Hi, I recently purchased a Panasonic RQ-SX52 cassette Walkman in decent shape, it just needed new belts and a new clutch. Here's a picture of what one looks like: So, I replaced all the belts and that clutch, but when I went to play it, it sounded absolutely terrible! The speed was correct, but it had this very fine flutter to it, and when I shake the unit or go to move the unit and walk with it moderately, the wow/flutter gets much worse. So, I took the unit apart again to verify the belts were on correctly, and I double checked to make sure no gears were stiff, stuck, or cracked. Also, I double check enough grease was present. I also checked out the pinch rollers and capstans and they seemed to be fine... So, this unit just plays really badly, and it doesn't seem to be because of a fault, more of a design issue. Does anyone have any experience with this model, or the RQ-SX series?
I had the same experience with RQ Panasonics: nice-looking thingies but unless it has matt capstan and fresh pinchroller (thankfully, now available from @mihokm ) the tape is not pulled properly. Pinchroller is as wide as a tape, so the only thing that guarantees correct speed is capstan abrasiveness against the tape, which is pretty slippery
It has a matt capstan, but the pinch roller is kinda dirty and smooth (not fresh at all). Now, it's acting funny electronically sometimes stop will make it auto reverse or just shut down. I just hate this thing. It seemed so promising but now not at all. It seems all of these 'works in the door' walkmans with thin pinch rollers and cheap mechanisms easily develop problems.
Ok, So I've officially determined that the Panasonic RQ-SX series is NOTHING but junk. Buy why? This: This is the main flywheel who's belt connects directly to the motor. First problem is this flywheel weighs practically nothing. The weight and placement of the flywheel in a Walkman is what protects the speed and pitch against jolts. And since this flywheel IS so light, every step and jolt is felt. The second problem is the gear on the bottom. This gear connects the flywheel with the ENTIRE rest of the mechanism. This gear shrunk and is cracked in three places. (very similar to the Walkman DD problem) This causes VERY harsh wow/flutter and noise in the mechanism. But I take back my statement that all "works in the door" Walkmans with thin pinch rollers are problematic. I got a WM-EX77 now that has a very heavy flywheel for such a small Walkman and has VERY low wow/flutter. But the EX77 specifically boast great stability and was from '92. My RQ-SX55 is from 1997. Here's the SX55:
I am having a very similar problem with an RQ-sx60 I recently bought: replaced belts, fixed clutch and it plays horribly with high W&F. I have not taken apart the flywheels as I do not feel confident doing it, so i cannot tell if the gear is broken. The transport is noisy when in playback, but oddly enough is more silent when in FFW or REW. Should I throw in the towel and keep the walkman only for semi-static display ?
There are three reasons for this: 1. The new belts are two thin to sustain the force it takes to drive the tape. This can be easily spotted by simply monitoring the belt for any wobbling while playing the tape. This is especially likely if you have the two belt model. 2. the pinch rollers are bad. If the pinch rollers are dry, have a plat place, or are too oxidized, then they will not grip the tape properly/capstan properly. For good measure, I usually just replace them. 3. Either a gear is cracked/spread apart, or there is insufficient lubercation. Try lubing the gears, but don't go crazy with the grease. Use a tooth pick to apply small amounts. If any noise persists after lubercation, you have a gear somewhere in the mechanism that no longer has the structural integrity to support the drive mechanism. In any case, I've owned two of these, and I hate them. While they are very beautiful to look at, they are cringy to listen too. You can try and diagnose the problem using what i've learned, but even still, you probably just need to move on sadly.
Thanks for the suggestions, belts are new from Marian, they have the specified thickness of 0.5 mm; I tried adding tiny bits of Molykote UML-30 grease to the high speed gears (the ones driven directly by the main capstan) and that helped to decrease the noise of the transport and also playback in the reverse direction (the one driven directly by the motor) is decent, almost tolerable. Playback in the forward direction is still cringy and I think also a bit slow. Capstan are in good shape, they both have two rougher "bands" to increase grip on the tape and pinch rollers are fine. Honestly looking at the tape transport I keep asking myself what were they thinking: considering it is supposedly Panasonic high end walkman transport, I cannot find and good point in that design. It simply cannot perform better than a standard single belt transport, it is bound to be inferior. Other cheap and made of plastic walkman's do have much better transport stability, even the one with plastic flywheels. I do not know if you are familiar with the RQ-SX60, it has a decisively over-engineered cassette lid, which fold in two when open to give access to a large part of the cassette shell. Insanely complex and pretty pointless. Couldn't they spend those resources into designing a better transport ? I knew from the start it wouldn't have replaced my Sony daily driver walkman, I was just hoping to have it run decently, but I guess that is as good as it can get.
Yes, I'm very familiar with that lid design. My SX-55 had the lid that splits in two. It has a very good point. It allows the lid to shrink so you can grab the tape easier. Don't ever disassemble it! Took me four hours to re-attach the two springs on either side of the door. I do agree with you that they should have spent a lot more time on the mech than the cassette door! I agree with you, the mech is awful. I had the same issue, one direction was horrible, and one was ok. It was that flywheel gear that had spread apart that was the issue for me. I also have some really cheap Walkmans that could beat the any SX two belt unit. I think the problem was they tried to make it thin, and they didn't spend enough time on the design mechanically. Also, look for the unit's solenoid to fail too, the symptoms of this are: 1. Cannot stop tape once in playback (unit instead shuts down). 2. No rewind fast forward 3. short series of beeps when you try to press anything.
I guess my RQ-SX60 has the same issue with the plastic gear underneath the main flywheel; sandwich gears with a metal core and plastic crown are destined to break; I have many examples of that happening on different units. If the plastic ring of the clutch broke, it is fair to assume the flywheel gear is cracking too (though from the outside I do not see any cracks); even if not cracked, teeth have shrunk and contact with other gears is noisy and less accurate. Solenoid still works ok; if that breaks nothing works indeed, the transport is stuck in the last mode it was able to set (the main cam gear has three positions, FWD play, REV play and FFW/REW/STOP). As for the thickness, I compare the RQ-SX60 to my Sony WM-EX672. The latter is slightly smaller, same thickness and it has a far better and more reliable transport with an easy to access belt. Sure it does not have a colour LCD remote, but who cares when sound is horrible.
Yes, when the solenoid fails, the unit will not work at all, but my solenoid in both of my SXs were weak. The SX-52's solenoid was so weak it would only work maybe 1 out of 7 times. The SX-55 would work 1 out of 3 times. This was very frustrating and made the unit exhibit that famous 'mind of its own' problem, where anything could happen and gremlins were real. This was fairly consistent across both of my units, although the SX-55 was in earlier stages of the problem. True, I've owned a few WM-EXs over the years, and when I saw the mechanism of the EX for the first time after coming from the SX, I weeped with mechanical joy. The cam gear is so solid in the EXs. In particular, I like Sony's 1992 offerings (ex-66, ex-77, ex-88). The EX672 is a great unit to compare with your panny, since they are contemporaries of each other, and were probably competitors back in the day.
The strength required by the solenoid is minimal, when manually cracking the tape transport to understand how it works, just a gentle push with a finger nail is enough to set the cam gear in motion.What I did not fully understand is how the unit knows in which mode it is set; there is no mode switch so I guess it just counts the solenoid pulses assuming it always start in the correct position, but it is quite a strong assumption. The WM-672 does feel a tiny cheaper than the RQ-SX60; the Sony is already on the downhill slope from the high quality models of the early mid 90's to the desolation models of early 2000's. More plastic, gone are the brass flywheels and the overall finishing quality is not top notch. The Panasonic is great to look at, feels very solid and well built, but the terrible transport is a huge downer. The RQ-SX is also designed to be used with the remote, the buttons on the player body are more stylish than useful; the Sony has a more rational buttons placement and there is tactile difference between play and stop buttons.
On further inspection, I noticed the direction that has lower W&F is indeed the forward direction, the one driven by the two belts ... That is quite odd. As I had to fully take apart the motor to clean it from melted belt, the two magnetic discs needs to somehow aligned when re-assembling the motor ?
Good question! No alignment is necessary, the powerful magnet should self align the disc on top of the motor coil. You just have to be careful taking it off and replacing it to not damage any of the coils. Excessive prying, or fiddling will cause permanent damage to the coils. Hmm... the speed issue doesn't seem odd to me. The forward direction's flywheel isn't connected to any gears, so no stability issues in the rest of the mechanism can effect its rotation. Also, that second belt absorbs more changes in energy, since it is longer. ...for the other direction, the flywheel itself is directly connected to the entire transport mechanism by gears, so it has to drive the capstan, plus handle the brunt of the reel resistance in the tape casing. Put this together with the tiny, thin belt connecting it to the motor, and that equals problems. This is it in a nut shell: observe both flywheels, one is completely independent, and the other does three jobs at once with a smaller belt (which is more prone to stretching and slipping and absorbs less shock) driving it. This is why you have the difference between sides. Quite enjoying this discussion, the SX mechs always have intrigued me.
Here is the RQ-SX tape transport in all its "glory" I see nothing evidently wrong here, I have cleaned again the flywheels (still remnant of melted rubber), verified the motor and the discs do actually attract each other in any direction so I guess there is no special alignment. Do you see anything I should try or fix before putting it all together again ? I have run out of idea... Your reasoning on the reverse flywheel makes sense, but on the other hand it is driven directly from the motor with a short and tight belt. I was expecting its rotation to be more accurate; the forward flywheel is driven by two belts and even though it has a larger mass the pull force might not be very uniform. I suspect another type of failure, but I do not know which one. ----- please disregards any corrosion in the upper right corner, it was due to the old battery, but it impacted only the metal plate.
Two things I experienced on my SX-55 you can do just to rule them out: The red circle. Check to make sure that the motor's pins haven't 'sunk' from desoldering them. They are double soldered from the bottom, and they will sink sometimes when desoldered due to gravity. When you put the PCB back on, just make sure that the pins stick through the holes on the board nicely. They seem ok from the photo. The blue circle. That gear is one of two that connect the flywheel to the reel transport area. That gear is made out of two materials: a funny dark grey plastic, and a white plastic. For some reason, on both of my SX units, that gear became stiff and couldn't move just by rubbing it with my finger. Disconnect the short belt, and just try moving that gear by hand. If it's nice and smooth, you are fine. If it's stiff like mine was, the dark grey portion of the gear has slightly melted to the shaft, and will have to be removed and re hollowed with a tiny drill bit. Since that gear is incredibly brittle, never try to remove it with any force. This is all I can think of at the moment.
Thanks for your suggestions ! The pins on the motor are all fine: I know they are delicate (as the traces on the PCB) so i try to be very quick in soldering/desoldering, All gears runs perfectly smooth; no gear is stuck and i can rotate all by hand with very gentle touch. No obvious fault here
Welp, I think we have officially reached the end of my troubleshooting list then... I'll keep thinking though. It's very frustrating that these units exhibit no obvious problems, but act so bad. I would love to meet the engineer(s) who designed this mechanism and show him/her/them how they perform now. Maybe they would help me fix it! Anyways, if you do have any developments, feel free to post in this thread!
One desperate move would be to add a drop of watch oil in the flywheel bearings, but I really do not feel comfortable removing the washers that hold them in place. Otherwise blindly replace the pinch rollers, but I do not see them on sale and it might be a hell of a work for nothing. Anyway I think I will just reassemble the walkman and keep it as it is, there is really nothing more i can do with it. And I do not want to spend more money on it. I too find myself wondering if I could meet the designer/developer of a particular device and ask him/her how it should behave in normal conditions. Maybe they would help me find the problem in a moment. Sometime even the service manuals are wrong ! thanks !
I think i know what is wrong with mine: do you see those black bands on the capstans ? I thought it was rough surface, but it is indeed rubber ! OMG what were they thinking ?!?!? The rubber is surely no more perfectly aligned with the metal capstan and it is causing uneven tape stability. Incredibly dumb design, try to fix the problem of a poorly designed transport by making it even worse. Speechless.
