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Philips CDI 470 General Maintenance

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Philips CDI 470 exploded view (service manual)
Exploded view of the CDI 470 with Philips's (de)mounting flowchart (service manual, section 4.1)

The parts of the Philips CDI 470 that need attention with age are the timekeeper NVRAM chip, the disc mechanism and the supply rails, including the -5 V fuse on the main panel.[1][2][3] Unlike the top-loading Philips CDI 450, it has its power supply inside the case. Fault-finding is on the Philips CDI 470 Troubleshooting Guide and the capacitor list on the Philips CDI 470 Capacitor Replacement Guide.

Safety

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The 20PS304 supply inside the CDI 470 runs from the mains. Its main board has the primary side outlined and marked "LIVE PART", including the 100 µF 400 V reservoir capacitor 2103; the small mains board carries the inlet, the fuse 1101 and the X capacitor 2101.[4][5] Retrostuff advises unplugging the mains lead and leaving the power switch on for some time before opening a CD-i supply, and treating the large filter capacitors as a shock risk until they have discharged. Measure across 2103 before touching the primary side.[6]

The player is a Class 1 laser product; do not look into the lens with the mechanism running.[7][1] Philips's service manual covers SMD and ESD handling in section 3.[8]

Opening the player

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Philips's flowchart gives the order and the screw positions. The letters are those on the exploded view.[9]

  1. Remove the cover (k): seven screws, 171 to 178.
  2. The parts under the cover can then be removed separately: the front (a, three screws 75 to 77), the loader (d, three screws 200, 202, 203), the inlet panel (e, three screws 280 to 282), the wiring guide, and the main panel with the text plate (h, four screws 217, 218, 268, 269).
  3. With the front off, remove the bracket (b, two screws 30 and 31) to reach input port 1, the display panel (c, two screws 22 and 23) and the power knob.
  4. With the inlet panel off, remove the guiding support (f, three screws 196, 211, 212), then the spring and the guide.
  5. With the wiring guide off, remove the power supply panel (g, one screw 219).

Photograph the wiring before unplugging anything. Retrostuff found it simplest to free the CDM 12.1 by pushing its four rubber suspensions through their holes, after noting the cable routing.[1]

Disc mechanism

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The CDI 470 uses the CDM 12.1, Philips service code 4822 691 30278; the cover of the service manual says the same CDM is used in the CDI 450.[7] Retrostuff repaired a CDI 470/20 whose discs would not spin; the Service Shell's motor test reported MOTOR ERROR. Lifting the turntable back up its shaft with a flat tool cured it.[1] Afterwards it greased the gears and the metal rod the sledge runs on and spread the grease with SLEDGE OUT and SLEDGE IN in the Service Shell, pressing each only once at a time so that the sledge does not run past its end stops.[1]

Philips's VAM 1202 is the official replacement for the CDM 12.1. It comes without the four rubber suspensions and the six wires, which have to be moved over from the old mechanism.[1] The top-loading version of the same mechanism, the CDM 12.1T, is covered in more detail on the CDI 450 maintenance page; retrostuff says its sledge guide also applies in part to tray-loading players with the CDM 12.1, VAM 1201 or VAM 1202, apart from the wire routing and the suspensions.[10]

NVRAM timekeeper

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The CDI 470's settings, saved games and clock are held in an M48T08-150PC1 timekeeper at position 7241.[11] Its internal BR1225 cell runs down once the clock has been started; a failing chip loses data and the date, and can stop the player at a light blue screen or the "memory full" error.[2] Replacements are the M48T08-150PC1, still made, and the out-of-production Dallas DS1643. Retrostuff warns against "new" timekeepers from eBay or AliExpress.[2]

Desolder the old chip with fresh solder, plenty of flux and a desoldering gun; some pins are soldered on both sides. Retrostuff fits a standard 28-pin socket so that the next replacement is easy.[2] Check every socket joint afterwards: its CDI 470 kept giving the memory full error until it found that pin 11 (D8NVR) had no proper connection to the board, and fixed it for good with a short wire to the next test point.[1]

The circuit diagram draws 7241 as "8kx8 OR 32kx8": resistor 3241 is fitted only for 8 KB, and 3242, 3244 and 3270 only for 32 KB.[12] Retrostuff upgraded a CDI 470 to 32 KB by changing those jumpers and fitting a CDI 490 system ROM, which detects the NVRAM size by itself; patching the 470's own ROM caused clock faults and corrupted saved files.[13]

Calibrating the clock

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Item 7 of the Low Level Test trims the timekeeper to within one minute a month and needs a frequency counter with a gate time of at least 5 seconds. Measure on pin 23 of the PAL20L8 at IC 7272 (CSCIAPN), where the reading should be near 512 Hz, between 511.96724 and 512.03276 Hz, then type the measured value into the terminal. Do not run this item unless calibration is needed; if it is entered by mistake, switch off and restart the test.[14] The step also says not to disturb pin 25 of IC 7310, a line carried over from the CDI 450 manual: in the CDI 470, 7310 is a BC848B and the CIAP is 7331.[14][11]

Supply and fuses

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CDI 470 fuses
Position Part Where Protects
1101 T 1 A L 250 V Mains board of the 20PS304 Mains input
3255 MP100 (4822 252 51173, 65 V 1.0 A) Main panel, beside the supply connector, grid F1 -5 V rail
3277 RXE065 polyswitch, 1 Ω Main panel +5 V feed to the input ports and RF modulator (+5VF)

[4][3][12]

The 20PS304 has no fuses on its own outputs.[6] Retrostuff found its CDI 470's 3255 open after a probe slipped and shorted +5 V to -5 V on the extension connector; it recommends a fly lead on pins A1, B1 and C1 of that connector for safe measurements.[3] The US version of the supply has a 10 MΩ resistor, 3102, from neutral to ground, marked for UL/CSA versions only.[4][6]

Preventive maintenance checklist

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  1. Check the date and time in the player settings; a lost date points to the timekeeper.[2]
  2. Run the Service Shell CD drive test with an audio CD (modes 0 to 3).[15]
  3. Check +5 V and -5 V at the main panel, as on the troubleshooting guide.[16]
  4. Look at the electrolytic capacitors in the supply for bulging or leakage; see Capacitor Failure Symptoms.
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References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Retrostuff, "Philips CDI470 Diagnosis and Repair", 23 December 2019 (retrieved 2026-10-20): memory full error traced to pin 11 (D8NVR) of the NVRAM socket; Service Shell CD drive tests; MOTOR ERROR cured by lifting the turntable; removing the CDM 12.1 by its four rubber suspensions; greasing; VAM 1202 as the official substitute, without suspensions and wires.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Retrostuff, "NVRAM+RTC Solutions for Philips CD-i Players", 2021, updated 2025 (retrieved 2026-10-20): 8 KB timekeepers in most CDI 470s, the BR1225 cell, failure symptoms, removal, sockets and replacements.
  3. ↑ 3.0 3.1 3.2 Retrostuff, "Philips CD-i Mono III / IV Fuses", 2021, updated 2024 (retrieved 2026-10-20): fuse 3255 MP100 (65 V 1.0 A) on the -5 V rail of the CDI 470 and 490 at grid F1; the short on the extension connector; the resettable fuse on Mono IV boards is an RXE065; measuring on extension connector pins A1, B1 and C1.
  4. ↑ 4.0 4.1 4.2 Philips, CDI 470 service manual, section 7.4 Power supply (PCS 85 619 and 85 620): mains print with fuse 1101 (T 1A L 250V) and resistor 3102 (10 MΩ, "Use only in UL/CSA Version"); main supply board with its "LIVE PART" area. Hosted as File:Philips CDI 470 Service Manual.pdf.
  5. ↑ Philips, CDI 470 service manual, section 8.4 Partslist of the Mains Supply panel (PCS 85 633): 2101 330n 250V, 2103 100µ 400V. Hosted as File:Philips CDI 470 Service Manual.pdf.
  6. ↑ 6.0 6.1 6.2 Retrostuff, "Philips CD-i Power Supply Units", 2024, updated 2026 (retrieved 2026-10-20): safety warning; 20PS304 with no fuses on the supply boards apart from 1101; US version with resistor 3102.
  7. ↑ 7.0 7.1 Philips Service & Support, Philips Media Systems, Compact disc interactive player CDI 470/00/05/06 service manual, P.S. 0795, 4822 725 24768, cover (PCS 85 601): CDM12.1 service code 4822 691 30278, "This CDM is also used in CDI450"; Class 1 laser product. Hosted as File:Philips CDI 470 Service Manual.pdf.
  8. ↑ Philips, CDI 470 service manual, sections 3.1 to 3.3 (PCS 85 606 to 85 607): safety instructions, servicing SMDs and handling ESD-sensitive components. Hosted as File:Philips CDI 470 Service Manual.pdf.
  9. ↑ Philips, CDI 470 service manual, section 4.1 Exploded view of the cabinet, (de)mounting flowchart (PCS 85 609). Hosted as File:Philips CDI 470 Service Manual.pdf.
  10. ↑ Retrostuff, "Philips CDM 12.1T Laser Sledge Replacement", 27 July 2021 (retrieved 2026-10-20): the guide is partly valid for tray-loading players with CDM 12.1, VAM 1201 or VAM 1202, apart from wire routing and suspensions.
  11. ↑ 11.0 11.1 Philips, CDI 470 service manual, section 8.2 Partslist of the mainboard (PCS 85 632): 7241 m48T08-150PC1, 7310 BC848B, 7331 CIAP1.5. Hosted as File:Philips CDI 470 Service Manual.pdf.
  12. ↑ 12.0 12.1 Philips, CDI 470 service manual, section 7.5.3 µP part circuit diagram (PCS 85 622): NVRAM 7241 "8kx8 OR 32kx8" with option resistors 3241, 3242, 3244 and 3270; fuse 3255 MP100 on -5 V; PTC 3277 RXE065 1R on +5VF. Hosted as File:Philips CDI 470 Service Manual.pdf.
  13. ↑ Retrostuff, "Philips CDI470 32 KB NVRAM Upgrade", 29 December 2019 (retrieved 2026-10-20): 8/32 KB jumper switch, ROM tests; the CDI 490 ROM as the best choice; patched 470 ROMs not recommended.
  14. ↑ 14.0 14.1 Philips, CDI 470 service manual, section 5.1 The Low Level Test, item 7 Clock calibration (PCS 85 610). Hosted as File:Philips CDI 470 Service Manual.pdf.
  15. ↑ Philips, CDI 470 service manual, section 5.2 The Service Shell (PCS 85 637 and 85 617). Hosted as File:Philips CDI 470 Service Manual.pdf.
  16. ↑ Philips, CDI 470 service manual, section 6.3.1.1 Test of the DC power supply voltages (PCS 85 613). Hosted as File:Philips CDI 470 Service Manual.pdf.


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