nothing we can reverse engineer with this device. Two 74LS logic ICs and eight 4164 ICs support the RAM expansion. This makes the RGB output a single chip system, and from what I understand, a version of this was put into a little module that plugs into the Apple IIc video expansion port to provide RGB. (Yep, the video signals on the IIc DB15 and the IIe AUX are basically identical.)
The card outputs RGB using a DE9 connector using the IBM CGA standard and pinout. (RGB + Intensity + H-Sync + V-Sync) It does NOT use the Apple X-RGB encoding scheme that other RGB cards use like the Apple IIe RGB card and Apple ///. This means that colors look mostly correct using any bog standard CGA compatible monitor including the Commodore 1084 and IBM 5153. The main exception being that Orange is rendered as "Light Red" as CGA does not have the color Orange.
Luckily it uses the CGA Brown to render that color correctly, which is frankly closer to the intended brown the the vomit color brown typically rendered on NTSC monitors. I'll post some photos in the next post with examples of the color rendering.
The timing output from the card is an exact match to CGA, so things like the RGB2HDMI work perfectly with it using the CGA profile. I assume this might vary depending on the exact timing on your Apple IIe, though.
The card features two DIP switches to select the font color in text mode:
Green 1+2 Up
Yellow 1 Up, 2 Down
Cyan 1 Down, 2 Up
White 1+2 Down
Text is visible on the lower 4 lines is rendered in the selected color even in mixed graphics/text mode. The text color does NOT affect the graphics, so double high res in monochrome (which is set with the when running Apple II Desktop) is rendered in white and is not affected by the DIP switches.
Now onto the composite video output, this is pretty neat and something I personally hadn't seen before. The composite video signal is built using a simple resistor DAC from an RGB-like signal output from the Wafer Scale IC. That means instead of a typical vertical line representation of the colors you always see from an Apple II when using a monochrome monitor, you see 16 shades of gray! Yep, the signal does not have a color burst, so it is a nicely shaded super high resolution monochrome signal! It frankly makes things look super awesome!
I did notice one issue though: When connecting to my Apple IIc monitor to the card, the video signal was way too hot. (Bright, voltage too high.) I had to turn the contrast way down or the signal was super blown out. Connecting the scope showed the video signal had a peak to peak voltage of almost 3 volts! (This is way too hot for NTSC which should be closer to 1v P2P) There is also pretty ugly ghosting due to ringing, likely created inside the monitor as it's not really designed to handle such a hot signal.
I sketched out the video output circuit, which uses a NPN transistor as a simple buffer for the video signal. The people who made this card used a 75 ohm resistor in-line with the output, which might seem right for video termination with paired with the 75 ohm to ground inside the monitor, but this isn't right for a 5V signal with only 100 ohms to ground. (See picture below)
To fix this problem, just remove R13 and replace it with a 220ohm resistor, which brings the video output in-line with what it should be and makes the monitor much happier. Unfortunately, the marking R13 is impossible to read with the resistors in place, so looking at the front of the board, go to the top right corner below the 10 pin header connector. You will see a bank of 5 resistors just to the right of the DIP switches. R13 is the resistor one over from the right edge of the board.
That simple fix removes the ghosting and makes the levels roughly the same as the IIe's built in video! Easy fix for an awesome video output!
One other small caveat, the video is shifted over to the left on the Enhancer IIe versus the IIe's built in video output. I personally feel the Apple IIe and IIc video is shifted too far to the right versus other 8-bit computers... I assume there is some delay somewhere in the circuit on the motherboard causing this, and I'm not sure if this was by design by Apple. Even though the Enhancer IIe is using the provided sync and serial video stream from the motherboard, compared to the motherboard video, it looks shifted over. (You can see this in the photos on the next post.)
Anyway I hope this info was helpful! The Enhancer IIc composite output (if it has it) may also have same issue with the video being too hot. The resistor fix would help there too.
Thanks to BigSteve for giving me this card after finding it at at a recent. When I was a kid with my Apple IIc I would have been over the moon to have the Enhancer IIc! I remember seeing it in magazine ads and lusting over it, but it was far too out of my price range, especially as I didn't have a Digital RGB monitor anyway.
--Adrian
