Philips CDI 910 Troubleshooting Guide

Rear of a Philips CDI 910

Philips' technical training manual for the Philips CDI 910 sets out the order of fault-finding: watch the symptoms to decide which section is at fault, use the service shell to test the drive, audio and video circuits, and use the low-level test when neither the player shell nor the service shell will start. The CD servo section and the audio processing unit work like those of an ordinary Philips CD player, so the usual CD player methods apply to them. Owners' repair reports that deal with the 910 itself are scarce, so the procedures below come from Philips' documents.

Before you start

• Unplug the player and let the supply's filter capacitors discharge before touching the power supply.
• Short the CDM flex cable contacts with a conductive clip whenever the mechanism is out, to protect the laser from static.
• The tools Philips lists are a VT100 terminal or a PC running VT100 emulation (or Philips' low-level test unit), the service shell jumper plug, extension cables for the APU and the video encoder panel, and a CD-i prototype test disc.

Which section is at fault

Isolating the fault (training manual pp. 9, 21, 26–31)

Symptom	Section to check first
No sign of life	Power supply
Neither the player shell nor the service shell starts	MMC unit: run the low-level test
Picture from a CD-i disc but no sound	Audio decoding: APU and the audio path on the CD unit
Sound but no picture from the disc	Video decoding on the MMC unit
Player shell shown, but no video from the disc	Video decoding section of the MMC unit
No video on any output	Video encoder panel or MMC unit
Picture but no colour	Video encoder IC 7601 and its subcarrier
Disc does not start	Drive processor, servo circuits, X-bus to the MMC

Power supply

The supply is a self-oscillating parallel switched-mode supply with outputs of 5, 8, −8, 12, −12 and 30 V. An optocoupler (6017) feeds the 5 V regulation back to the primary side, where 7001 and 7004 switch the switching transistor 7002 off at the end of each cycle.

Testing it on the bench

1. Take the supply out of the player. The connectors to the player's circuits can be unplugged.
2. Load the 5 V output with a 5 Ω, 10 W resistor, which draws about 1 A. Without a load the overvoltage protection trips.
3. Raise the mains voltage slowly with a variac while watching the 5 V output. The supply starts with an audible squeal somewhere between 10 V and 50 V AC.

Philips' service manual for the CDI 220/00, which has the same supply design, asks for a 4 Ω, 25 W load on the +5.2 V output in its measurement section and warns never to switch the supply on without one.

Service hints

• If the fuse is open, switching transistor 7002 is probably shorted. Check 7001 and 7004 as well.
• If the supply squeals, either there is a short on its secondary side or in the player's circuits, or the overvoltage protection is active. When the protection is active, the triac 7007 runs hot; check the control circuit.

Overvoltage protection

The protection circuit watches the 5 V output and trips at 6.2 V ±0.5 V. When the voltage across 3024 exceeds 2.5 V, the programmable shunt regulator 6011 conducts and fires the triac 7007, which clamps the 30 V output to the 5 V output. The overload pulls all the secondary voltages down, and the supply squeals.

Output voltages

Philips' CDI 220/00 service manual gives the checkpoints +5.3 V on the +5.2 V output, ±12.1 V, ±8 V and +28.5 V on the 30 V output, and sets the +5.2 V output with R3020 to 5.3 V ±40 mV at test point 51. The connector pins are listed on the Philips CDI 910 General Maintenance page.

Low-level test

The low-level test lives in the boot part of the CD-RTOS ROM, needs no external RAM and reports through the UART of the 68070. It checks the VSC, ROM, NVRAM, DRAM, CDIC and slave processor. If it shows a fault, Philips replaced the MMC unit; if it cannot be started at all, check the supplies to the MMC board, and replace the MMC unit if they are all present.

1. Switch the player off.
2. Connect a VT100 terminal, or a PC with VT100 emulation, to port 2. Set 9600 baud, 8 data bits, 1 stop bit, no parity, no handshake.
3. Hold the space bar on the terminal while switching the player on.
4. The terminal shows the title of the terminal low-level test.

With Philips' low-level test unit on port 2 instead, its display shows "CDI RLxx", where xx is the release number, and the Yes, No and Test keys drive the test. The CDI 910 has only one ROM, so it skips the ROM tests in steps 2 to 4, and early production 910s may report an error in step 5, the NVRAM test.

Low-level test error codes (training manual table 2)

Code	Meaning	Code	Meaning
Er01	ROM10 in wrong position	Er12	DRAM error, banks 0 and 1, inverted data
Er02	ROM11 in wrong position	Er13	DRAM bank 0 error
Er03	ROM20 in wrong position	Er14	DRAM bank 0 error, inverted data
Er04	ROM21 in wrong position	Er15	DRAM bank 1 error
Er05	ROM10 checksum error	Er16	DRAM bank 1 error, inverted data
Er06	ROM11 checksum error	Er17	CDIC RAM error
Er07	ROM21 checksum error	Er18	CDIC RAM error, inverted data
Er08	ROM22 checksum error	Er19	CDIC register error
Er09	NVRAM error	Er20	Slave error (wrong echo from the slave)
Er10	NVRAM error, inverted data	Er21	Invalid release number from the slave
Er11	DRAM error, banks 0 and 1	Er22	Invalid release number from the CD processor

Service shell

The service shell tests the video, the CD drive and servo, the input and output ports and the audio circuits. Start it by joining the RXD and TXD lines of port 1 (pins 2 and 3) during start-up: fit the test plug before switching on. Use only a CD-DA disc for the drive, servo and audio tests. The main menu offers CD PLAYER, DUART (CDI 601 and 602 only), APU/KEY, TEST IMAGE and EXIT.

• CD PLAYER: the X BUS test checks the link between the CDIC and the drive processor, and DIG OUT checks that the CDIC receives the digital output signal; both answer OK or NO RESPONSE. DRIVE TEST runs the standard CD player service loop: mode 0 shows the drive software release, mode 1 starts focus (IN FOCUS, or NO FOCUS after 16 attempts), mode 2 runs the turntable motor, mode 3 lets ARM IN and ARM OUT move the arm in small jumps, and NEXT STEP from mode 3 starts normal play, for which the test jumper must come out.
• APU/KEY: sets the attenuation of each audio path (47 is full attenuation, no sound) and switches mono and stereo, and shows the name of any remote control or front panel key that is pressed.
• TEST IMAGE: shows a colour bar pattern.

If the service shell will not start with the test plug, suspect the connections between port 1 and the slave processor, the test plug itself, or the slave processor. If the player shell will not start either, run the low-level test.

Drive error messages in the service shell (display A5 xx0000)

xx	Meaning	xx	Meaning
2	Focus error	30	Too many grooves to jump
3	Radial error	31	Search time-out
5	Off error (TL low for 50 ms)	32	Binary search error
6	Jump error	33	Search index error
7	Subcode error, no valid subcode in 3 s	34	Search time error
8	TOC error: out of lead-in area while reading the TOC	37	Selection error

Disc does not start

At start-up the drive processor pulls the arm inwards and starts the focus search, waits 400 ms, then starts the turntable motor and looks for four track-loss (TL) pulses within 400 ms. If they do not come it tries once more, and then stops with the motor and the laser off.

1. Check the supply, clock and reset of the drive processor (MC68HSC05C8).
2. If they are present, run the X BUS test in the service shell and look for activity on the X-bus and the SPI bus.
3. If the processors cannot talk to each other, run the low-level test to check the system control circuits.
4. If the buses work, use the service shell's drive test modes to check the pickup, the turntable and the swing arm, and then measure the servo circuits.

The CDI 220/00 service manual gives these measurements for its CD panel with Testdisc 5, track 1: 0.7 V DC ±10 % across 3114 (laser current, set at the factory) and +400 mV DC ±10 % across 2151 (focus).

No sound

1. With the servo working, look for activity on the I²S lines (DAAB, CLAB, WSAB) and the subcode lines (SCAB, SDAB) from the SAA7310 decoder.
2. If there is none, check the decoder's supply and its HF and XIN inputs. If there is activity, check the ADOC circuit.
3. If the drive and decoder are working, the fault is probably on the APU. Lift it on its extension cables. The I²S bus from the MMC can be checked on the 7-pin connector A16 on top of the APU, and the analogue output on connector A9 underneath.
4. If the inputs are present but not the analogue output, the fault is on the APU. If the APU output is present, follow the signal through the CD unit, including the KILL mute switches and the output buffers.

The KILL signal, derived from RESETCD, mutes the audio outputs during reset so that the electrolytic capacitors in the audio circuit discharge without a pop.

Picture faults

• Player shell shown but no video from the disc: the encoder panel and the video synthesiser are working, so the fault is in the video decoding section of the MMC panel.
• No video at all: check the S-Video, RF and CVBS outputs. If none has a signal, check the RGB, composite sync and supply inputs to the video encoder panel on connector 1061, underneath it. If they are present, the MMC panel is working; check the encoder IC and its two supplies. If both supplies are missing, check resistor 3660; if only Vcc1 is missing, check 3618; if only Vcc2 is missing, check 3619.
• No colour: check the subcarrier oscillator at pin 6 of the encoder IC 7601, then the chroma output at pin 15, the chroma input at pin 17 and the coupling parts between them, and the composite output at pin 20. A missing chroma output with a good oscillator points to IC7601.

Settings lost or "memory full"

The Timekeeper NVRAM on the MMC unit holds the settings. A flat cell loses them at every power-off, and can leave the player at a light blue screen or a "memory full" error. Replacement is covered on the Philips CDI 910 General Maintenance page.

Related pages

• Philips CDI 910
• Philips CDI 910 General Maintenance
• Philips CDI 910 Capacitor Replacement Guide
• Philips CDI 910 Documentation
• Philips CDI 605 Troubleshooting Guide
• Capacitor Failure Symptoms