Atari 7800 Hifi Rack Version

[zapiy]

Great stuff and a new book?

[retromod]

Great stuff and a new book?

yes I'm currently working on a book about modding of consoles. Starting with Atari.
It will contain some modding log books as well as techniques, technical details, backgrounds and of course the next 1000 numbers winning the euro-jackpot over the next years

[retromod]

Update:
- I completed the 2600 pause mod. If pause is activated in 2600 or 7800 mode the pause LED will flash.
- I'm not very happy with the cartridge slot as some 2600 games will be difficulty to pull in/out. Seems I must do some adjustments.
- Labels are completed, must be put on front and back
- Manual started
- Stereo/Surround is working
- AV Plus is working
- power supply filter established

I played a while with the mainboard as there seems to be a sync issue with the 6502C. I resoldered some spots but sometimes it gets flacky. Hopefully I found it yet as it is stable. But it requires some additional monitoring and testing to ensure the problem is really addressed.

Pictures will follow soon.

[retromod]

Covers, Plates and manual completed.

Corrected the cartridge slot so games have now less space for adjustment and so preserve the connector inside. Previously it was in a bad angle allowing to break cartridge or slot easily.

How pause mode works:

1. Atari 7800 Mode
Works as before, push pause button to stop or continue a game. During pause the pause led flashes in yellow.

2. Atari 2600 Mode
Push pause button to stop a game. Video and audio is switched off. pause led flashes. pushing it again resume the gameplay. video and audio is activated. If a game requires the B/W switch you are able to switch into another mode by pushing the pause switch for about 10 seconds. Pause led flashes to signal mode change. Now the switch works as B/W key. This is usefull for some rare games using the switch for other features.

Stereo key activates stereo/surround sound, backlight key put the internal backlight on, console shines in blue.

Still open is the fine adjustment of sound and video. A small step until delivery to customer....

[retromod]

Fine adjustment completed, picture and sound is now on right level.
The Atari 2600 pause mod will be optimized today as I feel there is room to reduce the number of parts and simplify the circuit. This improvement will find it's way to the next revision of the PCB.

I rearranged some cables yesterday and run the first test cycles with different games. Today I will finish the pause mod and run a longer test cycle to ensure there is no issue even in stress condition or after heat up of the components.

Final pictures will follow soon.

[zapiy]

Just awesome.. Simple.

[retromod]

It seems the used board suffer from an overheating issue leading to sync failure between TIA and CPU. Most likely the RDY pin of the cpu is inside damaged. So I won a complete replacement operation for the CPU which prevents delivery to the customer.

I noticed the problem during my longterm testings. After more than one hour the video lost sync with weird video output and even a power on/off have not solved the issue. After cooling down for a few minutes it worked again, but immediately it failed with the same problem. it was reproduceable and by inspection of the involved components I noticed the RDY pin of the CPU was some kind of broken. Most likely the pre-owner of the board already noticed a flaw and tried to compensate it.

Luckily I have a spare CPU so will first implement a socket placing the cpu into it. I hope it is working and not a faulty one else I need to replace the board - which is really hard work due to all the changes.

But better finding the problem yet and not at customer side.

[retromod]

This weekend I replaced first the CPU then noticed some display issues in 2600 mode so replacing the board was required. bad but required to ensure system is properly working.

Today I start my burnin test and hopefully deliver it to customer tomorrow.

[retromod]

To find the last issue with noise in 2600 mode I replaced the mod-board with one already tested in a normal 7800 and there was nearly no improvement.

After opening the cable channel picture got immediately better. So problem is dedicated to  cabling and longer distances in the chassis. To prevent those influences I will replace the signal cables with shielded one today.

[retromod]

The remaining issue was finally a glitch in Atari 2600 video mod. This was forced by a "special" SCART connector delivered with his own PCB. After removing the PCB all works fine, picture is brilliant.

Console was delivered to customer.

Here the last pictures and videos

http://youtu.be/m_wF8Wa5eNc

[retromod]

another video will follow soon presenting the remaining functionality of the console.
long journey until completion but finally it is done 

[Shadowrunner]

Looks awesome! Your customer must be very happy with the results

[retromod]

http://youtu.be/FGRM_LNlxtY

[retromod]

Customer feedback
http://www.amibay.com/showthread.php?67915-The-quot-Knight-quot-A-Hifi-Rack-Atari-7800