My 7800 research journey continues before I've even managed to start the console! I'm lacking a suitable RF monitor and hence the composite mod in the other thread that I'm waiting on before I can even see if it works.

I wanted to purchase a multi cart solution and this is where the architecture of the 7800 becomes interesting. To make the 7800 console backward compatible with the 2600 a TIA chip as used in a 2600 has been used to provide that compatibility but sadly, also limites the the sound for 7800 games to the 2600 sound. The idea Atari had was games that wanted enhanced sound could add a Pokey chip to the game cartridge but this of course comes at a cost for the games developer and only 2 original games (as far as I can find) included a Pokey onboard 
in the game cart - Ballblazer and Commando. A few homebrew games have since used Pokey or Hokey chips to unlock enhanced sound. Hokey is a modern replacement for the Pokey that is no longer being manufactured. 

List of sound chips - Wikipedia

I managed to find a Concerto Plus cartridge that has a Hokey onboard and seems to provide a wealth of other enhancements. Ordered and is on its way from the US to the UK. Let's see how quick that will be but could find any locally.

Concerto - 8BitDev.org - Atari 7800 Development Wiki

I'll report back once I've managed to get this all together.

Mark

I recently purchased a 7800 via eBay after being successful with a cheeky bid. I've never had or used one but always interested in the concept and have had many other ataris over the years from a 2600, 8bit computers and a few ST's.

Over the coming weeks I will be modifying the console to allow me to use on a modern TV, look at what repairs, if any are needed and look for a multi cart that addresses the pokey challenges of a couple of cart having pokey chips installed.

I haven't decided if I should video the progress or just document with some photos, let me know what you'd like to see?

Cheers
Mark

   

Technical Bulletin TN002.1

Date 29 January 1986

Aset of 6 ROMS. These ROMS are identified as follows:
PART NUMBER

C026160-001 U2
C026244-001 U3
C026245-001 U4
C026163-001 U5
C026246-001 U6
C026247-001 U7

See PDF for  schematics and fault finding information including hand written notes.

Attached Files

  TN002-1.PDF (Size: 1.42 MB / Downloads: 2)

Technical Bulletin TN002

Subject: TOS ROM UPGRADE
This document should accompany a set of 6 ROMS. These ROMS are identified as follows:
PART NUMBER    LOCATION

C026160-001  U2
C026244-001  U3
C026245-001  U4
C026163-001  U5
C026246-001  U6
C026247-001  U7

See PDF for additional topics such as:
Upgrading Colour Systems (Glue chip versions)
Further ROM information such as Boot EPROM and version before masked roms were available.
Hand drawn schematics 
...

Attached Files

  TN002.PDF (Size: 4.7 MB / Downloads: 4)

Technical Bulletin TN001

Date: 7 January 1986

Subject: 520ST RGB Output
Early models of the 520ST support seperate VSYNC (pin 12) and HSYNC (pin 9) for RGB.

The Thomson colour monitor CM36382 AR requires a combined SYNC input on (pin 20 of the SCART connector). 520ST's manufactured after Nov 85 have been modified to provide combined SYNC on pin 2 of the DIN connector.

These  modified  520ST's can be identified  by their serial number, as it should start with a 4.

The modification to the 520ST is as follows:
All components should be mounted on component side of PCB in area reserved for UHF modulator.

See PDF for schematic

Attached Files

  TN001.PDF (Size: 399.6 KB / Downloads: 1)

A letter to the dealers from Les Player n the introduction of Technical Bulletins including TN002

1 May 1986
Dear Dealer 
I would like to introduce to you the first batch of Technical Bulletins.  These will be presented
to you on a monthly basis, included in  the Atari monthly News Bulletin.  The object of the
Technical Bulletin is  to pass onto you technical information that we feel  will help you sell and
support Atari Products.  The Technical Bulletin will contain bath hardware and software
information.

I would also like to introduce you to the Atari Technical Support Team.

Software Support - Robert Katz
Hardware/Service Support  - Knolly Shadrache/Philip Wong Victoria Everitt
General Technical Information - Victoria Everitt
Customer Relations - Lucinda Bell


We would be grateful if you would avoid passing these names to end Users as we are all here
principally for Dealer Support. End User overload results in less capacity to help you.

Should you have any questions please do not hesitate to contact us. Yours sincerely

LesPlayer
Technical Manager

Technical Note: TN002
Subject: TOS ROM UPGRADE

This document should accompany a set of 6 ROMS. These ROMS are identified as follows:
PART NUMBER

C026160-001 U2
C026244-001 U3
C026245-001 U4
C026163-001 U5
C026246-001 U6
C026247-001 U7

These ROMS should be handled with caution.
Before starting an upgrade, ensure that the 520ST is fully operational, then remove all power, video and disc cables.


UPGRADING COLOUR SYSTEMS

Some colour monitors will not have enough adjustment on their vertical and horizontal adjustments to centre the screen.  The GLUE IC C025915-38 will now compensate for this.  If you do not have this version then you will also need to upgrade your GLUE IC:

There are three versions of the GLUE chip:
Version 
1: C025915
2: C025915-20
3: C025915-38

.....

Attached Files

  TN002.PDF (Size: 2.64 MB / Downloads: 2)

Not sure if these are still useful to anyone...

Date: 16 June 1986

Atari XC12 Program Recorder Torque numbers when new:

PLAY 52 g/cm
REWIND 110 g/cm
WIND FF 84 g/cm

100 Second count with 800XL 98 seconds.

Attached Files

  XC12.PDF (Size: 1.1 MB / Downloads: 1)
  Recorder Manual.PDF (Size: 1.07 MB / Downloads: 1)

Technical Bulletin TN009

Date@ 21 April 1986

Re: Current Approved Disc Media


Atari currently recommends the use of the following disc media:-
3 1/2" Single Sided Double Density
Dysan 
Sony 
Fuji
Kasei - Verbatim 
Konishiroku

3 1/2" Double Sided Double Density
Sony
Konishiroku

Attached Files

  TN009.pdf (Size: 242 KB / Downloads: 1)

Technical Bulletin TN008

Date: 17 April 1986

Re: STM UHF Modulator Adjustment

The UHF TV output may not appear central on some TV sets, slight modulator adjustment should
correct inconsistent positioning.
Proceed as follows:-
1.    Only Qualified service personnel should attempt to carry out the following procedure on the
520STFM and 1040STFM as mains voltage exists within these models.

2.  Remove plastic cover and R.F. shield
3.  Remove modulator shield
4.  Apply power and adjust the plastic cross head screw on the modulator PCB until the display is
central.
5.  Replace shields and all screws.

As well as producing a modulated output, the STM also provides an un-modulated composite colour
output on pin 2 of its 13-pin Din socket which connects to pin 20 of the Atari Scart Connector.

Attached Files

  TN008.pdf (Size: 361.88 KB / Downloads: 1)