some years ago I gave a promise to an ABBUC member to make a video-out solution for his Atari 400 without the need of changing parts, scratching conducting paths or any other destructive mod to his Atari 400. He´s a real "hardcore" collector with no way in give-and-take regarding this point.
After tinkering around with an "add-on" PCB for the GTIA socket I failed, because there´s not enough space. Of course - from a collector´s view - it´s a No-Go to remove the metal cabinet, so I decide to create a complete new CPU board with the needed components directly on it.
I´ve reached the goal by 99%. A very little bit of soldering is required and the need to drill one hole into the metal assembly - the shielded video cable needs a place to break out, there´s no way else than making a new 5 mm hole somehwere in the upper part of the metal assembly.
So here´s my solution: The Super Color CPU Card for Atari 400 and Atari 800 systems
This PCB is a complete replacement for the original CPU card in any Atari 400 or 800 using PAL or NTSC. This PCB works NOT with SECAM. You are able to use both CPU-types found in the Atari 400 and Atari 800 series, the standard 6502B MOS CPU (without HALT signal) and the Atari-specialized version 6502C, also called "Sally". Chips (CPU, ANTIC and CTIA or GTIA) are not included and must be pulled of the built-in Atari CPU card. But they are always in sockets, so it´s easy.
Circuitry on this PCB is nearly 100% the same like at the genuine Atari CPU card with some changes to make it possible to use both CPU types. You only need to set five jumpers to select the desired CPU type. Addiitonal the PAL color clock generation circuit is onboard for PAL systems. There´s a seperate jumper to select PAL or NTSC - this jumper connects the GTIA "PALC" pin to either the output of the PAL color clock generator or directly to 3,57 MHz system clock (NTSC). Only for clarifying this: You can´t just switch the jumper and make a NTSC system to a PAL computer or vice versa. At least you´ve to change ANTIC, GTIA and of course the system clock crystal at the mainboard
At least a third jumper block (not existing an the prototype shown on the picture above) enables/disables the 75 Ohm termination resistors for Luma, Chrominance or CVBS output. This setting must be tested depending on the connected monitor or television - sometimes the picture quality is better with, sometimes without termination resistors.
The video out solution is based on the Atari 800 XL video circuitry without mixing Luma and Chroma together. Of course the well-known mods are already integrated. The final signals are amplified and filtered by the Fairchild FMS6410 VideoAmp. This chip also generates the CVBS signal. So you can use either S-Video (Y/C) for best picture quality or CVBS for common monitors and televisions which doesn´t accept S-Video (Y/C) input.
Please notice: This video solution can´t performing magic. I test it on different computer monitors and televisions. The best performance - as ever in every setting with old computers - will be shown on CRT (tube) monitors or televisions. Of course for Atari 400 owners EVERYTHING is better than the antenna (RF) output, but don´t expect a higher quality than the regular Atari 800 S-video output. It might be better, but I can´t promise. That´s impossible by the dozens of different monitors, cables, T.V. systems and so on.
Scope of delivery
- One PCB "Super Color CPU Card" for Atari 400 or Atari 800 computers, capable using 6502B or 6502C CPU, runs on PAL or NTSC systems
- A manual (illustrated installation instructions) in german and english (sent by email with shipping out notice)
- One DIN connector 5 pin to lead out the video signals (optional for Atari 800 users)
- approx 50 cm shielded cable for video out
- approx 50 cm shielded cable for internal audio connection (optional for Atari 800 users)
I offer two versions of the PCB
- "Standard" = Full populated (except Atari custom chips) PCB, standard HASL surface (as shown in the picture above)
- "Gold" = Full populated (except Atari custom chips) PCB, gold-finished (ENIG) surface (like my Sys-Check and many other solutions)
The ENIG (gold-finished) surface is more rugged against rust and fouling. Because the naked PCB price doubles when choosing ENIG at this board size, I offer two versions.
- One "Standard" PCB = 48 Euros each
- One "Gold" PCB = 59 Euros each
- Registered and insured shipping 1 or 2 piece(s) worldwide = 9 Euros
- Registered and insured shipping 3 or 4 pieces worldwide = 12 Euros
- More than 4 pieces or specialized = please ask
Info: After some bad experiences with some postal services I only ship insured now.
- I will collect orders and payments until the end of January, the 22.th 2017 (GMT)
- At the end of January I will order the parts and PCBs
- Assembling and shipping out can take up to 6 weeks, because there´s no holidays for me, assembling will be done in my spare time
- Depending on shipping time you will get your PCB(s) in March or April 2017 - This is the worst case, but I won´t promise things I can´t realize. So this is a safe suggestion.
- First payment, first serve: I can´t make all PCBs at one time, so small batches will be made. Date & Time of cleared payment sets the order of shipping out
Please sent me a PM (personal message) or leave a post in this thread. You will get an answer soon.
Practical hints for Atari 400 users
The Atari 400 hasn´t any S-Video/CVBS output and no standard monitor jack, just an antenna (RF) cable. This cable is replaceable, so the best way is to remove the whole cable. You can use the hole in the case where the antenna cable was now for the new video out cable. At the end a standard DIN 5 pin connector coupling is applied. You can use ANY standard CVBS or S-Video cable made for any Atari XL or XE (or the Atari 800) to connect your Atari 400 to a monitor or television. The sound signal must be clamped from the main PCB. Nothing is destructive, only two solder drops at the mainboard of your Atari 400 must be made and one hole with ~5 mm diameter must be drilled in the metal cage for leading the video cable out.
Practical hints for Atari 800 users
Remark: The Atari 800 has already a quite good video output (S-Video). The CVBS output ranges something in the middle of existing video solutions. The need of my Super Color CPU card isn´t really mandatory for an Atari 800 owner, but it CAN improve video quality. Of course without any promises. I repeat that to make this point of view clear for all interests.
The first option is to go ahead like the Atari 400 user. Replace the antenna cable with the new video cable. The existing monitor connector is always out of function when replacing the Atari CPU card with my Super Color CPU Card.
Second option for Atari 800 users is to use the existing monitor jack with the new Chroma, Luma and CVBS signal. For this purpose the best way is to bend away the three connections from the mainboard to the power-PCB transmitting these three signals. This is reversible, non-destructive and needs only four additional drops of solder at the monitor jack.
The manual will show how to do and also point at the junctions where to grab the audio signal, too. If you want, the external monitor DIN 5 pin coupling connector is already soldered. Leave your wish with your order, otherwise I will ask when confiming your payment.
Any questions? Feel free to ask
Edited by tf_hh, Tue Jan 3, 2017 10:37 AM.