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additional pictures

ATARI 2600 jr.
(REV.F1)
Additional pictures. Note that loading the page could take a while...
(pictures copyright by M.A.Grundke)

ATARI 2600 jr. REV.F1 serial plate (12 KBytes)

ATARI 2600 jr. REV.F1 serial plate:
ATARI 2600
PAL-B
ATARI CORPORATION
MADE IN CHINA
X73 94 007581

ATARI 2600 jr. REV.F1 board overview (68 KBytes)

ATARI 2600 jr. REV.F1 board overview:
this REV.F1-board is almost identical to the older REV.C board. First, the switches and connectors on its back (from left to right): CHANNEL 2/3 switch, left controller port, left controller difficulty switch, DC-in, right controller difficulty, right controller and RF-output. Below the RF-out the foil-connector to the machine's SELECT and RESET-buttons, and below that the RF-circuitry (including two hex inverters, a DIP16 Toshiba TC4050BP at A5 and a DIP14 LM3086N at A4, and an adjustment screw). Left from the RF-circuits, in the board's middle, resides the cartridge slot, with the UM6532 (A1), the UM6507 (A2) and the UM6526P1 (A3) below (the 2600's customchips). Moving further left, lots of parts, and among these, the POWER ON/ OFF and COLOR/ BW switches, with the power LED below. Note that the board is normally completely shielded (with the RF-circuitry having its own shielding). Note furthermore, that there seem to be no important differences to the older REV.C board. A last comment: as you can see in the lower left part of the board, there are two crystals (at Y1, Y2). That's only true for PAL-machines, because they need one for the color circuitry (like NTSC-machines, although clocked differently) and one to create the PAL color-carrier frequency. In NTSC-machines, the outlined area with the lower, additonal crystal is just unpopulated

ATARI 2600 jr. REV.F1 board info 1 (17 KBytes)

board silkscreening, part 1:
ATARI ®
© 1983

ATARI 2600 jr. REV.F1 board info 2 (22 KBytes)

board silkscreening, part 2:
CAO
REV
(both fields left blank)

ATARI 2600 jr. REV.F1 board info 3 (24 KBytes)

board silkscreening, part 3:
ATARI C021503 REV F1
(lower side of the board)

ATARI 2600 jr. REV.F1 board info 4 (18 KBytes)

board silkscreening, part 4:
PC NX 19-91
(lower side of the board - '19-91' could be the production-date: week 19 year 1991)

ATARI 2600 jr. REV.F1 CPU (30 KBytes)

The 2600 jr.'s CPU, an UMC UM6507. It's just a 6502 stripped down to 12 external address-lines (A0-A12), and lacking RDY- and NMI interrupt inputs. Note that, although the 6507's address range is 8 KBytes, it is divided into two 4K parts in the 2600-architecture (to simplify addressing: 4K for internal addresses, 4K for cartridges)

ATARI 2600 jr. REV.F1 TIA (36 KBytes)

UM6526P1 aka TIA ('Television Interface Adaptor') is the predecessor of the CTIA/ GTIA used in ATARI's XL/XE-series. They also include 6 registers used as A/D-converters. In comparison to the later XL/XE-architecture, there's no 'second CPU' (ANTIC) to control TIA's output. That has to be done by the CPU itself, effectively 'stealing' most CPU cycles. Also interesting is that, because of the different TV-standards, PAL- and NTSC-VCS are clocked different - the PAL-VCS needs a 3.5468 MHz crystal (for 312 scanlines * 228 clock counts * 50 Hz), whereas NTSC-VCS use a 3.58 MHz crystal (for 262 scanlines * 228 clock counts * 60 Hz). However, the UM6526P1 used here is the same for both TV standards (maybe even for SECAM? I don't know)

ATARI 2600 jr. REV.F1 RIOT & cartslot (56 KBytes)

The UMC UM6532 ('RIOT' or 'PIA') is responsible for the 2600's I/O-functions. It also provides a general purpose timer and 128x8 SRAM (called 'SARA', which could only be used for storing data, not code). Behind it, the 2600's cartridge slot

Also see the ATARI 2600 jr. REV.C, with its older board!

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