Notes on the Troubleshooting and Repair of Compact Disc Players and CDROM Drives


  13.3) Testing of motors

If your player uses a brushless DC motor for the spindle then you may not be
able to perform any electrical tests as the commutation control may be
external on the circuit board somewhere.  These do not fail very often, either.

An open or shorted winding may result in a 'bad spot' - a position at which
the motor may get stuck.  Rotate the motor by hand a quarter turn and
try it again.  If it runs now either for a fraction of a turn or behaves
normally, then replacement will probably be needed since it will get stuck
at the same point at some point in the future.  Check it with an ohmmeter.

Also check between each terminal and the case - the reading should be high,
greater than 1M ohm.  A low reading indicates a short.  The motor may still
work when removed from the equipment but depending on what the case is
connected to, may result in overheating, loss of power, or damage to the
driving circuits when mounted (and connected) to the chassis.

Clip the ohmmeter leads to the motor terminals and rotate the shaft extremely
slowly.  The motor will act as a generator as your spin it resulting in the
resistance readings increasing or decreasing depending on direction.  However,
the readings should stabilize once you stop.

The resistance should be fairly constant as the shaft is rotated with periodic
dips where pairs of commutator segments are shorted by the brushes.  The
number of cycles per revolution is determined by the number of commutator
segments used (most use only 3).  Any extremely low reading may indicate a
shorted winding.  An unusually high reading may indicate an open winding or
dirty commutator.

Cleaning may help a motor with an open or short or dead spot as noted below.

Typical resistance of these motors will be 10 to 25 ohms (though I have seen
some apparently good motors reading as low as 5 ohms), fairly constant as one
rotates the shaft except for dips at 3 points where the brushes short out each
pair of commutator segments (there are generally 3 segments on these motors).

A motor can be tested for basic functionality by disconnecting it from the
circuit board and powering it from a couple of 1.5 volt alkaline cells in
series (3 V) or other power supply up to 9 V or so.

WARNING: Never attempt to power a motor with an external battery or power
supply when the motor is attached to the circuit board - you may blow
electronic components on the circuit board and complicate your problems.
Disconnect *both* terminals and label the wires or motor orientation so
you can reconnect it with the proper polarity.

If you use a variable power supply, the motor will start spinning slowing at
less than a volt and continue without tending to stop at some point in its
rotation.  Using your fingers to monitor the torque produced as it rotates
can also provide an indication of its health.  It should be fairly uniform
with slight periodic dips due to the commutator construction and number of

It is also possible to confirm that the electronics are attempting to drive
the motor by substituting a 15 or 20 ohm 1 W resistor for the motor.  The
driver circuit should develop a few volts across this load when it is supposed
to be active.  If there is no voltage at any time, then the driver may be
blown or not have power, or the logic is not instructing the motor to spin!

  13.4) Reviving a partially shorted or erratic PM motor

Dirt or grime on the commutator can result in intermittent contact and erratic
operation.  Carbon or metal particle buildup can partially short the motor
making it impossible for the controller to provide enough voltage to maintain
desired speed.  Sometimes, a quick squirt of degreaser through the ventilation
holes at the connection end will blow out the shorting material.  Too much will
ruin the motor, but it would need replacement otherwise anyway.  This has
worked on Pioneer PDM series spindle motors.  I have heard of people using
carburetor cleaner successfully but I would recommend something a little less
harsh to start.  Contact, circuit board, or tape head cleaner may work.

Another technique is to disconnect the motor completely from the electronics
and power it for a few seconds in each direction from a 9 V or so DC source.
This may blow out the crud.  The long term reliability of both of these
approaches is unknown.

WARNING: Never attempt to power a motor with an external battery or power
supply when the motor is attached to the circuit board - you may blow
electronic components on the circuit board and complicate your problems.
Disconnect *both* terminals and label the wires or motor orientation so
you can reconnect it with the proper polarity.

It is sometimes possible to disassemble the motor and clean it more
thoroughly but this is a painstaking task best avoided if possible.

If you do manage to revive it, also see the section: "Spindle motor drive modification to minimize chances of future problems".

  13.5) Replacement motors

The spindle motor should be replaced with an identical unit though it doesn't
have to be the exact manufacturer's part number - universal substitutes are
often available at a much lower price.

However, there may be alternatives for other types.  Most of the other small
PM motors found in CD players and CDROM drives (as well as VCRs and other
consumer electronics and small appliances) are basically pretty similar.  The
important differences are mainly mechanical - size, mounting, shaft length,
etc.  There may be variations in nominal voltage and current usage but for
non-critical applications like drawer loading or disc changing, if you can
make a generic replacement fit the space and attach to the drive components,
There is a good chance that it will work well enough.  Such replacements may
be available from companies like those listed in the section: "Recommended parts suppliers".  Check a few catalogs!

  13.6) Motor bearing problems

A dry or worn bearing can make the motor too difficult to turn properly or
introduce unacceptable wobble (runout) into the shaft as it rotates.

Feel and listen for a dry bearing:

The shaft may be difficult to turn or it may turn with uneven torque.
A motor with a worn or dry bearing may make a spine tingling high pitched
sound when it is turning under power.  A drop of light machine oil (e.g.
electric motor oil) may cure a dry noisy bearing - at least temporarily.

For spindle motors (these are the only motors in CD players where runout
is critical), try wiggling the shaft from side-to-side - any detectable
movement is an indication of runout.  At some point, this will be bad enough
such that the focus and tracking servos will be unable to compensate for the
runout and audio noise and skipping may result.  Some oil may help but a
spindle motor with a worn bearing will require replacement eventually.
Furthermore, it may prove impossible to reach the bearing(s) to lubricate
them properly.

See the section: "Spindle motor problems" for more information.

  13.7) Spindle motor problems

The following are some indications that the spindle motor may be defective
or need attention.  However, insufficient spindle motor voltage or current
could also be due to spindle motor driver faults, incorrect power supply
voltages, or logic problems.

Note: If the disc doesn't spin at all, try rotating it by hand while it is
trying (or with the servos enabled if it has a TEST mode).  If you hear that
'gritty' sound, the focus and probably tracking servos are working but the
spindle motor or driver are faulty.

* Focus is successful but disc does not spin (dead motor or dead spot on
  motor, shorted motor, bad connection).

* Disc spins but at too slow a rate or is erratic or needs some help (weak
  motor or dead spot).  Reading of disc directory may be erratic.  (Try
  helping motor out by hand).

* Voltage across spindle motor is only 1 V or less while attempting to spinup
  and read the directory and climbs to 5 V or more with the motor disconnected
  (partially shorted motor).

* Spindle bearing runout is excessive (i.e., detectable by wiggling the
  spindle from side to side) or spindle motor bearing is dry or tight (try
  lubricating if possible).

* Repetitive noise or dropouts at the disc rotation frequency or twice the
  disc rotation frequency.  This may get worse toward the end or outer tracks
  of the disc.  (Excessive spindle bearing runout or bad windings).

Check the motor before replacement (see the section: "Small motors in CD players" for general motor problems and testing).  You should be able to
easily confirm or eliminate the spindle motor as the cause of your problems.
If either of the cleaning or rejuvenation techniques make a significant
difference in performance, then the motor is almost certainly at fault.  If
the player now functions normally - leave it alone or, perhaps, try the
circuit modifications suggested in the section: "Spindle motor drive modification to minimize chances of future problems".

The spindle motor is often blamed for everything from long distance skipping
(coarse tracking problem) to disc spinning too fast or in wrong direction (a
control problem).  Spindle motors do fail but they are not at the root of all

  13.8) Spindle motor drive modification to minimize chances of future problems

This suggestion is directed toward Pioneer players of the PD and PDM
series with known common spindle motor problems.  It may apply to other
Pioneer models and other brands as well.  It can be used whether you
have just rejuventated an existing motor or installed a replacement.

For Pioneer players, there is actually a circuit modification to reduce the
possibility of repeat problems but it requires changes to the wiring - cuts
and jumpers - which I prefer to avoid.

My recommendation is to try the following which can usually be added at
the motor terminals.  (I have not done this yet, so no guarantees):

Put a series string of 4 1N400X diodes in parallel with another similar string
in the opposite direction across the motor terminals.  This will limit the
maximum voltage to about 3 V instead of the 6 V or more that it is now.  The
reduced voltage should reduce chance of damage to the commutator at spin-up.
On the Pioneers at least, the motor driver should not mind the extra load
during any peaks where the diodes kick in.

It may take a couple seconds extra to start up but I believe it will still
work fine otherwise.

If you do this, let me know how it works.

  13.9) Spindle motor replacement

Mark the height of the old spindle platter before you attempt to remove
it.  The best approach is to make a shim that will fit between the bottom
of the spindle platter and the motor as a stop.  The height is usually
specified to a precision of 1/10 of a mm.  Too low or too high and the
disc may rub.  This is probably overhill - 1/2 mm is probably good enough
but try to get it as close as possible.  The focus servo offset adjustment
will make up for any height error in so far as focus is concerned.

The spindle is often press fit and difficult to remove without damage.
It is critical that when the spindle is replaced, it be mounted perfectly
with no wobble.  If you can obtain a new spindle platter with the new
motor, this is the best option.  If not, take every precaution to prevent
damage to the spindle platter during removal - even it it means destroying
the old motor in the process.  See the section: "Spindle platform pulling".

When press fitting the new spindle, the use of an arbor press or drill
press is highly recommended.  Put a block of wood under the bottom of
the motor and your previously made shim between the spindle platter and
the motor.  Press straight down - slowly and firmly.  Err on the side of
being to high and check the height.  Repeat until you get it perfect.  It
is much easier to press a little more than to raise the height if you
should go to far.

If there is a set screw, your job is much easier.  Other mounting schemes
may be employed - use your judgement in replacement procedure.  For
non-press fit installations, a drop of loctite or nail polish will reduce
the chance of it working loose.

  13.10) Unknown spindle platter height when replacing spindle motor

What was your excuse for not marking it?  Oh, an elephant sat on the player
and that is why the motor needed replacing but the height was already messed
up :-).

If the player operates normally after spindle motor replacement, as they say
"If it works, use it".  I wouldn't worry about it.  The focus servo has a wide
range.  If you are curious, try to locate the test point for focus error.  It
should probably be a noisy waveform centered around zero volts.  However, this
may not be the case and you would need the service manual to be sure of what
it should be.  As long as the player seems to locate the disc directory quickly
and plays normally, leave it alone!

However, if it now has problems either taking a long time to start play or
exhibiting unusual noise or skipping during play, you should probably try to
obtain the spindle platter height specification and set it more accurately.

I definitely would not recommend mucking with the spindle platter height
unnecessarily if it is a press-fit.  You would probably end up with a bent
shaft and need for yet another replacement motor.  However, if the spindle
platform is secured with a set screw, you can try to adjust it to minimize
focus error and/or optimize playback performance.

  13.11) Spindle platform pulling

I was able to remove the spindle platform on a Philips CD pickup using the
lawn mower engine flywheel pulling approach - levers under both sides of the
platform so the pressure is upwards and not sideways while tapping on the
center of the shaft with a thin punch.  Thus, there was no shaft bending.
I believe that the motor survived without damage.

I was actually going to 'machine' a mini-flywheel puller but then I
said: "What the heck, that is too much work :-)"

In any case, the spindle platform is completely undamaged and the motor
could probably be reused.

However, be careful what you are prying against - the mounting may use tiny
screws into plastic or something equally fragile.

Of course, if you plan on doing any serious hammering, remove all the
delicate optical and electronic components first!

  13.12) Correcting spindle platform wobble

This assumes the bearings are in good condition but the shaft has somehow
gotten slightly bent.  You might ask: How could this happen?  Once cause could
be using an improper technique to remove or attempt to remove or install the
spindle platform from/to the motor shaft or something heavy falling on the
player.  Right, I know; in this case, a bent shaft will likely be the least
of your problems! :-)

(From: Filip M. Gieszczykiewicz (filipg@repairfaq.org)).

I use something as simple as a pencil. Start the motor going and put the pencil
right above - but not touching - the part that is bent.  Now move it in tiny
increments towards the bent part. When you hear the first tiny "scrape", stop
the motor and note where the pencil mark appears. This is the place you want to
press down to even it out.

This is loads of fun with a CD spindle motor and sometimes it's just easier
to get a replacement. Trust me.

  13.13) Sled motor problems

The following applies to sled positioners using conventional permanent magnet
motors with the typical gear or screw mechanism.  (Those using linear motors
use closed loop servo systems with a drive coil and sense coil.  About all
you can do to test these without a schematic is to check for continuity of
the two coils.)

Sled motors tend to be less likely to fail than spindle motors but can
suffer from similar afflictions.

The following are some indications that the spindle motor may be defective
or need attention.  However, insufficient sled motor voltage or current
could also be due to sled motor driver faults, incorrect power supply
voltages, or logic problems.  These problems could also be of an erratic
nature if the motor has a dead spot or is partially shorted.

The sled motor (or its driver and associated circuitry) may be at fault if:

* The sled fails to reset to the inner track.

* Focus is established and the disc begins spinning at the proper speed for
  the current pickup location but the pickup fails to move to the selected
  track location.

* There are problems with discs repeating more-or-less the same musical
  segment every few seconds (the sled gets stuck) or long distance skipping
  (the sled sticks but then once enough of a fine tracking error develops,
  breaks free and overshoots the proper location).

The motor may have a dead or weak spot in its rotation.  Rotate it by hand
1/4 turn or so and see if it now spinds normally or a fraction of a turn.
See the section: "Testing of motors".

Of course, any of these could also be due to mechanical problems as well
so eliminate these as possibilities first.

  13.14) Sled motor drivers

The sled motor may actually receive its drive from two sources (maybe more)
as shown conceptually in the diagram below.  These may or may not be separate
physical outputs tied together:

                                 Slew+ o--------+
                        |\                      |
           Tref+ o------|+ \                    |
                        |    >------------+     |
                     +--|- /              |     |    |\  Sled Drive
                     |  |/ TE+ Comp       |     +----|+ \  
                     |                    +----------|+   \ 
  Tracking Error o---+                               |      >--------o + Sled
                     |                    +----------|-   /      +---o - Motor
                     |  |\ TE- Comp       |     +----|- /       _|_
                     +--|+ \              |     |    |/          -
                        |    >------------+     |
           TRef- o------|- /                    |
                        |/                      |
                                 Slew- o--------+

1. Slew driver - this is used when the pickup is resetting or moving across
   the disc.  The motor is commanded to move smoothly in either direction
   or is searching for the general vicinity of the starting location (time

   Where the pickup is unable to reset to the inner track or unable to move
   to an outer track during seek operations, a part of this driver or its
   associated circuitry may be at fault.

3. Coarse tracking driver - this is used to move the sled a small amount
   during play to recenter the pickup once the fine tracking error exceeds
   a threshold.  Many designs will do away with explicit comparators (as
   shown above) and just use the friction of the sled motor/mechanics to
   result in movement once the voltage on the motor becomes large enough.
   This would seem to waste power, however, and be undesirable for battery
   operated portables, at least.

   Where the seek operation completes normally and the music starts playing
   but then gets stuck or jumps back and repeats after a few seconds, the
   coarse tracking driver or its associated circuitry may be at fault.

Any of these symptoms may also be caused by a defective sled motor or
mechanical problems - probably more likely than bad electronics.

Chapter 14) Notes on Specific Equipment

  14.1) Pioneer PD/M series players/changers do not recognize discs

(Refer to the photo of the Pioneer CD Player Optical Deck for parts

Where a Pioneer player or changer does not recognize discs, the most common
causes are:

1. Partially shorted spindle motor due to 'crud' on commutator.  Cleaning
   may be possible.  Generally, disc will spin but at insufficient speed.
   Try TEST MODE toward latter (outer) part of disc as the required rotation
   rate is lower and/or check voltage to motor, below.  See the section:
   "Reviving a partially shorted or erratic PM motor".

2. Cracks in flex cable to optical pickup assembly - replacement of flex cable
   will be required.  This may also result in erratic operation while playing.
   The Pioneer replacement part number for the improved version of one common
   cable is PNP-1343 but confirm this is correct for your model before you
   order.  Sometimes, the flex cable is just not positioned properly (clear
   of the metal cover) and just needs to be 'adjusted'.

3. Collapsed rubber suspension grommets.  There may be a scraping or clicking
   sound associated with this failure.  For changers, gently lift up on the
   optical pickup assembly while the disc is attempting to spin to see if the
   disc is recognized and will play.  Replace the deteriorated grommets.

For general information, see the sections starting with: "Startup sequence".

  14.2) Pioneer PD/M series test mode

The TEST mode available on some CD players is extremely useful for narrowing
down problems.  The following are for the Pioneer PD/M series of CD players
and changers:

* To enter TEST mode, press the TEST button while turning POWER ON and then
  hold it on for at least 1 second.

  - Some models only have a set of contacts - Pioneer saved 2 cents on a
    switch!  Short between these with a piece of wire or a paper clip instead
    of pushing the button.

  - On players with a standby mode (not a hard on/off switch), plug the unit
    in while pressing the TEST button or shorting the contacts.

  The TEST button or contacts are located on the main board (usually near the
  front right corner - may be obscured by cables).

Once TEST mode is engaged, the servos can be controlled from the front panel:

* STOP turns all servos OFF.
* TRACK FWD (>>|) enables FOCUS servo (and loads disc 1 in changer).
* PLAY enables SPINDLE servo.
* PAUSE enables TRACKING servo.
* MANUAL SEARCH FWD (>>) or REV (<<) to move the optical pickup.

Depending on model, the specific functions and behavior of the front panel
buttons in TEST mode may vary slightly.

WARNING: Normal safety checks are disabled in TEST mode.  Thus, the laser may
remain on as long as focus/tracking/spindle servos are engaged even if no disc
is in place.  Take care.

Power cycle (by unplugging if necessary) to return to normal mode.

  14.3) Pioneer spindle motor voltage (operating normally)

Here are the typical measurements for the PD/M series players:

* Spinup:                         >2.5 v.
* Time to lock (est):              1-2 sec.

* Start of disc (500 rpm):          1.0 v.
* End of disc (200 rpm):             .5 v.

  14.4) Pioneer spindle motor problems

When bad, spindle servo drive tops out at .6 V and 100 ma.  Player is unable
to spin up to required 500 rpm to read disc directory.

While exact cause is unclear, theory is that large voltage applied at startup
followed by long periods of very low voltage (.5-2 V) operation allows
conductive crud (carbon) to build up on commutator eventually reducing
resistance to the point where the driver cannot apply enough voltage to
achieve 500 rpm.

A short squirt of degreaser through motor access hole had an immediate
dramatic effect returning operation to normal.  It is not known how long this
will last.  (Also see the alternative procedure in section: "Reviving a partially shorted or erratic PM motor".)

Collateral symptom: Spindle motor servo drive IC becomes quite warm when
attempting to power shorted motor.  However, it does not appear to be harmed.

Use TEST mode to play disc at outer track.  If this is normal, then spindle
motor is probably bad as the rotation speed at the outer tracks is less (200
rpm) and a partially shorted motor may still run fast enough for this.

  14.5) Pioneer PD/M series servo adjustment procedure

The following procedure assumes that unit is functional but internal
controls may have been moved from their correct position.  This procedure
has been determined experimentally and is subject to change without notice.
If you have not touched the internal controls, there is no need to perform
this procedure.  Use techniques and observations discussed elsewhere in this

A number of Pioneer CD players have used very similar designs.  However,
technology sometimes the implementation changes dramatically between units
with virtually identical model numbers.  It is known that this adjustment
procedure applies to many older Pioneer single disc players (e.g., PD5100)
and magazine changers (e.g., PDM400/500/600 etc,).  However, newer models
that appear virtually identical to these may require a totally different
adjustment procedure.  Therefore, use at your own risk!  With minor (and
obvious) modifications, this general approach should also apply to many CD
players from various other manufacturers as well.

I also recommend you read the section: "General servo adjustment procedure"
in its entirety before proceeding to tweak your Pioneer player.


* Controls on the main board have been moved or are in an unknown state but 
  not on the flex-cable or optical pickup assembly.

* The player is otherwise functional - no physical damage.

And now for the fun:

1.  Set all the main board controls to their midpoint.

2.  Power up the unit in TEST MODE (hold down the TEST button while
    powering on.

3.  Adjust TR.BAL (Tracking Balance) to the center of the range over which
    the sled remains stationary.  Outside this range, the pickup will slew
    to one end or the other.

4.  While monitoring TP1-6 (FO.ER, Focus Error) with a VOM or DVM, adjust
    FO.OFS (Focus Offset) for a reading of 0V +/- 10 MV.  Note: I have
    found that on some players, this may not actually be quite optimal
    and fine adjustment be beneficial.

5.  While monitoring TP1-2 (TR.ER, Focus Error) with a VOM or DVM, adjust
    TR.OFS (Tracking Offset) for a reading of 0V +/- 10 MV.  Note: I have
    found that on some players, this may not actually be quite optimal
    and fine adjustment be beneficial.

6.  Load a magazine with a disc in slot 1 and press >>|, TRACK SEARCH Forward.
    This should load the disc and enable focus servo.

7.  Use MANUAL SEARCH REV (<<) to position sled at beginning of disc.

8.  Press PLAY.  This enables the spindle servo.  Disc should now spin up
    and lock at at around 500 rpm.  If disc does not start or appears not
    to reach correct speed, check voltage on spindle motor.  It should be
    greater than 2.5 volts during spinup.  The most common cause of low
    voltage is a dirty partially shorted commutator/brush assembly inside
    the motor; clean or replace as necessary.  WARNING: if the disc spindle
    speed runs away, turn power off and wait for spindle to stop completely.
    VCO control may be set to high; turn counterclockwise 1/4 turn and start
    from the beginning.

9.  Press PAUSE.  This locks the tracking servo.  The display should show the
    disc TRACK and TIME.  Alternately pressing >> or << should move pickup,
    then press PAUSE to start play again.  Audio will be correct at output.
    Correct display and sound only near end of disc indicates a spindle
    motor unable to achieve sufficient speed (see above).

10. Adjust the VCO control to the midpoint of range in which disc plays

11. Set RF.OFS to the midpoint of the range over which play continues normally.

12. Set FO.GAIN to midpoint of range over which it locks.  CAUTION: the disc
    may enter a runaway state if you go to far.  Check at both the beginning
    and end of the disc.  FO.GAIN may need to be increased if the player is
    overly sensitive to bumps or disc wobble.  It may need to be decreased if
    sensitivity to disc defects is too high.

13. Set TR.GAIN to the midpoint of range over which it locks.  CAUTION: the
    disc may enter a runaway state if you go to far.  Check at both the
    beginning and end of the disc.  TR.GAIN may need to be increased if the
    player is overly sensitive to bumps or disc wobble; it may need to be
    decreased if sensitivity to disc defects is too high.

14. Press STOP.  The disc should unload.  Exit TEST MODE by turning power
    off and on again.  Confirm that the disc loads properly and that the
    directory comes up quickly and the music starts without excessive delay,
    hunting, or hesitation.

15. Test forward and reverse search and seek functions for proper behavior.
    Some slight adjustments to tracking balance or fine tracking offset may
    be needed to equalize the forward and reverse search or seek speed.

16. The player should now operate normally.  However some tweaking of the gain
    controls may be necessary (as described above) for optimum defective disc
    and track seek performance over entire disc.

If you have an oscilloscope capable of at least 5 MHz bandwidth, you can now
optimize the amplitude and stability of the 'eye' pattern at the RF testpoint
by going back and touching up the various offset (RF, focus, fine tracking)
adjustments.  Unless otherwise instructed by the service manual, it is probably
safe to assume that the RF signal should be maximum when everything is properly
adjusted.  For example, if TR.OFS is not set properly, you may find that the
RF signal amplitude *decreases* when the tracking servo is closed since the
laser beam is now consistently off-center with respect to the row of pits and
lands.  (With the servo loop open, the beam was crossing tracks more or less
at random so it was sometimes centered!)  For the Pioneers I have seen, it
appears that the FO.OFS and TR.OFS may *not* be set optimally by the static
adjustments (4) and (5), above.

  14.6) Pioneer PD-7010 adjustment procedure (from Davidson)

Note: See Pioneer TEST mode description in the section: "Pioneer PD/M series test mode".

1. Laser Power - Normal mode.  Press PLAY - Laser power should be set to:

        .26 mW +/- .02 mW.  Adjust VR1 to spec.

2. PLL VCO Free Run Frequency:

   * Set the player to TEST mode.

   * Press STOP to switch all servos off.

   * Press TRACK FWD to enable the FOCUS servo.

   * Press PLAY to enable the SPINDLE servo.

   * Observe the waveform at pin 8 of IC8 (2/2) using a scope set to .5 V/div.
     This waveform can be found easily at the legs of C47.

     Note the center value of this waveform.

   * Using a core driver, adjust VL1 (VCO coil) so that the center value of
     this waveform is the same when PAUSE is pressed to switch on the TRACK

3. Tangential Adjustment:

   * Enter TEST mode and load the TEST disc??

   * Use the MANUAL SEARCH FWD key to put the pickup at the end of the disc.

   * Press TRACK FWD, PLAY, and PAUSE in that order to enable all servos.

   * Use the Scope to observe TP2, Pin 4 (RF Output).  Adjust the Tangential
     Adjustment Screw to obtain the clearest eye pattern.  This is the
     midpoint between the places where the pattern begins to deteriorate.

4. Tracking Offset and Focus Offset:

   * Enter TEST mode.

   * Adjust the voltage at TP1, Pin 9 TR (Tracking Return) to 0V +/- 10 mV
     by turning VR2 (Tracking Offset).

   * Adjust the voltage at TP1, Pin 3 FO.ER (Focus Error) to 0V +/- 10 mV by
     turning VR6 (FO.OF, Focus Offset).

5. Focus Gain:

   * Enter TEST mode.

   * Press STOP to disable all servos.

   * Adjust the frequency and output voltage of CH1 of the F.T.G. to 878 Hz
     and .2 V P-P.  What if I do not have an F.T.G.?

   * Connect the F.T.G. adjuster. Right :-).

   * Press TRACK FWD, PLAY, and PAUSE in that order.

   * Adjust VR3 FO.GA so that the green LED just comes on.  Right.

  14.7) Yamaha CD3 adjustment procedure (from Davidson)

1. Laser Power:

   * Remove the flapper.

   * Player should be in focus search mode.

   * Short terminals FD1 and R together.

   * Laser power should be .24-.30 mW.

   (Apply -9V +/- .5 V if the pickup is off the circuit board.)

2. HF Level:

   * Monitor HS with scope.  Peak to peak level should be between 1.5 and 2.5 V.

3. Focus Offset:

   * Set the TEST disc to PLAY.  Make the adjustment at the center of disc
     rotation (35 DHS).

   * Connect the oscilloscope to HS.  Adjust VR101 for the best eye pattern.

4. Tracking Gain:

   * PLAY mode.

   * ACVM to terminal Q and VE.

   * Apply 800 Hz, 100 mV rms to TD1 and GND with a 220K resistor in series
     from the audio oscillator.

   * Adjust VR104 so that ETE = (EQ + 5 dB) +/- 1 dB.

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Written by Samuel M. Goldwasser. | [mailto]. The most recent version is available on the WWW server http://www.repairfaq.org/ [Copyright] [Disclaimer]