This tutorial covers the restoration of older generation RQ-S series with pad lifter. 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-S15D, RQ-S35, RQ-S35V, RQ-S75F, RQ-S60, RQ-S60V, RQ-S80, RQ-S20, RQ-S40, RQ-S40V, RQ-V500 Some models without the pad lifter are also affected, like RQ-S90F. These require the same repairs, except the pad lifter since it doesn't exist. There are 3 main problems on this mechanism: 1. Bent pinch roller bracket holding pins, which will make rollers sit at an angle. Note both rollers are affected, despite some people say only the FWD one needs repair. 2. Bent pad lifter. This can be straightened and reinforced or disabled. Since this pad lifter does have a purpose (to reduce tape/head friction during FF/REW), my recommendation is to repair despite disabling/removing it will seem the simpler solution. 3. Bent carriage. This is harder to adress and can cause head tilt problems. Not adressed at the moment in this tutorial, to be updated later. NOTE 1: It's very important to bend the 2 roller springs so the force is lower than in the original setup and also equal on both sides. Failing to do this will render: - the pad lifter to bend again in time; - tape speed and W&F be different FWD/REV; With a proper repair, the speed difference should be within 10-20Hz. If it's more than that, either one roller is putting more pressure on the capstan or one capstan bearing is worn, case in which mech needs to be replaced. NOTE 2: FWD capstan bearing tends to wear prematurely if unit is used without adressing this problem, since the FWD roller spring is much stiffer from factory. This is another reason why capstan bearing should be cleaned and lubricated. NOTE 3: It's very important to never leave cassettes in the unit when it's not in operation. The pad lifter sits in the raised position when mech is in stop position, meaning it will bend back in time if a cassette is left in the unit. NOTE 4: Recommend NOT replacing the pinch rollers on these units, unless it's absolutely necessary. That's because new rubber tires that are available will usually make the assembly eccentric. NOTE 5: Most of these units use a slim 220uF electrolytic capacitor, which sometimes can go bad causing increased motor hum. If you have the means to test it, do so. Otherwise it's a good idea to replace it. SMD tantalum is the way to go for the replacement.
DISASSEMBLY To be noted the case disassembly and PCB removal is for illustriation purposes only as this will vary from model to model. In pictures attached there is an RQ-S45. Case is usually held in by 4 screws, but some units have another extra on the back. On PCB, keep in mind the main things that need to be desoldered are: - motor (4 pins on all mechanisms); - solenoid; - negative battery terminal; - logic control buttons and tape in/EQ switches; - head flex (this needs to be desoldered for easy work on the carriage); Door is held the same on all units, having one screw and latch needing to be removed. On radio units, the door and PCB need to be removed together if you don't want to desolder the flex cables. Carriage is held the same on all units, you only need to remove one hinge for removal as shown.
CLEANING AND LUBRICATION OF MECHANISM Before adressing the carriage problems, first thing to do is clean all the pulleys from old belt residue and oil the main rotating parts of the mechanism: motor, capstan bearings, idler pulley, gear drive pulley. NOTE 1: Unlike most other walkmans, this Panasonic (and others Panasonic RQ-SX, RQ-JA) uses a full washer which needs to be dragged up the capstan in order to remove it. There are a total of 3 washers: a white one that holds the capstan/flywheel assembly, a black one underneath and another black one on the opposite side of the bearing. NOTE 2: Pulleys' grooves need to be cleaned thoroughly before re-installing the capstan/flywheel assemblies. There are 2 methods of doing this: - IPA + cotton swab for the soft residue and sandpaper for the hard part; - gasket cleaner (Loctite SF7200) + cottom swab; if gasket cleaner is to be used, be careful to clean everything with IPA after, as it will dissolve rubber; NOTE 3: Depending on serial number and model, just one flywheel has a retainer, some have retainers on both, while some none. This retainers aren't critical since the capstan is held in place by the washer. So process goes as this: - remove one capstan/flywheel assy, clean the grooves, clean the bushing and caspstan shaft. - add oil on the bottom part of the shaft and/or inside the bushing and re-install the assembly; - clean the extra oil with a piece of paper towel; - put the washers back; - clean the capstan with IPA; Note it will need further cleaning after operation; Motor lubrication is not shown, but process is similar to SONY ones shown here: https://stereo2go.com/forums/thread...-type-motor-in-sony-walkmans.7943/#post-59754 What's to be noted in this case is the coils PCB tends to be stuck to the brass posts. For this, remove the motor from chassis and heat the posts with soldering iron for easy removal.
CARRIAGE REPAIR This is the most tricky part of the repair and all steps must be followed exactly for best results. 1. Remove both pinch rollers and pad lifter from the carriage. 2. With a small pair of pliers bend the FWD pin until it becomes straight by eye. Note the pin will have significant play now. Don't worry, this is normal. 3. Install the FWD roller back, but WITHOUT the spring; 4. Engage the mechanism into FWD; 5. Install the carriage back and test alignment visually; 6. Repeat steps 2-3 until you get perfect alignment; 7. Glue the top of the pin while making sure the alignment remains perfect. Keep the roller pushed with your finger if needed until the glue starts to cure; 8. Double check the alignment. If good glue the bottom part of the pin as shown in pictures. 9. Let the glue cure and check the roller can rotate freely on the pin. If not, carefully remove the extra glue with a pair of tweezers. 10. Engaged REV on the mechanism as shown in pictures. Remove the cassette holding part on the opposite side for good visual path to the roller/capstan. Note the pad lifter and roller spring do NOT get installed at this step. 11. Repeat same steps as FWD pin until you get a perfect alignment. Note this side can't accomodate as much glue due to the pad lifter arm. 12. Bend the pad lifter so it become flush with the head again. Note both the holder part and the arm need to be bent. 13. Install the spring and roller and make sure the pad lifter moves back and forth easily, returning just by the force of the spring. 14. If everything is good, add glue on the 2 spots shown in picture to reinforce the pad lifter. 15. Bend the roller springs back so you reduce the roller tension. 16. Double-check by hand and re-adjust so force is similar on both sides. 17. Put the mechanism back into stop position (lever in the middle). 18. Re-install the carriage.
@Valentin, great tutorial! I really admire the design of this model series, they cram an awful lot into that tiny case size, yet the construction is elegantly simple (at least compared to some Sony models I've worked on recently). They sound great too! I’ve just finished doing the pinch roller pin realignment on a RQ-S11 with good results. I heated each pin with a (dry) soldering iron while applying pressure, to try to soften the plastic housing around the base of the pin. It's a hard plastic with a high melting point, but I think this did help a little although they still ended up quite loose. I did the alignment by eye, setting the pin parallel with the edge of the plastic housing, then wedged a piece of cocktail stick behind each pin to hold them in position while gluing them in place. I've also done as suggested and bent the tension springs to reduce pinch roller pressure. I agree it seems excessive in its original state, reducing the pressure eases the load on the motor, and I'm not getting any slippage. Good call!
Thanks for this!!! Exactly what I needed to see. What is the best, reasonable, W&F one should expect from this transport?
W&F obtainable on these units will depend a lot on capstan bearing wear and can vary anywhere between 0.15% WRMS (a best case scenario) to 0.30% WRMS or even more if there is a lot of wear on it. This is all assuming the roller alignment is perfect, spring tension is matched and lowered on both rollers, rollers are in good condition (no eccentricity, rubber still soft, no indentations). Due to the fact the FWD roller spring is stiffer, there tends to be more wear on that capstan bearing, especially when the unit was used a lot before a restoration was performed. This can lead to a situation where FWD W&F is double of REV figure for example, case in which the mechanism may need to be replaced. There can be situations where a mechanism swap is necessary to obtain reasonable W&F figures.
Yes the bushings are replaceable, but I highly doubt there are many who actually have the right tools to replace them. Not to mention the spare parts, which would need to be custom made. As a sidenote, there's no need to quote previous posts. Please type in the box below and use the "Post Reply" button instead.
Excellent tutorial @Valentin thank you for all the effort you put into this! Now i'm worried about the Panasonics that are coming my way, lol S1, S3, S11, S15, S33 But once fixed do they stand their ground? They look high end but how do they sound once serviced?
Yes once fixed they do stand their ground. Only important thing is to not leave cassettes in, as that pad lifter will have extra tension from the cassette pressure pad. Good part with spring adjustment and reinforcement of the lifter is at least it won't bend back just by staying in storage. Then the one big potential problem is capstan bushing wear, which I've seen high-end models like S60 and S80 are much more likely to have. These walkmans do sound good, however they're not tuned all the same some rendering better sub-bass response than others. Also S-XBS tuning is not the same.
Ok thanks, weird about sub bass response, usually lack of bass means crap caps....but there are hardly any service manuals for any of these... edit: and i never ever leave cassette's in any of my decks, never did. After listening fully rewound back in cassette shell and back in dark dry drawer....i love my cassette's
It's not about crap caps, but different value components for different tuning. It's a design choice. SONY did similar thing on many units including with DBB/MegaBass tuning. Likely has to do with the fact they wanted some units to sound more "analytical" (mid-range focused), while others to sound more fan (with better deep bass). What Really Happened to Aiwa - YouTube This video suggests a similar thinking in AIWA vs SONY units. This can be modified but without service manuals it is a bit hard to find the components you need to replace.
