AIWA HS-JX70/HS-RX70/HS-JX707/HS-JX707D/HS-JX3000/HS-JX3000D/HS-JX909/HS-JX828/HS-JX929/HS-PX70/HS-PX1000 These units are very similar to each other (although not identical), all sharing the 0ZM mechanism. The only one from the series that's significantly different from the rest is the HS-PX70 (but it still shares the transport). NOTE: after some testing, I realised the FixYourAudio belt for this unit is too loose (74mm) and will slip under FF/REW. Hence why I recommend buying a 70mm belt instead: https://fixyouraudio.com/product/rubber-belt-70-0-6-mm-square-shaped/ Repair and maintenance items: - leaky capacitors need to be replaced and board thouroughly cleaned; - all switches (including the 2 x FWD/REV ones) and volume potentiometer must be thoroughly cleaned with contact cleaner; - a full re-lubrication of the mechanism is necessary, including a re-lubrication of the motor; - microcontroller backup battery will need to be replaced; a VL1220 NiMH cell can be used for replacement; - flex cable between main PCB and door PCB can break, symptom being no power and nothing displayed on LCD; - the 2 pins that hold the pinch roller brackets may be bent, causing the rollers to sit at an angle relative to the capstan. In such case, they will require straightening. - the head bridge may be bent, causing the head to sit at an angle. It will require straightening. Common capacitor values: 220uF@4V SMD, 100uF@4V SMD, 47uF@4V SMD, 220uF@4V THT NOTE: capacitors are very small (5mm height) and modern ones with the same ratings likely won't fit, hence why I recommend using SMD tantalums (including THT ones).
Toshiba KT-AS1/KT-AS2/KT-VS1/Kenwood CP-10 These 2 walkmans are almost identical, main difference being the KT-AS2 has only 1 headphone jack, hence the cases and PCBs not being interchangable. The KT-VS1/Kenwood CP-10 use a similar mechanism, but without auto-reverse. They shares similar problems. Repair and maintenance items: - table reel gears are cracked on these units and will need to be repaired; - table reel retainers are cracked and will need to be repaired as well; - a general cleaning and re-lubrication of the mechanism is recommended; - Dolby/EQ switches and volume potentiometer will need to be cleaned with contact cleaner; - Dolby levels might need to be adjusted for proper Dolby decoding; Levels are 100mV RMS with 200nWb/m ANSI test tape at pins 4 and 13 of the NJM2063 IC. For repairing the broken gears, what needs to be done is enlarge the hole with 1.6mm drillbit then glue the gear back to the shaft. For the retainers (which must be done first), the hole must be enlarged with same 1.6mm drillbit, but also they must be marked relative to the reel (as the hexagon is eccentric). Reatiners might also need some filing on the edges of the retainer hexagon in order to move freely up and down. NOTE 1: The reel must move up/down just by the force of small spring, so be very careful to first put the retainer into the reel, then add glue, otherwise you will glue the retainer to the reel. Also put a very small amount of glue, using the tip of a tweezers or small screwdriver. NOTE 2: I recommend using liquid type super glue (like Loctite Super Bond), not paste epoxy type. Original belt for this unit is 1mm thick, hence why I recommend the DeckTech belt for these devices.
Kenwood CP-E5/CP-E7/Sharp JC-K99 Kenwood CP-J7 Repair and maintenance items: - clutch gear broken, will need hole to be enlarged with drillbit and glued with super glue; - re-lubrication of the mechanism; - re-lubrication of motor; - cleaning of volume potentiometer, Dolby/EQ switches; Belt: 58mm x 0.8mm Belt (CP-J7): 70mm x 0.8mm Pinch rollers: SONY WM-700 series rubber tires
Philips DCC130 Repair and maintenance items: - leaky electrolytic capacitors will need to be replaced; - belt needs to be replaced; - pinch rollers may need replacing depending on condition; Belt: same as DCC170: https://fixyouraudio.com/product/belt-philips-dcc-170/ NOTE: Portable DCC units use a Panasonic AR90 mechanism, so any Panasonic RQ-S belt will fit. Capacitor values: 220uF@4V SMD (2pcs), 100uF@6.3V SMD (3pcs), 47uF@4V SMD (2pcs), 47uF@16V SMD (1pcs), 22uF@6.3V SMD (1pcs)
Panasonic RQ-S series (first generations AR90 mechanism with pad lifter head carriage) Models affected are manufactured between 1989 and August 1992: RQ-S1, RQ-S1D, RQ-S3, RQ-S5, RQ-S5V, RQ-S7F, RQ-S7R, RQ-S8, RQ-S4, RQ-S6, RQ-S11, RQ-S33, RQ-S55, RQ-S88, RQ-S55V, RQ-S45, RQ-S65, RQ-S77F, RQ-S15, RQ-S35, RQ-S35V, RQ-S75F, RQ-S60, RQ-S60V, RQ-S80, RQ-S20, RQ-S40, RQ-S40V Main problems with these walkmans are bent pinch roller bracket holding pins and bent pad lifter mechanism which will cause the following symptoms: muffled sound, L/R imbalance (due to incorrect azimuth), increased wow&flutter and a tape speed difference between FWD and REV that is out of specification. Secondary problems are related to lubrication: given the FWD pinch roller spring puts more force on the capstan, it's possible the bushing has wear. Re-lubricating the motor, capstan bearings and main pulleys is a must on these units. It is to be noted that wear on the bushings will increase the w&f figure. This is true on both older and newer AR90 mechanisms. Maintenance items are as follows: - repair of bent pinch roller pins; there will be an upcoming thread covering the repair which will be linked here. - repair or disable the pad lifter; - reducing the force of the pinch roller springs and also making them equal for FWD and REV; - lubricating the pinch roller pins and the pinch roller bracket holding pins; - general re-lubrication of the mechanism (motor, capstan bearings, main rotating parts); - installing a new belt; - replacing the pinch rollers if necessary; - cleaning of switches and volume potentiometer; While restoring these walkmans is straight-forward and doesn't require any spare parts apart from new rubber, aligning the pinch rollers perfectly, reducing spring force and fixing the pad lifter are all critical for good operation. Compared to later generation RQ-S (which should only require a belt swap + lubrication), these are a bit more involved to restore.
Panasonic RQ-X series These mechanisms are different than RQ-S or RQ-SX series, not sharing anything in common with them. Repair and maintenance items are as follows: - repair of the clutch retainer (it needs to be cleaned and glued); - cleaning the mode switch; - re-lubrication of motor and capstan bearings. Rotor of the motor simply pulls up; - installing a new belt; - replacing the pinch rollers if necessary; - potential problem with PCB vias. More info here: https://stereo2go.com/forums/threads/panasonic-rq-x11-repeating-reverse-error.7496/#post-55517
Panasonic RQ-P580/RQ-P500/RQ-P515/RQ-P525 (uses 3-phase brushless motor) Panasonic RQ-JA150/RQ-JA155/RQ-JA158/RQ-JA160/RQ-JA170/RQ-JA180 (uses DC brushed motor) These 2 walkman series have 2 types of mechanisms, one with 3-phase brusheless motor identical to the ones at post #43, second with DC brushed motor. However, they both share the same common problems. Repair and maintenance items: - replacement of clutch. Unfortunately this clutch cannot be repair and must be replaced; - re-lubrication of rotating parts; - replacement of pinch rollers. Very specific pinch rollers are used and they need to be replaced as a complete assembly roller + hub as original hubs shrink; - leaked batteries are common. Some of these walkmans have carbon printed resistors and PCB repair might be needed. - cleaning of volume potentiometer and switches; NOTE: Can't recommend any source of replacement clutches at this point. Thread will be updated at a later date. Belt: 74mm x 1mm (inner diameter x thickness) for mechanism with DC motor 58mm x 0.8mm (inner diameter x thickness) for brushless motor
AIWA PL30/303, PX30/PX303, PX50/505, PX900, JX30/303, PL50/505, HS-F505, HS-JL30/303, HS-PL55/555 These units are very similar, sharing the Alpha-2 mechanism and grooved head. Repair and maintenance items are as follows: - leaky SMD electrolytic capacitors. Pretty nasty leakeage typically, not uncommon to find open vias; - it's highly recommended to desolder, clean and resolder the main ICs affected by corrosion: pre/power amp (TA8115F), Dolby ICs (2 x NJM2065), microcontroller (TC9311F-014); - all switches on the PCB and potentiometer need to be throroughly cleaned; - clutch retainer breaks, needing repair. https://stereo2go.com/forums/threads/aiwa-alpha-2-clutch-repair.10059/#post-81690 - re-lubrication of the rotating parts is necessary, including the motor; - re-lubrication of camgear and adjacent levers is highly recommended; - bent pinch roller holding pins and head bridge can happen. Needs to be checked with gauge and straightened if necessary; - Dolby levels needs adjustment; - azimuth needs to be checked/adjuted; Belt: 57mm x 1mm (inner diameter x thickness) Note the original belts are still good on most of these units and don't recommend replacing it unless it's loose or deformed. Dolby adjustments: 100mV RMS at indicated points (see service manual) with 200nWb/m ANSI test tape.
National/Panasonic RQ-KJ1/WJ1/SJ1/J2 All of these units are identical apart from the outer casing. The devices use a flex-type double sided PCB and Mitsubishi (CE marking) brand capacitors which are prone to leakeage. Repair and maintenance items are as follows: - leaky capacitors must be replaced; leakage is pretty nasty, expect damage of vias; - the entire PCB needs to be thoroughly cleaned and all the vias near capacitors checked for continuity and repaired accordingly; - main rotating parts of the mechanism should be cleaned and re-lubricated; - motor top bearing should be lubricated and belt replaced; - switches and volume potentiometer must be cleaned; Belt: 46mm x 1mm (inner diameter x thickness) Capacitor values: 220uF@4V THT (4pcs), 22uF@6.3V THT (1pcs), 47uF@4V THT (2pcs), 100uF@4V THT (2pcs), 4.7uF@25V THT (2pcs), 10uF@16V THT (1pcs), 470uF@6.3V THT (1pcs)
