Seriously, if I found capacitors that would fit and V rate would be lower but I would have no other choice I would change them anyway. They will work (we talk about small differences), only for shorter period.
".....I have no idea what voltages are for the capacitors inside of walkman's." RTFM. They're all listed.
Rule of thumb is the rating should (ideally) be twice the operating voltage or more. We also have space constraints in most cases. Will take the AIWA HS-PC202 as an example, but this is true for most slim walkmans where size of the capacitor is the biggest concern. While of course when restoring a walkman one should check the original rating and operating voltage, for the vast majority of scenarios 4V rating is good as most of these slimmer walkmans operate on 1.5V, 2V (some AIWAs) or 3V (2 x AA/AAA cells). Also most capacitors will work at lower voltages than the supply rail. Not to mention in practice designers don't always use caps with ratings of twice the voltage. See the example attached of TC-D5 series from SONY which use 220uF/10V caps on the main +/-9.4V rails. And guess what ? These units still work after 45 years with no hum/noise. While I do replace these 2 caps when I service these units with 25V rated ones since new 25V ones are same size as old 10V, I did measure some of them on the LCR meter and they're not that far off from new ones. There are many situations where the rating can be lower than original and still have enough margin left. As for working for a shorter period, in theory that's what is going to happen if they're operating very close to the rating. In practice I've seen many such cases (not talking just about walkmans here) where such caps have lasted for a very long time. For the most part, using common sense is important: don't use a 6.3V rated cap in a 6V circuit. However using a 2.5V rated one in a circuit that operates at 1.5V will be fine.
OP here. A few things. Firstly, I need to work on updating this list. A lot of these caps are reaching EOL or are already obsolete and no longer available. There is also one series of cap (UZS) I've forgotten to add. I have purchased and will be testing out some newer alternatives for the SMD caps (Wurth ASLI in particular). @dotneck335 I'm odgcwrtw on Tapeheads, you might remember me from a few days ago when I gave you some advice on setting record bias on a D6C. Allow me to explain this cap list and why the suggested through hole caps are 4v: 1. This is a list of the most commonly used capacitors for walkmans that actually or usually require recapping. In other words, this is for walkmans afflicted by capacitors that are known to fail. As it happens, most of these are of the slim late 80s to 90s variety, and virtually all of these run on low voltage. In fact, most of these are originally specified with 4v and 2v caps for the larger values (especially 220uf and 100uf). 2. In these machines, size is the biggest constraint, Especially height. This list is meant to help those casual users recapping these machines find suitable caps (which are slightly more difficult to find) with no effort. Caps of larger sizes and voltages are much more readily available and you should have no trouble finding them yourself whatsoever. For example, an enthusiast model that definitely needs recapping is the JX707 and its derivatives. Guess what? Nothing over 5mm will fit on that model without slightly or significantly bending the board due to space constraints. You only had 1 choice of SMD cap that would fit which is the Nichicon UZS series and that's gone now. (I was supposed to add the UZS to this list but that cap went EOL before I could be bothered to do so, Chemicon MVY was the other option, also EOL). 4. I'm assuming that the person reading this list is at least reasonably competent with electronics and would not use a lower voltage cap than what is specified or required. Very few walkmans that actually require recapping due to capacitor leakage or drying out require higher voltage caps. Off the top of my head, other than some very early chonky models, the DCC portables are the only ones that must need a recap and need some higher voltage caps. 5. I'm assuming you are offended by my list as you are interested on recapping your D6C based on what you've messaged to me about recently. The D6C is one of the few models that do use some 6v and higher caps. However, The D6C does not usually require recapping, especially the through hole version. Unlike other DD units the 1st gen D6C (which uses through hole caps) is not known to have capacitors drying out or leaking, unless you are in a high temperature and humidity country where the aging is accelerated. Capacitor failure on the later SMD revisions is relatively rare and I've only had to do that once on a 3rd gen unit, and that unit was from a high heat/humidity country. Even if you need/want to recap a D6C there is a lot of height/space available and there is no real need to create a list of capacitor models for it as there are so many options! You should have no problem sourcing caps that would fit from any major supplier. Again, since capacitor failure on the D6C is relatively rare, I'm assuming that if you have the knowledge on diagnosing that it is a degraded capacitor at fault, you would also be familiar with sourcing caps. 6. I do not recommend blindly recapping a machine unless that it uses capacitors with a high rate of failure, or have clear signs of failure (leakage). While there is no harm in doing so (unless one is inexperienced with soldering and you damage the board), it is generally a waste of time. So, how does one know when recapping is required if there are no clear signs of failure? Measure the capacitor's ESR, and capacitance. If the ESR is much higher than expected and the capacitance is very far off (20%), then it is worth recapping (and you might as well do the whole machine when it comes to portables).
Sorry I'm late to this as I'm more active on Tapeheads. Sadly the Nichicon UMW series is gone and the only through hole that is 5mm that is left is the Panasonic KS-A. You might want to consider Wurth WCAP-ASLI that I'll be testing soon. It is 5.5mm height SMD, but it is a low impedance type with higher than usual ripple current ability. In this sense, it's like a slightly taller version of the discontinued Chemicon MVY. Notably, its ripple current and impedance rating are better than MVY. With the base removed, legs bent down and used as through hole it should measure around 5-5.2mm. 220uf: 865080143009 The rest of the range is naturally also the right size for most walkmans. A tiny caveat: Wurth is fairly new to making electrolytic capacitors, they are made in Taiwan or China in what is supposedly their own facility. Long term reliability might not be as good as the big Japanese brands, but those are rarely made in Japan anymore (eg. The Panasonic caps mentioned above are apparently made in Malaysia).
@bub: I'm not at all offended by your list; the 4volt caps just seemed wrong to me. Then I realized that not ALL walkmans have a 6-volt rail like the WM-D6C does, and so 4 v caps would be fine in those units. Replacing ALL the polarized caps (84) in a WM-D6C would be a LOT of work and expense; it's just that I have had SO much trouble with aging tantalums in the past that I am quite leery of their performance. BUT....if it ain't broke, don't fix it, so I'll leave 'em be for now.
Maximum height of D6C capacitors depends on where each cap is positioned, as in some places there is space for ones taller than the original. For example when I replace C607 and C138 (on units that have been powered with reversed polarity), I install standard ones which are taller as there's more than enough space. Typically, the 4V rated ones are small (5mm height) and also the very low capacitance ones (<1uF) can be hard to find in small footprint.
For C607, I found this one: a Kemet ESS476M016AC2AA; 47uF 16V electrolytic, 105C 1K hr; 5 mm D x 7mm H x 2 mm LS @~ 92¢ each. C138 gets confusing to me---there are TWO C138s on the schematic---one off of IC101 pin 20, in parallel with C305 and D301. I suspect that this is really C318, a 220uF 4v cap. The "OTHER" C138 is the headphone output coupling cap, a 100uF 6.3v electrolytic that, IMO, should be larger and BiPolar if space allows. The SM schematic gets really confusing around the Dolby chip IC101 (201). Schematic shows pins 8 & 7 shorted together to ground and two un-notated caps on these pins to ground. Huh? PCB indicates that pin 8 is 0v and grounded. With no datasheet available for the CX20068, it's hard to tell what's going on here. For the smaller value caps, I found some PET caps (4.6 mm L x 3 mm W x 7 mm H) that should fit.
The C138 I'm reffering is the one going to pin 20 of Dolby IC, as I was reffering to just 1. The output coupling ones get replaced in pair if they are to be replaced. About being larger, keep in mind output impedance is also limited by R152 = 15Ω. There's an error there, pin 8 goes to ground (it's marked as ground in the block diagram), while pin 7 is a reference voltage that goes to the line above ground. Those 2 capacitors since there's no designator and no value, assume there aren't any capacitors there. See the DC2 service manual, that schematic is correct. I suggest since you want to do a full recap on your WM-D6C, make a list of all capacitors and share it here with dimensions and voltage ratings.
Yes, I see that the 15Ω resistor will influence the output impedance greatly. But, 100uF still has ~53Ω of reactance @ 30 Hz so it will still affect performance into 32Ω headphones. Thanks for the pointer on the schematic in Supplement 2--that one makes a LOT more sense! The 220uF cap is correctly labeled C318 as I suspected. Strange that they put that 22uF C305 in parallel with it---I guess they felt they really needed 242uF. I'm not sure I want to recap the entire WM-D6C or not. I guess I'll wait to see when my deck arrives (have a bid on one right now; cross my fingers!). I have had a LOT of trouble with tantalum capacitors in my career, so I have hard time trusting them.
So I have been watching WM-D6Cs for sale for a while now. Seller don't always post the serial #s, but I have noticed that the ones with WHITE (with black print) Dolby stickers are the earlier ones. It appears that the sticker color changed to black somewhere between Serial # 108671 and # 115865. Anyone have more info on this?
100uF gives a corner frequency f(-3dB) of ~50Hz with a 32Ω load, without considering R152 or amplifier's own output impedance (but this is low). If we consider the 15Ω series resistor, total load resistance becomes 47Ω giving a corner frequency of 34Hz. With a 16Ω headphones, the total load becomes 31Ω giving a cutoff frequency of 51Hz. The 220uF in parallel with 22uF is because they're designed to filter different frequencies. It's a common technique to put large and small capacitors in parallel on sensitive supply rails. As for a full recap, I maintain my opinion it's not necessary on the D6C especially in regard to the tantalum ones. Yes, I know tantalums were very problematic in some vintage equipment and gave a lot of trouble, but not aware of it being a problem here. What I would focus my attention on this unit is: - new rubber (capstan ring, idlers, belts, pinch roller) + re-lubrication and adjustments (motor position, flywheel thrust play); - condition of the head (some of them need lapping); - the 3 hybrid potted modules (would depot/replace them even if they work); - calibration: Dolby levels (these are off from the factory usually), bias and rec levels if it's intended to be used as a recorder. About the Dolby sticker, I noticed myself older units have a white one but never thought there's a correlation between generations and color of that sticker until now. Thanks for sharing the info !
Good to know that the tantalums on the WM-D6C are not problematic. But the other concern is that tantalums are also known to color the sound. I'd much rather have a film cap where they will fit. Do you lap your own heads or send them out? Do you know the serial # of when the transition from the "pointy" amorphous to the more rounded head occurred? I think it may be @ 80000, but I'm not sure. These later amorphous heads I believe are marked 35711 but then Supplement 2 also shows a part # 1-543-357-11. I thought that all those past Supplement 2 were permalloy heads.
I lap the heads myself. In regard to serial number, don't know it out of my head but there are a couple of threads about it. Think it was indeed around 80000, but don't quote me on that. The later amorphous heads (round ones) are indeed marked 35711, while the permalloy one is marked 35712. The pointy one has a sticker with SONY logo on it. Best thing to do is ask seller for a picture where top of the head is visible, if such picture is not already there.
See the table in the overview here: https://stereo2go.com/forums/threads/sony-dd-portables-genealogy.7410/ If any changes need to be made, please post in that thread.
Is there any chance to get THT Caps with 4mm diameter or lower ? For now i search for a 4V 220uF in a WM-F100II has diameter 4 mm and a lenght around 11 mm Thanks for your help
