Atari 7800 Hifi Rack Version

[retromod]

I currently work on an interesting project: A customer ordered an Atari 7800 in a hifi rack housing.

We finally agreed to include an AV+, Stereo/Surround and Pause mod (for Atari 2600 mode).
A background light in blue which can be switched off completes the design. Power supply is internally and a SCART plug including the joystick ports on the back. Pre-fitted with PSX joystick mod.

I started with a mockup how it would looks like after completion:


Picture: front view


Picture: back view

This thread will describe the progress of this project.

I first started with opening the chassis, try to find the right location for the mainboard. The mainboard requires some changes:

1. power regulator must be moved to housing (better cooling and reduction of height)
2. capacitor must be rotated else the chassis can't be closed
3. cartridge slot must be turned by 90 degree angle to the front

considerations:

1. reduce the length of critical signal pathes by moving the mainboard to the right position.
2. power supply will be added without modification which could be critical due to regulations and insurance
3. the chassis must be modified without adding cracks or scratches (the black painting is quite sensible)
4. the keys must be identical to the already builtin ones

A visit at my local dealer provided the right material. I finally choose silver function keys which are altered by painting to the right color match.

Metal stripes are used to create the function key and connector panel out of it. It is then colored in black with several levels of painting. The pictures below illustrate how the front was created. If you have the right tools all visions comes true 

[retromod]

Yesterday I completed the back and front panel.


Picture: Front


Picture: Back

As you can see the mainboard is seated but not fixed yet. The power supply part is completed but requires cabling. The front and back panels are fixed and ready for soldering. The expansion slot for the PSX mod is ready (currently unsoldered).

The cartridge slot is still missing together with the mods and mainboard modifications. These are the next points on my list.

[zapiy]

That's a very clever way of housing this.

[Shadowrunner]

Yeah that's pretty cool, looks just like a stereo component from around that time period.

[zapiy]

Must be a high cost to that one?

[retromod]

Must be a high cost to that one?

The hifi-rack was about 95 Eur. The 7800 mainboard including all mods, cables, parts and working time is about 200 Eur.  Finally you have a unique device, best video and audio currently available. The pause mod is unique as well as this mod is only available in my shop. It is pre-fitted with an expansion port for the upcoming PSX controllers which adds additional value to this system (as you are able to control all from a single PSX controller)



 

[zapiy]

Have you ever thought of expanding to other systems? ie not just Atari.

[retromod]

Yesterday I added the 7800 mainboard to the chassis, implemented the mod board for video/pause and have done some video calibration. The internal power supply was connected and the function keys soldered. I replaced the front led's with blue (power) and yellow (pause).

Modified the mainboard:
- removed LED, power connector
- prepared the board for the stereo/surround mod
- rotated some components by 90 degree (else the top won't fit)

I noticed some video interference due to the power supply which is now combined with the board in one metal shield. This must be addressed by adding some additional filters to the power circuit of the board.

Open items:
1. cartridge slot (housing and 90 degree rotation)
2. filter components for power supply
3. implement stereo/surround mod board and connect them to the function key
4. burn AV+/pause firmware
5. connect joystick ports and SCART adapter
6. cable expansion slot for PSX mod
7. backlight in blue for cartridge slot, behind function keys and on left/right of chassis
8. overall function test with different games and fine tuning
9. add the silver logo and labels, create a short manual

[retromod]

Have you ever thought of expanding to other systems? ie not just Atari.

well I already mod Intellivision and Coleco Vision, Atari Homecomputers.
Currently evaluating MegaDrive and SNES for possible unique mods.

[retromod]

Yesterday I built the cartridge slot and final parts of the front.  The mainboard was also completed.

Still open is the problem with the power supply. If the housing is closed the power supply interfears the signals due to the metal housing. Currently working on a solution.

[retromod]

found a possible solution for the power supply noise problem within the housing. Made some quick tests and it looks much better after it. Time to visit my local dealer getting an additional housing. By following the EMV guidelines it is possible to reduce the amount of "noise", I will also add an additional filter circuitry.

[retromod]

Great progress here since yesterday.



Items done:
- backlight in blue now working. The right function key enabled/disabled the light on demand.
- cabling of joystick ports to the back
- cabling of cartridge slot
- pause mod modifications
- altered housing according to the VDE regulations. The power supply now has it's own shielding

Items open:
- cabling of Stereo/Surround mod
- firmware installation for the mod's
- completion of expansion port cabling
- power supply filter implementation
- SCART plug cabling (currently working with temporary composite cable)
- atari logo and plates
- final verification and testings, fine tuning of video output

[retromod]

Items done:
- cabling of Stereo/Surround mod
- SCART plug cabling
- testing of all connectors and functionality
- optimized cabling

Items open:
- firmware installation for the mod's
- completion of expansion port cabling
- power supply filter implementation
- atari logo and plates
- final verification and testings, fine tuning of video output

new pictures tomorrow.

[Greyfox]

your client must really love the 7800

[retromod]

your client must really love the 7800

actually it is more work than paid for... 

I just noticed that if I remove cartridges from the slot you might break the legs on the back if you do not remove it exactly in the right angle. So additional work is required to make them smaller to prevent such issues.

But finally it would be a great console, looking quite nice. I will provide detailed modding log in my upcoming book of course.