Editing Atari 5200 (section)

== Power ==

This is where the 4-port and 2-port machines genuinely differ, and where most surviving 5200s fail.

=== 4-port: power through the switchbox ===

The original and Universal 4-port consoles have '''no power connector of their own'''. Power and RF share one cable to the CX522 switchbox, which also contains a relay that switches the television between aerial and console.

* '''Power pack: CX521 AC/DC Power Adaptor, Atari P/N C018187. Output: 9.3 volts DC at 1.95 A.'''<ref name="fco5200">Atari, Inc., ''Atari 2600 and Atari 5200 Field Change Orders, Upgrade Bulletins and Tech Tips'': Tech Tip, model ATARI CX5200, 17 November 1982, "CX5200 Power Adaptor"; Tech Tip, model CX5200, 20 January 1983, "Defective Rockwell 6502 MPU on CX5200 PC Board"; and the CX5200 retrofit procedure for kit CA023019. Hosted here as [[Atari 2600 and 5200 Field Change Orders and Tech Tips]] ([[:File:Atari 2600 and 5200 Field Change Orders and Tech Tips.pdf|PDF]]).</ref> It is a linear supply: transformer, bridge rectifier, a 3300 µF/25 V reservoir and an MDL-5 fuse, all inside the brick.<ref name="schem5200" />
* Atari's tech tip warns explicitly: '''do not use an HCD power adaptor with the CX5200''' — it will damage both the adaptor and the switchbox.<ref name="fco5200" />
* The switchbox select switch has two positions: '''NORMAL''', which lets the console switch the television automatically when the power switch is pressed, and '''STANDBY''', which allows television viewing while the console is on.<ref name="fsm5200" />

=== 2-port ===

The 2-port console takes its own adaptor (Atari A.C. adaptor assembly CA021673) directly into the rear of the case, and uses a conventional manual switchbox.<ref name="fsm5200" />

=== Inside the console ===

Regulation is by '''two +5 V regulators, VR1 and VR2''', on a heatsink assembly (Atari CA019069). Atari's parts list gives the device as a '''78M05''' (C014348, the 500 mA part, the same regulator used in the [[Atari 2600]]); the slightly earlier schematic prints '''LM340T-5'''. Each regulator works with an '''MJE-210''' power transistor, and a '''+9 V''' rail is taken from the unregulated supply as well as the two +5 V rails.<ref name="fsm5200" /><ref name="schem5200" />

Expected readings, from Atari's diagnostic flow charts:<ref name="fsm5200" />

<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:80%;"
! Test point !! Expected !! If wrong
|-
| Core of J3 (power/RF input) || 10–12 V DC || RF cable, switchbox or power pack
|-
| Input of VR2 || +12 V ||
|-
| Output of VR2 (pin 3) || +5 V || Check for a short on the output
|-
| Pin 13 of U29 (A26), the 4013 latch || Toggles between 13 V and 0 V when the power switch S2 is pressed || Power latch fault
|-
| Pin 3 of the RF module || +5 V || L13, the RF module, or an open to VCC2
|}

=== The cartridge carries the +5 V jumper ===

The console's +5 V distribution is '''jumpered through the cartridge''': the schematic marks a link between J1 pins 36 and 18 as "jumper in plug-in ROM cartridge".<ref name="schem5200" /> A 5200 with no cartridge in the slot is therefore not fully powered. This is designed behaviour, not a fault, and it is worth knowing before you start probing a "dead" console with an empty slot.