So I have my BNIB F701C. A beautiful Sony radio equipped model with Dolby-C even. When trying to play something (tried AA only, gumstick is on the way). It basically "tries" to do something but almost immediately shuts off. Absolutely no movement is made by the rotors. So my first assumption was to buy a new belt, which arrived today (thanks Marian!). I was about to open it today and have a proper look at it over this weekend. Following this video, the first thing I immediately notice is the guy takes out a CR2016 battery from the top right inside corner. What is this battery for? I can't find a service manual for the F701C specifically, but I can find one for the 701C. Which does not seem to have the battery. I assume then, the battery is for the LCD or the Radio. However, both function fine without it and just with the AA. Which again begs the question, what is this little CR2016 battery for? EDIT: <A bit later> Whilst looking harder I find Sony.com still has the original user manual and the battery has only one simple job, to let the machine remember your saved radio stations. Seems like it could have been something to leave out of the device to be honest, but hey I wasn't even alive back when they made this thing. So I can't talk like this was/wasn't an important feature. ----------------------------------------- Which brings me to my main question. I am presuming that the belt on this thing is going to look exactly like the guy's in this video at 03:00. But does anyone know of any other problem this particular model can face, or anything else I should know regarding fixing it? What should I expect of the capacitors seeing as this device has never been used and has stayed inside its original box its entire life. In the meantime, I'll get about taking this thing apart very carefully and documenting my findings.
The belt, in the vast majority of cases will look like in the video. Chances are there's also a green residue on the brass pulleys which will need to be cleaned well before installing the new belt. In regard to capacitors, these models use only tantalum and ceramic capacitors, so really nothing to worry about. Then, 2 things I would check are: - if the table reels turn freely (there are some small gears that usually get stuck due to old grease); - if the middle black plastic pulley turns freely; Buttons can have problems with oxidation on some units, but not really that common. After you get the unit to work, just check that every button does what it should and functions are not swapped between buttons, which would be a sign of increased resistance. Volume potentiometer and switches (Dolby, EQ, MegaBass, autoreverse) may need cleaning. If the volume potentiometer has the typical crackling, just clean all of them. Recommend Kontakt 60 for that. Pinch rollers, given the unit has never been used, would expect to be fine and leave the original ones if that's the case.
The coin cell should only be for radio station presets and/or clock - at least it is in my FX70. The unit works without, be it without presets. Aiwa did use a little rechargeable coin cell in the JX70 series, so you can actually swap the main battery (or switch between sidecar and gumstick) without memory loss.
So I finally got around to fixing this one after spending the long weekend with family. It was a piece of cake. Took the top off and sure enough the belt had snapped. The bottom flywheel had 'absorbed' a bit of the rubber and gotten stuck, so I assume that's where it failed. Took my sweet time cleaning out all of the rubber 'goo' without damaging the tiny plastic flywheel. You can see it's sort of "stained" the flywheel. I did my best to get it all out with the tools I have but it'll probably never look completely clean again. Was hesitant to use any kind of strong alcohol etc. in case the residue gets stuck on the flywheel and ends up just speeding the decay of the new one.
I'm pretty satisfied with Marian's belt. Not sure if this is a good or bad result for the belt I got from him. I made extra sure that the belt wasn't twisted anywhere when carefully installing it. The W&F seems a bit high (bit over double my DD models) but this could be due to a few different things. I bought the device BNIB and it has never been used. Capstans are spotless, pinch rollers look immaculate and the overall condition of the device looks straight out of the factory. I also carefully checked the grease for the gears and the mechanism and it seems to be working as new. If there's something not working properly, its outside of my knowledge. Volume pot got a tiny drop of audio cleaner to roll it in as it had the tiniest bit of scratching. That said, the speed of this thing is about as perfect as it gets for a non-DD model. The seller of my tape told me I should consider 3002Hz as the mid point as his Nakamitchi ZX-7 had drifted slightly. Which would put this device only ~4.5Hz off 3000Hz. If anyone has any ideas of how I could drastically lower the W&F, I'd appreciate it. Though I'm not expecting any miracles for this model. That said, it not only looks but sounds absolutely incredible. The quality of the Dolby-C circuit is just amazing. DBB is such a huge step above the DD model's "Mega Bass". The mid option is actually really nice and punchy, but the Max position is way too high. Noise cancellation is fantastic and overall I am extremely happy with the device. Apart from the kinda high W&F, its an otherwise flawless device. I just wish I had a proper leather case for it. Might need to get one made.
The W&F result is good in my opinion, especially considering there was nothing done apart from swapping the belt. In regard to the belt's impact on w&f, what we have to acknowledge is most belts available nowadays have higher manufacturing tolerances than the original ones. So for a perfect result, it's not so much about the supplier of the belt (not that it doesn't matter), but rather about buying a batch and choosing the best one. Mixing belts from more suppliers will increase the chance of finding the best one, but in my opinion it's not worth the effort since this is not a deck with spec of 0.02% WRMS. What I would be curious is if the W&F figure improves after using the walkman for a while (10 cassettes played). And possibly clean the pulleys a bit more, on last picture of post #4 it looks like there is some leftover residue on the white idler pulley. IPA can be used safely on these pulleys. Agree with Dolby C working great on this model. The fact it's NOS helps in this regard as tape path alignment is as close to perfect as it will get. DBB middle position I find pretty good. But if I am to find a flaw of these series (apart from w&f), it will be bass response which just isn't great (reffering to the response without DBB).
Hey Valentin. Thanks a lot for the information. Yes there's a tiny bit of residue left on the white pulley. I did everything I could to get the rubber off but I'll give it a go with IPA as well. At least at this point it seems like the leftover rubber from the old belt was more of a "stain" than anything I could see actually impacting the the transfer of the belt. Belt looks to flow really smoothly and the mechanism and gear looks really healthy. Direction change, start, stop, FF, RW etc. all work extremely well and the buttons feel extremely solid and responsive. I can't notice the W&F difference between this and eg. my other belt devices despite them being more in the 0.2% RMS range. Most importantly (to me) the circuit just sounds extremely good and the device is very loud whilst remaining extremely distortion free. There is no motor hum whatsoever, no background noise and I actually can't hear any even faint part of the other side of the tape during playback. It seems to be in really, really good condition. My serial number for this device is also really low, which I've heard can be either good, bad or mean nothing. I've only tested 2 tapes at the moment because it was really late, but the DBB definitely surpasses the DD Mega Bass, at least on the models I have. In any case, it really feels like a hifi Walkman and I'll definitely be keeping this one.
For most music genres out there, indeed you won't notice the difference between 0.2% and 0.3% WRMS, the value at which it becomes really noticeable is a bit higher than this. Exception to this is classical music or any music with long note decays, that's where the w&f will become very audible and even 0.2% will seem very high. Indeed sound quality is good on this unit and the headphone amplifier can give a pretty clean output up to a volume 8. Power-wise it's good enough in my opinion, but will struggle to drive higher impedance/less sensitive headphones loud. It's only rated 2 x 5mW after all. The big advantage is it operates on only 1 battery. Don't know much about the serial numbers on these series, but don't think it means anything important for the 700 series. If anyone knows more, let us know. As for low serial number being a bad thing, not aware of a walkman where that would be the case. Curious to find out more about this.
I don't understand the comment about the serial number, any link or reference to the high/low good or bad statement you are referring to would be nice. In service manuals of the 700 series units, I did not find evidence of significant redesigns or different components.
