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Atari 130XE Capacitor Replacement Guide

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Atari 130XE

This is the electrolytic capacitor list for the Atari 130XE and the recapping procedure for the Atari XE line. The 65XE, 800XE and XE Game System guides list their own capacitors and refer here for the procedure.

Values, voltage ratings, Atari part numbers and positions are from Atari's parts list and schematic for the 130XE.[1] The board variants, the power brick and the disassembly are from a 2016 reproduction of Atari's field service manual,[2] and both are cross-checked against Sams' service data for the machine.[3]

The supply you are filtering

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The 130XE has no transformer, rectifier or regulator on the main board. It takes +5 V DC from an external supply; the board carries the power socket, the power switch and filtering.[2] Atari's supply for the XL and XE machines is part C061982, 5 V DC at 1.5 A.[1][4] On the board the switched +5 V is distributed as +5A, +5B and +5C.[2]

The power socket is a 7-pin DIN, Atari part C061838, designated J7.[1]

Atari XL/XE power socket J7 (7-pin DIN)
Pin Function
1, 4, 6 +5 V
3, 5, 7 Ground
2 Shield

Every pin is +5 V, ground or shield.[4][2]

Inside the power brick

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The manual reproduction draws the external supply as follows (figure 1-11):[2]

XE external power supply (manual reproduction, figure 1-11)
Designator Part Notes
F1 Fuse Mains side
T1 Transformer 115 V or 230 V AC primary, 9 V AC secondary
D1 Bridge rectifier
C1 4700 µF Across the rectifier output
U1 LM78S05 5 V regulator
C2 100 µF Regulator output

It gives the output as 5 V ±5 % (1.5 A maximum).[2] Atari's parts list gives the supply only as a single part, C061982, and neither it nor the reproduction gives voltage ratings for C1 and C2.[1]

Capacitor list

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Atari's parts list has four electrolytic types on the board. Everything else is a ceramic part: 1000 pF (C014181-01), 0.01 µF (C014181-02), 0.1 µF (C014181-03), 0.047 µF (C014180-09), 220 pF, 68 pF, 56 pF, 22 pF, 18 pF and 10 pF, and a set of 1000 pF radial ceramics at C301–C310.[1]

Atari 130XE electrolytic capacitors (Atari parts list, 25 June 1985)
Designators Value Rating Type Atari part number
C1 470 µF 10 V Electrolytic, radial C014368
C2, C3, C10, C79 22 µF 16 V Electrolytic, axial C014393
C24, C50, C98 10 µF 16 V Electrolytic, radial C014392
C19, C20, C22 4.7 µF 35 V Non-polarised C061647

That is eleven parts. On Atari's schematic, C1 (470 µF) and C2 are across the +5 V from the power switch S1, feeding the +5A rail; C3 filters the +5B rail and C10 the +5C rail; C79 decouples the +5 V/ready line to SIO pin 10; C50 is on the +5A feed to the video buffer U20 (CD4050); C19, C20, C22 and C24 are in the audio circuit around the LM358 (U1); and C98 is on the +5 V feed to the controller jacks.[1]

C19, C20 and C22 are non-polarised electrolytics: Atari's parts list marks all three "NONPOLARIZED", and Atari's schematic marks them with an asterisk, noted as non-polarised.[1] Replace them with bipolar parts, not ordinary polarised electrolytics. Sams also lists the three 4.7 µF 35 V non-polarised parts. Its troubleshooting section names C22 when the expansion connector's audio input is silent and C19 when the SIO audio input (pin 11) is silent, and its service check for a dead machine is to measure 5.0 V at the positive end of C2, the same C2 as in Atari's list.[3]

Board variants

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130XE board assemblies (manual reproduction, figures 2-1 to 2-6)
Assembly RAM Notes
CO70065 / CO70067 16 × 4164 (64K × 1) at U9–U16 and U26–U33 The original 130XE board
CO70050 16 × 4164 SECAM. The video encoder differs, and C42, C44, C51, C52, C56, C57, C58, C61 and C69 do not have their PAL/NTSC values. The electrolytics differ too: the SECAM drawing has a second 470 µF electrolytic at C14 (a 1 nF ceramic on the other boards), on a separately filtered supply, and no C50. Work from the SECAM schematic, not from this list, on a SECAM machine[2]
CA200519 / C103579-001 4 × 4464 (64K × 4): U9, U10, U11 and a fourth that the reproduction labels U2 (U8 is the 6502C) Cost-reduced board, same electrolytic list as CO70067

The CA200519 artwork is shared with the 64 KB machines: the 65XE and 800XE use the same assembly number with only two RAM devices fitted and the second-bank decoder left out.[2]

The RF modulator

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The modulator A1 (Atari C070000) is a sealed can, listed as a single part.[1] Its output is specified as 1–2 mV into 75 Ω, sound carrier 5.5 MHz, channel 3 at 61.25 MHz ±0.5 MHz or channel 2 at 55.25 MHz.[2] The 5.5 MHz sound spacing is the PAL figure; channels 2 and 3 are NTSC channels, and Atari's NTSC 800XL manual gives 4.5 MHz.[5] Neither Atari's parts list nor the manual reproduction lists the parts inside it. The two board capacitors feeding it, C204 and C205, are 0.1 µF ceramics.[1] If the RF picture is poor, try the monitor socket, which does not go through the modulator.

Before you begin

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  • Temperature-controlled soldering iron, desoldering braid or pump, 63/37 solder, 99 % isopropyl alcohol and a multimeter. See Recommended Tools.
  • 105 °C aluminium electrolytics of the same capacitance and an equal or higher voltage rating, and bipolar parts for C19, C20 and C22.

See Capacitor Failure Symptoms for what a failing part looks like, and Battery Explosion, Capacitor or Corrosion Damage if electrolyte has reached the board.

Disassembly

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This is the sequence in the manual reproduction; Sams gives the same steps.[2][3]

  1. Turn the console upside down and remove the four screws holding the bottom cover to the top cover.
  2. Turn it right side up and lift off the top cover.
  3. Carefully disconnect the keyboard cable.
  4. Remove the seven screws holding the shielded board, and lift the assembly out of the bottom cover.
  5. Unbend the seven shield tabs and separate the top and bottom shields, taking care not to damage the board.

Reassemble in reverse: align the tabs, seat the board on the bottom shield, fit the top shield keeping the adjustment holes clear, bend the tabs, fit the assembly into the bottom cover with the locating stakes in their holes, fit the seven screws and the keyboard, then the top cover and its four screws.[2]

Replacement procedure

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Measure before replacing anything. Sams' check for a machine that will not start begins with the power pack and a short across J7, then 5.0 V at the positive end of C2 (see Verifying the result).[3] On his Atari Projects site Jason Moore reports that the original electrolytics in Atari 8-bit computers do not fail often, though some do; replace the parts that measure or look bad.[6]

  1. Photograph the board and note the polarity band of every polarised part against the board marking before removing anything.
  2. Desolder one lead at a time with a hot iron applied briefly.
  3. Clear the holes, clean with isopropyl alcohol, and check for lifted pads.
  4. Fit each new part with its positive lead to the pad marked "+". C19, C20 and C22 are non-polarised and fit either way round. Where a radial part replaces an axial one, dress the leads so the body sits where the original did and cannot touch the shield.
  5. Inspect every joint under magnification.

Verifying the result

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  1. Unpowered and unplugged, check for a short between +5 V and ground. Sams makes this a gate: if the power pack has failed, check for a short between pins 3 and 1 of J7 with S1 on, and do not fit a new power pack until the short is repaired.[3]
  2. With the pack unplugged, measure 5.0 V between pins 3 and 1 of its plug. With it connected and the machine on, measure 5.0 V at the positive end of C2.[3] The reproduction gives the supply as 5 V ±5 %, so 4.75–5.25 V.[2]
  3. Check the supply pins of the CPU, ANTIC, GTIA and POKEY; see Atari 130XE Troubleshooting Guide#Supply pins.
  4. Run the self test: hold OPTION while switching on, with no cartridge and no powered disk drive, or type BYE at the BASIC prompt. Run the Memory, Audio Visual and Keyboard tests and exit with SYSTEM RESET.[3][4] The reproduction's instruction to press HELP at a power-on logo is the 1200XL's method; the XE has no logo screen.
  5. If the picture has lost colour, the colour control is R38, a 500 kΩ preset (Atari C023030-04), reachable through a hole in the bottom cover. Sams' method is to adjust it for a blue screen.[3][1]
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References

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  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 Atari (U.S.) Corp., 130XE Parts List, 25 June 1985, pages 1–4, bound in Atari's 130XE Reference Manual (cover dated March 1990) with the Atari (Japan) Corporation schematic diagram C070065 Rev. B (130XE NTSC/PAL). Hosted on this wiki as Atari 130XE Parts List and Production Test Instructions (PDF). Source of the capacitor values, voltage ratings and types, the Atari part numbers, the 7-pin DIN power socket (J7, C061838), the RF modulator part number, and (from the schematic) where each electrolytic sits.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 130XE Personal Computer Field Service Manual, reproduction by JER/Eightbitter (PDF author "Jurek"), November 2016, with schematics and silkscreens for seven XE board assemblies redrawn in May 2014. Not an Atari publication. Section 1 (power supply description, external supply schematic figure 1-11, RF modulator specification), section 2 (schematics), section 4 (disassembly). Hosted on this wiki as Atari 130XE Field Service Manual (PDF).
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Howard W. Sams & Co., Sams COMPUTERFACTS CC16, Atari Model 130XE, service checks (p. IV), disassembly and adjustments (p. V), troubleshooting (pp. 9–10, including the self test), parts list. Hosted on this wiki as Sams Computerfacts Atari 130XE (PDF). Measured independently of Atari on a production machine.
  4. ↑ 4.0 4.1 4.2 Michael Current (ed.), Atari 8-Bit Computers: Frequently Asked Questions, last modified 29 November 2009, section 1.16 (power socket pinout) and the power supply list. Text at faqs.org. Community reference.
  5. ↑ Atari, Inc., 800XL Computer Field Service Manual, FD100740 Rev. 01, February 1984, p. 1-10 (RF modulator: audio sound carrier frequency 4.5 MHz; channel 2 video carrier 55.25 MHz, channel 3 61.25 MHz). Hosted here as Atari 800XL Computer Field Service Manual.
  6. ↑ Jason H. Moore, "Replace Faulty Capacitors on Your Atari 8-Bit Computer Circuit Board", Atari Projects, 6 October 2024: the capacitors in 1970s and early-1980s Atari 8-bit computers "don't seem to fail too often"; a discoloured C24 in an 800XL's sound circuit caused quiet sound and missing notes.


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