Welcome to the Unofficial Kenwood L-07D Direct Drive Turntable Website Literature Page

Literature pertinent to the L-07D includes the instruction manuals, the service manuals, the sales brochure, the DS-20 Outer Disc Stabilizer Guide Book and the TS-10 Turntable Sheet Guide Book. All of the above referenced literature booklets are available on this page for viewing and printing. I have set the page size, such that each page should print out on a single sheet of paper on a standard printer.

I have also created some documents which I have developed from the L-07D & L-07D II schematics and service manuals. These documents help me troubleshoot and repair these decks. On this page, the above referenced documents are available for display below.

The pages below are from the French/German/Netherlands/Swedish L-07D instruction manual:

The pages below are from the English/French/Spanish L-07D II instruction manual:

My opinion is that Baerwald alignment (of 16.8mm overhang) sounds better than Löfgren alignment. Baerwald alignment geometrically allows better tracking on the inner grooves. The non-damped ultra-rigid design of the L-07D tonearm mechanism works better at the inner grooves when Baerwald alignment is used.

A Microsoft Excel spreadsheet showing calculation of Baerwald and Löfgren cartridge alignment calculations is posted at:

Kenwood L-07D Baerwald-Löfgren Cartridge Alignment Spreadsheet You can use the tabs at the bottom left of the spreadsheet to toggle between Baerwald and Löfgren spreadsheets.

Author's Recommended Method of Phonographic Cartridge Alignment on the L-07D

To level the platter, use an accurate circular bubble level on the subplatter. The platter sheet has a slight crown and should not be used for leveling. The bubble level in the plinth is not usually perfectly parallel to the platter.

For geometry to be correct, overhang and zenith must be perfect at proper VTA. I have used a several alignment tools including a metal Denessen Soundtractor and a Turntable Basics Phono Cartridge Alignment Tool. I have also measured actual overhang beyond the spindle along the overhang line.

Now I only use a custom made for the L-07D Wally Tractor. The Wally Tractor is far superior to any other method and/or device that I have tried in terms of accuracy as it is custom made exactly to the L-07D's tonearm geometry. I have reached the opinion that setting cartridge alignment with any universal cartridge alignment tool will result in imperfect cartridge alignment. For instructions on phono cartridge alignment, the reader is referred to Wally's Complete Turntable Setup Procedure which can be found on Wally Malewicz' web site: Wally's Vinyl Corner. If you order a Wally Tractor, be sure to let Wally know that the spindle diameter is 0.2825 inches.

I use Wally's recommendation to set SRA at 92 degrees. First set VTA so that the headshell is parallel to the record surface at correct VTF and at correct overhang and zenith per alignment protractor. Theoretically SRA should now be at 90 degrees. Now raise the tonearm at the base by 8.59mm to increase SRA 2 degreess to 92 degrees. (1mm increase in SRA = 4.29mm increase in rear arm pivot height). Next, reset overhang and zenith with alignment protractor and reset VTF. I then set azimuth with a non magnetic level on the headshell with the stylus raised off of the LP. You can loosen the headshell collar and then slight play of the headshell allows azimuth adjustment. The slight play is gone after finger tightening the headshell collar.

For setting VTF, forget about balance beam scales. They are not very inaccurate. Use a good digital stylus pressure gauge. Measurement should be taken at record surface level. All alignment parameters will affect VTF, so readjust VTF after completing platter leveling and phono cartridge alignment.

When zenith is properly set, the cartridge will be rotated slightly clockwise from the long axis of the headshell (when the headshell and cartridge are viewed from above). Achieving the necessary degree of cartridge rotation to set zenith correctly is generally not a problem with the L-07D headshell if the cartridge uses full length screws and nuts for attachment. However if the cartridge has fixed threaded screw holes, the captured design of the L-07D headshell finger might not allow sufficient cartridge rotation to set zenith correctly. Therefore, with cartridges that have fixed threaded screw holes and if correct zenith can not be achieved with the original headshell, I recommend the Sumiko HS-12 headshell, which is highly adjustable. I also recommend the Sumiko HS-12 headshell as an excellent alternative to the original L-07D headshell. If you have a Sumiko Flux Buster cartridge demagnitizer, it is very handy to use to position the headshell for final tightening of cartridge attachment hardware, off the tonearm and away from the turntable.

If you are using a DS-20 Outer Disk Stabilizer, pay careful attention to the tonearm cueing mechanism. It is important to prevent the stylus tip from contacting the Outer Disk Stabilizer, particularly when the platter is spinning, to prevent damage to the stylus and/or cartridge cantilever. With VTA optimally adjusted, be sure that the when the tonearm cueing mechanism is raised that the stylus tip is at least a couple of millimeters above the outer portion of the DS-20 (when DS-20 is on a record). If there is not enough clearance (and if there is room to raise the tonearm cueing mechanism cylinder further), adjust the tonearm cueing mechanism height by loosening the Allen grub screw(s) securing the cueing mechanism cylinder to tonearm collar with a 1.5mm metric Allen key. Prior to performing this procedure, the headshell should be removed and the tonearm should be removed from the tonearm base and taken over to a clean work area for this procedure. Do not put any force on the lifter support as you change the cylinder position or you may damage the cueing mechanism internally. Raising the cueing mechanism cylinder in relation to the tonearm collar will provide additional clearance between the stylus and the DS-20 Outer Disk Stabilizer. Re-tighten the Allen grub screw(s) after completing the adjustment. Please note that this procedure can only be done if there was some clearance between the screw securing the lifter support to the cueing piston and the rubber button above it when the tonearm is parked. Do not attempt this procedure if no clearance exists between the screw securing the lifter support to the cueing piston and the rubber button above it when the tonearm is parked.

The difference that perfect cartridge alignment has on playback sound quality in terms of stylus tracking, channel separation and soundstaging is not small!

I have created some documents which I have developed from the L-07D & L-07D II schematics and service manuals. These documents help me troubleshoot and repair these decks. All values and connections have been verified by me during service and repairs. [Information in brackets is/are replacement part supplier(s) and/or part number(s), see Links page for vendor contact info.] I have reproduced these documents below:

Heat Sink Compound also know as Thermal Grease for transistors on heat sinks: DowSil (formerly Dow Corning) 340

R192 47K (Late model L-07D and all L-07D II only on underside of PCB in circuit from IC10 Pin1 to C115)

R193 47K (Late model L-07D and all L-07D II only on underside of PCB in circuit from IC11 Pin1 to C117)

C101 22pf Ceramic [Allied 507-0201], [Radio Shack 272-809], [Mouser 594-CN15A220J]

C106 0.033uf Mylar (Larger than C124 and C125, probably higher voltage) [Allied 862-2206]

C107 4.7uf Tantalum (Tantalum capacitors are polarized with + and – leads) [Allied 852-5651]

X-tal L77-1101-05 labeled 5.5296 1101-0 TKC-H Schematic Lists X-Tal as 5.5296 MHz

Q15 NECD586 aka 2SD586 (60 Watt Power Transistor 5A/100V/15Mhz Silicon NPN) TO-3 [Obsolete]

Q18 NECB616 aka 2SB616 (60 Watt Power Transistor 5A/100V/15Mhz Silicon PNP) TO-3 [Obsolete]

PH 1 10 pin connecting post. Uses wire wrap posts spaced 0.10 inches apart (Standard IC connector spacing) On L-07D II round leads in white connector spaced 0.10 inch apart.

PH 2 6 pin connecting post. Uses wire wrap posts spaced 0.10 inches apart (Standard IC connector spacing)

PH 3 11 pin connecting post. Uses wire wrap posts spaced 0.10 inches apart (Standard IC connector spacing) On L-07D II round leads in white connector spaced 0.10 inch apart.

PH 4 2 pin connecting post. Uses wire wrap posts spaced 0.10 inches apart (Standard IC connector spacing)

1. Interrupt original top trace between (Right/IC8 side of) C115 and Pin 1 of IC 10

2. Solder in 47K resistor on underside of board from (IC8 side of) C115 to Pin 1 of IC 10

3. Interrupt trace on underside between solder point under R120 to solder point under the number “6” of Q6

4. Solder in 47K resistor between solder point under R120 and solder point under the number “6” of Q6

5. Solder in Jumper on underside of board from Pin 10 of IC 8 to (Left/IC8 side of) C117

R416 6.81K (1% Tol) (Incorrectly listed as 6.18K on page 4 of L-07D II service manual)

C401 10,000uF 35V 85degree ELNA CE69W(P) 40mm Diameter x 30mm Height, 4-Pin PCB Mount

C402 10,000uF 35V 85degree ELNA CE69W(P) 40mm Diameter x 30mm Height, 4-Pin PCB Mount

[BHC ALC10C103EC063 from RS Components part no. 339-8114, available through Allied telephone sales], [Kemet ALC10C103EC063, Mouser Part Number 80-ALC10C103EC063]

C411 0.01uf Polypropylene Across-the-line RFI Suppression Line Filter X-Capacitor [Vishay F1772 Class X2]

D401 Hitachi U05B Glass Bead Rectifier Diode 100V [Radio Shack 276-1143, 3A, 200PIV for 120VAC USA only use]

D402 Hitachi U05B Glass Bead Rectifier Diode 100V [Radio Shack 276-1144, 3A, 400PIV for 120VAC - 220VAC international use], [Mouser 863-MR854G]

Beware of factory defect PCB that is missing R4!!! Unit will intermittently not quartz lock at 33 RPM!

C5 0.1uf 25V Ceramic [Mouser 80-C052C104K5R molded or Allied 926-3418 ceramic] [Vishay Cera-Mite HY850]

D1 W06B [NTE-116] (Low Power switching 600V general purpose Silicon rectifier diode)

Now obsolete Asahi Kasei Microdevices (AKM) HW-300A Hall element sensors were made in multiple Ranks (or specifications, or types) of millivolt outputs ranging from Ranks A-H. The higher the letter rank, the greater the millivolt output. Ranks in the datasheet noted above are for Ranks A-F. The correct subtype for the L-07D motor is Rank A, which may also be referred to as Specification A or Type A. The Hall elements may have the letter of the Rank visible on the Hall element itself. The best match to the original will have the letter A visible on the Hall element, signifying that it is Rank A.

Note: Hall elements used in the motor are SMD's (Surface Mount Devices). A low-voltage soldering station with a very fine-tip iron, and magnification, are recommended for Hall element replacement work. Trim Hall element leads to length of original before soldering. This task requires advanced soldering skills. A dot on the Hall element signifies lead 1. Make sure to orient the Hall element correctly when replacing!

Obsolete Rank A Asahi Kasei Microdevices (AKM) HW-300A Hall element sensor shown above.

If you decide to use Rank or Specification B Hall elements (which have a higher output voltage than Rank or Specification A Hall elements), I would replace the Hall elements in pairs so that both Hall elements will be producing the same voltage. I have heard from another technician that after doing so replacing both Hall elements with Rank or Specification B Hall elements, that when the unit was sitting stationary at idle with platter not rotating that there was slightly over 2v across the Hall devices. Looking at the HW-300A spec sheet, that's slightly above the rating curve and after replacing the 820Ω R186 driving resistor with a 1K resistor, there was about 1.7v across the Hall sensors at idle, which is acceptable.

Once quartz lock is attained, the coils only get energized alternatively; i.e. coil A on, B off and vice-versa.

This ensures a smoother motor operation as now the rotational energization is passed on from one star tip to the next in succession.

This table lists the next point in the continuity chain for each IC pin. Use this list to check for open circuits before/after IC replacement. Also use to check any IC’s previously replaced. For resistors and capacitors, a continuity tester will read continuity on only one side of the resistor or capacitor. If a continuity tester reads open circuit on both sides of the resistor or capacitor, that would indicate a fault (open circuit). Always check adjacent pins on IC’s for shorts due to soldering. I prefer to use sockets when replacing IC’s. I prefer low profile IC sockets. On a good board, the solder will flow through from bottom to top and catch the top trace. Use flux on both top and bottom traces. Solder wick works best for de-soldering.

This list was made based upon schematics in the service manual and large schematic, and verified with continuity tester testing on a properly working PCB.

IC8 Pin 2 C115 (other side of C115), IC10 Pin 1 (on Logic cards without R192 &R193)

IC10 Pin 1 SC-1 Gain (VR-3), C115 on , IC8 Pin 2 on on Logic cards without R192 &R193

The following continuity information is useful for tracing problems in the umbilical between the Control Unit and the Turntable connector. This information is also useful if a bad connection or adjacent connector short occurs inside the main connector, and a wire needs to be directed to a different pin:

Inside the X25-1550-00 Connector PCB receptacle, the 24 pins are defined in four rows labeled A through C and six columns labeled 1 through 6.

Inside the X25-1550-00 Connector PCB receptacle, the following pins are in continuity:

Unit starts without pushing operation button, speed indicator momentarily hits GREEN but continues to speed up and stays RED, pushing operation button does not stop unit – Bad IC2.

Solenoid clicks when powered up at 33 rpm before operation button is pushed. If operation button is pushed (at 33 rpm) unit will quartz lock. If operation button is pushed again, unit will stop and solenoid will resume clicking once platter stops. If switched to 45 rpm, unit will turn backwards and will not stop when operation button is pressed again. - Bad IC 2.

Unit starts but speed indicator never turns GREEN, platter over-speeds. Operation button slows platter with much less force than normal - Bad IC 2.

Unit starts and quartz locks normally at 33 and 45 rpm. When operation button is pushed mechanical brake chatters (Solenoid clicking) and works ineffectively. Mechanical brake chatter stops when platter stops. - Bad IC 2.

Unit powers on normally with platter motionless before operation button is pushed. Engagement of solenoid brake occurs almost silently at power-up, without the usual audible click. Unit will quartz lock when operation button is pushed. When operation button is pushed again, platter will slow to a stop and then continue to rock back and forth, brake solenoid doesn't deploy. Pushing operation button again, unit will play and quartz lock, but same phenomenon when the operation button is pushed again; platter will slow to a stop and then continue to rock back and forth, brake solenoid doesn't deploy - Bad IC 3.

Speed indicator flashes RED-GREEN, runs at correct speed but won’t quartz lock – Bad IC 6.

When the Operation button is pushed, the platter gradually increases speed but over-speeds. Speed indicator doesn’t turn GREEN. Pushing the Operation button again results in platter stopping a few minutes later (Mechanical brake correctly activates with click sound and platter stops) - Bad IC 7.

Motor buzzing when platter is stopped due to electronic brake remaining on - Bad Q23.

Platter gently rocks back and forth at startup, but will not spin. If started with a push, it will spin but will not quartz lock - bad C102.

Speed indicator flashes RED-GREEN and depending on the position of the rotor platter will start alone or just rock backward and forward - bad C119 allowing DC on the B winding.

Unit goes to hyper-speed, speed indicator never flashes GREEN. Brake works properly – Bad L1 and L2 inductors on X25-1550-00 Connector PCB.

Unit occasionally won't quartz lock at 33 rpm - Check for factory defect in X25-1550-00 Connector PCB. I have found one made without R4.

Unit starts and plays normally. Only problem is clattering sound from motor during electronic braking. Braking function is otherwise normal. - Bad capacitors on X25-1550-00 Connector PCB. Replace 0.1uf Ceramic capacitors (2), replace and upgrade 10uf electrolytic capacitors (4).

Unit starts and plays normally. Only problem is mechanical brake engages as soon as Operation button is pushed to stop platter rotation. Braking function is otherwise normal including electronic braking. (Mechanical brake is not supposed to engage until electronic brake has slowed platter to 1/5 of operating speed,) – Bad IC 2.

Platter over-speeds momentarily for about 1/2 turn (kick) before it returns to lock mode. This happens every 10-15 sec.– Bad front Hall element.

Rubbing sound in motor - Possibility #1: Magnetic pad has de-laminated from underside of rotor. Do not run unit until repairs are made. Possibility #2: Thrust bushing wear has allowed magnetic pad on underside of rotor to rub FG Coil PCB screws. Repair by disassembling thrust bushing mechanism. Flip bushing over to expose unworn side and reassemble with a new O-ring and lubricate bearing. Do not run unit until repairs are made. Possibility #3: Stator coil wires rubbing against the rotor. Repair by gently pulling all wires exiting the motor thereby removing slack in all wires. Do not run unit until repairs are made. Possibility #4: Rotor is contacting some portion of stator. Repair by inserting a brass washer shim between each stator screw bushing and the motor housing to increase clearance between rotor and stator. Ensure that each motor cover screw will pass though a brass washer shim to hold the shims in place after reassembly. Do not run unit until repairs are made.

When the unit is powered up, both speed indicators (33 & 45 RPM) are on at same time (RED) instead of one. When the speed button is pressed, 33 RPM speed indicator turns off, 45 RPM speed indicator remains on (RED), press the speed button once again and 33 & 45 RPM are again on at same time (RED). (45 RPM speed indicator never turns off.) Unit will only play at 33RPM, either with speed indicator reading 45 RPM quartz lock (GREEN) but actual speed is 33 RPM, or if speed button is pushed will again quartz lock at 33 RPM with both speed indicator LEDs staying on at the same time (33 & 45 RPM speed indicators both (GREEN). (45 RPM speed indicator never turns off.) – Bad IC 301 and 302 on switching PCB.

PLL waveform not stable, noise in AC signal driving the motor - Bad 0.001 uf capacitor.

Intermittent quartz lock failure - stray strand of wire from jumper on undersurface of logic card intermittently making contact with adjacent component lead solder point.

From Nick Gorham: Internally they were untouched and in good condition, but on powering up the control unit the platter started to rotate at 33RPM, running perfectly, but switches had zero effect and none of the LED's lit. After trying all the obvious like checking the connecting cable. I eventually removed the switch PCB and running it on a bench supply is wasn't working. Replaced IC301 and 302 but made no difference. Finally traced the fault to be broken earth/0v continuity as the trace went to and from R301. I can only assume the board had flexed and broken the trace. added wire links to mimic the traces to and from R301 and then it worked as expected on the bench. Replaced it into the turntable and it all works fine. Checked setup, it was almost perfect so left well alone. Power rails were +- 27v so again the transformer was never a good match for UK supply which while officially 230v, it almost always over 240v (mine is 246 normally).

Unit quartz locks but the motor buzzes intermittently when stopped. Disconnecting the mechanical brake makes no difference, confirming that the buzzing is from the motor. This occurs intermittently for around a second at a time. It is most notable just after turning the Control Unit on. Thereafter the occurrences happen anywhere from minutes to hours apart. Occasionally, the platter will turn backwards a small amount when the buzzing occurs, but not usually. Changing the position of the Dynamic Parameter Switch makes no difference. The buzzing occurrences are seen as positive voltage spikes at test point (TP) SC2 and as negative voltage spikes at TP TPR. No voltage spikes are seen during occurrences at TP SC1, however. Below are some DSO images of the occurrences sampling from TP SC2:

The fault was a bad signal transistor, one or more of Q1, Q26, Q27 and Q28, all of which I changed out together. The bad transistor(s) tested good in circuit but had the failure under power. At some point, Kenwood replaced the 2SA733 amplifier transistor at Q26 with a 2SA921 high-gain amplifier transistor. I wonder if they saw similar or different issues with Q26 that caused them to make this change. When I see a unit for service that has a 2SA733 at Q26, I replace it with a 2SA921 equivalent (NTE 91):

Unit turns at set speed but playback sound has speed instability. This can occur with or without a rubbing sound from the motor. On the oscilloscope, there is instability of the PLL waveform sampled at TPR (video links below). There is also similar instability of the square wave sampled at TPF.

With the turntable operating at 33 RPM, the waveform instability occurs 33 times per minute.

With the turntable operating at 45 RPM, the waveform instability occurs 45 times per minute.

The cause of this fault is a delaminated and eccentrically-shifted magnetic pad on the underside of the rotor. The magnetic pad remains adherent to the rotor plate due to magnetism. The glue bond has failed and the magnet has shifted to an eccentric location on the rotor plate as shown in the photo below:

The photo below shows that the glue that bonds the round magnetic pad to the rotor plate has failed.

It is easiest to test the logic board transistors after removing all the capacitors at the time of capacitor replacement.

When servicing the power supply board in the Control Unit, the board will need to be turned between top side up and bottom side up a number of times to replace caps, rectifiers, etc. This will put repeated strain on the wiring from the transformer to the power supply board and the wiring from the mains in to the power supply board. To prevent this wire strain from occurring and causing wire breakage, turn the transformer with the power supply board each time. Otherwise the repeated strain will cause wires to break at their solder points.

When recapping the power supply board, it is easiest to use a spring clip heat sink on the small capacitors when soldering in replacements if the front 10,000uf filter capacitor is off the board, i.e. removed and before the new replacement filter capacitor is soldered in.

Due to some thin traces, some logic PCB traces most prone to trace damage during capacitor removal: C114, C116, C115, C117 in particular. Extra caution and gentle technique for desoldering and removal are recommended for these logic PCB caps. Cap splitting, shown and discussed below, can help minimize the chance of trace damage during capacitor removal.

Trace damage that occurred during removal of C116 without splitting the cap first is shown above. Trace repair can be done by exposing the copper on the remaining end of the trace for 3-4 millimeters and soldering wire from the trace to the replacement capacitor pin, or with a jumper wire on the bottom of the PCB.

The small paper capacitors (C118, C119, C120, C121, C122, C123) are easier to remove, and removal is less likely to cause PCB trace damage, if they are split vertically in two before removal. Then the individual pins can be pulled axially during removal without having to cant the cap sideways during removal.

In the photo above C119 has been vertically split with a 6 inch cutter prior to removal.

In the photo above, a removed split 0.001uf paper cap is shown with small cutters used to split the cap.

The larger paper caps on the logic board (C114, C116, C124 and C125) are easier to remove, and less likely to cause PCB trace damage, if they are split vertically in two before removal. These caps require a somewhat larger cutter than the 0.001uf paper caps. The double-action 8 inch cutter shown in one of the photos below works well for this purpose.

One of the larger paper caps on the logic PCB (C124) is shown vertically split in the photo above prior to removal.

The 8-inch double action cutter shown above works well for splitting the larger paper caps on the logic PCB prior to removal.

For integrated circuit removal, PCB traces are much less likely to be damaged if the IC pins are cut from the IC body, and then the IC body removed, prior to IC pin desoldering and pin removal from the PCB.

Shown in the photo above, the IC pins were cut off from the body of the IC right where the pins exit the body. Then the IC body was lifted away from the PCB. After doing so the IC pins on the PCB are fully accessible for individual desoldering from both sides of the PCB.

Logic PCB shown above after removal of all paper and film caps with no trace damage.

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