Philips AS99 Service Manual
For internal use only PHILIPS
ISSUE AS99.01 (99-02-12)
Published by:
Service Department Audio Systems
LINEOFBUSINESSAUDIOSYSTEMS
SERVICENEWSLETTER
01.01TYPENUMBER(S):CDC751,CDC752
INFORMATION :During transportation the pin on the Crank (pos 96) might jump out of
the groove on the Tray (pos 108).
From production wk9835 onwards, the Tray and Crank have been
modified.The groove on the tray is now deeper and likewise the pin
on the Crank is 3mm longer.
Due to this change the new Crank does not fit into the old Tray
anymore.But it is still possible to use the old Crank on the new Tray.
The service code numbers for the Cranks are as follows:
4822 535 40105 Old Crank
4822 402 11241 New Crank
Service Newsletter 1999 – Audio Systems 1/10
The new Tray can be recognized by its 10mm deep groove.
Because of limited stock of old Cranks, new Cranks have to be
reworked for sets with an old Tray. This is done by cutting the pin by
3mm with a sharp NT-cutter (give it a clean cut & do not deform its
circular cross-section) as shown below.
REMARKS :
01.02 TYPENUMBER(S): CDC775
INFORMATION : Corrections to the Service Manual
On page 1-2, CDC775/01 a 2-position voltage selector is shown
instead of a 4-position type.
The 4 positions are: 110V/127V/220-230V/240V.
On page 8-4, capacitor 2863 and resistor 3885 are drawn as
provision. Both components will be assembled from production start
onwards to improve playability of “Thin Disc”.
2863 4822 126 13689 18pF 1% 63V
3885 4822 051 20153 15kΩ 5% 0,1W
REMARKS :
Service Newsletter 1999 – Audio Systems 2/10
01.03 TYPENUMBER(S): ALL CDR TYPENUMBERS
INFORMATION : The user problems in this publication are separated into the following
categories:
1. Playback behaviour
2. Recording behaviour
3. Operating behaviour
1. PLAYBACK
1.1. Display indicates: No disc
◆ Indeed no disc inserted
◆ Inserted disc is not recognised by Loader CDR mechanism
(defective disc or damaged disc)
◆ Does the set work properly with another CDDA disc (pre-recorded Audio disc)?
❏ If Yes then disc is indeed defective
❏ If No then check the functioning of the set.
◆ Disc is not positioned correctly on tray at inserting and therefore not recognised by
Loader CDR mechanism, reposition disc on tray.
1.2. CD-RW disc is not recognised
◆ Is it a CD-RW Digital Audio disc?
❏ If Yes and if the set is working properly on other recording discs, this par ticular disc
should be “DC-Erased” (Power off, ERASE + RECORD simultaneously and switch
Power on) This operation takes about 37 minutes and returns that CD-RW disc to its
virginal status again.
2. RECORDING
2.1. Analogue input signal recorded is distor ted at Playback.
◆ When recording analogue signals via tape or cassetterecording customer is used to
overpower the input signal.This brings more dynamic in recorded signal.
◆ For digital recording there is enough dynamic space between 0 dB till about -95 dB, so
overpowering is not necessary, the opposite is true; by digitalizing an overpowered
signal ‘mutes’ are converted, resulting in the distorted stored signal
2.2. Digital connected, tracks are not incremented
◆ Is Auto track increment function switched on. If not switch on Automatic track increment
◆ Digital source is using another digital output than IEC958 format (consumer part). This
is due to the transmitted subcode information which contains other data than the subcode information in the CD-format.To have the advantage of digital recording, the
Digital Audio Data is recorded without any problem. However the track-increment bit is
not transferred.
Service Newsletter 1999 – Audio Systems 3/10
2.3. Disc full after some or a few tracks.
Disc full message can be the result after a misrecording.
◆ Misrecordings due to customer actions are:
• bumps against recorder: prevent bumps onto the set during recording process.
• dust on disc: prevent dust particles on disc
• scratches on disc: prevent scratches on disc
• set is suddenly powered off: prevent switching off!!
◆ Misrecording due to improper working of CD Recording Module:
• In case the error occurs always at the same time indication then Optical Pick-up Unit
is not exactly following the Pregroove track on that position: replace CD-Recording
Module (CDR765, CDR760, CDR560, CDR538; 4822 691 10737) or the CDRLoader
module part CDR870, CDR880: 4822 218 12745)
◆ In case a CD-R disc is used, each misrecording will automatically activate the finalizing
process of the recorder, because after a misrecording it is not possible to add further
recordings onto that CD-R disc.To have all proper recordings stored, the TOC of the
disc is filled.
◆ In case a CD-RW disc is used, the last recorded track will be overwritten when making
further new recordings. Here the disc is not finalized automatically, but PMA (program
memory area) is filled with the number of proper recorded tracks.
2.4. Analog input is so low that tracknumber is incremented and recording stops.
◆ If analog input signal starts very low (-35 dB) and automatic track increment is switched
on then track nummer x will be followed by next number (x+1) after 4 seconds. If this
low signal still continues the recording will be switched off after some seconds.
◆ By applying Manually track increment this signal can be recorded.
◆ Automatic switch off has been modified by adapting µP software program in CDR765,
CDR760, CDR560, CDR538.
2.5. Loud noise on CD-RW disc
◆ CD-RW erasings are only done in PMA.The or iginal signal will be overwritten later on. It
might occur that the overwriting does not start at exactly the beginning of the frame of
the track to be overwritten. In case overwritten signal consisted out of loud signal, then
this short remaining signal can give this suddenly loud noise.
◆ For this phenomenon no better solution is possible.
3. OPERATING
3.1. Finalizing takes approx. 5 minutes
◆ Normally finalizing takes approx. 2 minutes.
◆ Due to the fact that finalizing is done at speed N=2.
◆ In case something goes wrong finalizing is automatically switched over to speed N=1
and procedure will restart. (4 minutes)
◆ Now in IFU is stated:“ Finalizing takes at least 2 minutes”
3.2. CD-sync activated and in first track 1 second deviation upon original disc.
◆ Via CD-sync, the recorder is brought in record standby position at the last recorded
position on the program area.
◆ When CD-player is started the digital signal is brought to digital in.When this signal
arrives immediately the linking procedure starts. After reading the last recorded 14
frames the recording of the digital input signal starts. As no buffer is used the first
frames are not stored. (Max. about 400 msec. are lost)
Service Newsletter 1999 – Audio Systems 4/10
3.3. How to erase one track between other tracks on CD-RW disc?
◆ It is not possible to erase tracks between other tracks.Only the last recorded track can
be erased. In case of an erasure between tracks make first a copy of the to be safed
tracks to another disc and then erase track after track to the desired position and add
stored recording again.
3.4. Can a copy of another copy be made?
◆ For Philips Digital Audio CDR recorders SCMS protocol is valid
◆ This applies even to devices without a digital output
◆ SCMS allows any number of digital copies of original sound carriers, but prevents
further digital copies of this created master.
◆ copies of this created master can only be made via D/A -> A/D conversion.
◆ According to audio interface standard IEC958, via channel status bit (timeslot30), the
channel status word consists out of 384 bits per blok,each bit repeated twice so 192
channel status bits per blok are available. In channel status word every digital source is
identified by an 8-bit “category code” Category code is formed by bit 8-15 of the channel
status word.
◆ bit 15 of timeslot 30 or the last bit of the category code is called L-bit. This bit
indicates an original source, commercially released pre-recorded software (L=“1”) or a
personal recording or “home copy” (L=“0”) No indication.
◆ Control code gives the transmission mode and the copy protection status of the signal
that is transmitted.
◆ the transmission mode is given by the bits 0 and 1 of the channel status word.
◆ Bit 2 contains the copy status (C-bit).
◆ C-bit = “0” for protected and “1”for unprotected material ”alt” for “home copy of copyright
protected original”
◆ On recorded disc the copy bit defines the copy status:
◆ Q-control bit 1 (copy bit) copy protection status:
◆ Q-control bit 1 = “1” for protected,
◆ Q-control bit 1 = “0” for unprotected material
◆ Q-control bit 1 = alternating between “0” and “1” (alt) for “home copy of copyright
protected original”
On recorded disc the copy bit defines the copy status summarised in one table:
3.5. Can CD-i disc be copied to Audio CDRrecorder?
◆ Digitally connected only the CD DA tracks on that disc
◆ CD-i disc complete is not possible, only CD DA discs.
◆ Only via analogue connection the Audio signal can be copied
3.6. Can VCD disc be copied to Audio CDRrecorder?
◆ Digitally connected only the CD DA tracks on that disc
◆ VCD disc complete is not possible, only CD DA discs
◆ Only via analogue connection the Audio signal can be copied
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Service Newsletter 1999 – Audio Systems 5/10
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