Hi all

        I always thought I was pretty good at fixing walkmans or similar stuff. Mechanical issues - easy; belt replacement - straightforward (with varying levels of difficulty); general clean-up and adjustment - a doddle.  Diagnosing and replacing capacitors or similar components, however - er, no! That is a whole new ballgame to me. I assumed that when they failed, my shiny walkman was resigned to being a paperweight.

        Now I learn these can be replaced, returning a device to its former glory. By swapping out caps of different values, the sound can even be 'fine-tuned'. All clever stuff, but where to start? I reckon my Sony 'BF605 is suffering the dreaded bad caps syndrome. The radio works without fault (usually the case, right?) The tape side of things, though, sounds awful. There's a humming through the headphones, which sounds just like the noise the motor makes, and it gets worse with the bass on. What's going on?

Actually designated WM-AF/BF605. Classic late 80's/ early 90's Sony (think WM-150,190, EX49)

Mechanism works really well. I've desoldered the PCB from its ribbon cables, but belt can be changed without doing this, by flipping PCB up and over. There's plenty of ribbon cable to facilitate this operation.

Really small components mean if I have to change any , it could be a long night!

This is a cap, I know. It even has the polarity marked on to make replacement easier. But does it need changing? And how can you tell?

This has no polarity markings. Is the black stripe significant?

Maybe a capacitor.

Really small surface mounted capacitor.

So there you have it. Has anyone out there done a fix on this on this walkman or similar with same kind of issues? Love to get this one going again. Sound quality should be pretty awesome, especially with its EX amorphous head.

Cheers

Matt

AIWAs really suffer bad from capacitor failure. Check out the AIWA Capacitor tag for plenty of examples from AIWA

http://REPLACEMENT ERROR/tags/tag/224215475244401376

First step to cap replacement, get an ESR meter. High or off the scale readings = dead electrolytic capacitors. Not all dead capacitors leave a slick of acid all over the PCB.

Check out the 9th post on this thread for ESR meter manufacturers

index.php?board_oid=193392314111653483&content_oid=217178235650847317

The middle component is a 10uF 6.3V capacitor. Looks like it may be a tantalum. Unlikely to have failed, however they can rarely do so. The 3.3uF 50V cap looks like it might have failed there seems to be liquid seep from under the metal cap. The 4.7uF 35V cap to the left of the 10uF also looks to have liquid leakage under the black plastic plate.

This is a 47uF 4V electrolytic cap. The black stripe is the negative terminal. Note for tantalum capacitors the positive terminal is generally marked instead where there is minimal marking.

Yup another electro cap. 330uF 2V.

Most likely a 22uF 4V tantalum. The silver marking is the positive terminal.

That model is known for bad caps, like plop said get a good ESR, best one for smd, is  Smart Tweezers, or the Peak atlas meter the two I use the most, but will cost $300 and up, so only worth it, if you do alot of repairs. Otherwise get one of the cheaper meters, just make sure it does in-circuit testing.

The other way you can also do a quick test is to touch the tip of your solder iron to the one of the leads and you will smell a fishy smell, plus the pad will be more likely a dull color.  

It also could be a worn motor causing the problem, you can test by disconnecting the motor and see if you humming, or motor noise from the preamp, but doubt it. This walkman uses a very poorly design transport and is known for other issues as well with the clutch system. Tantalum caps do go bad. But do replaced all the electrolytic capacitors and neutralize the acids, as the longer they stay in, the more chances the traces are going to be eaten away.

Retro

$300 for an ESR meter? Even the more expensive Peak ESR70 only costs $142 including shipping to USA. Are import taxes that high?

http://www.peakelec.co.uk/acatalog/jz_esr70.html

Personally I think the Peak meters are over-priced for what they do. Pretty much all ESR meters will read in-circuit (circuit design pending). The only additional benefit the Peak meters offer is the in-situ capacitance reading, but even buying the cheapest ESR meter and a separate dedicated capacitance meter they are both cheaper than buying the Peak meter.

I bought the EVB meter kit for 52 Euros including postage, and it was a snap to put together. Even fully assembled and calibrated it is still only 62 Euros to USA.

http://clientes.netvisao.pt/greenpal/evb1.htm

I got the 3 kit one, yes do think they are still way overpriced, paid $260 came with a LCR a DCA and ESR plus meter, is a pretty good kit. But you can built a just ESR for $60 bucks as a kit, otherwise they cost $119 and up for a decent one, the Smart Tweezers is also a LCR and ESR meter, good for SMD's but cost over $300. I won't even talk about B&K meter they go to the $500 and plus and can't understand why? How much profit margin does a company need? 

Thanks for the link, going to recommend that for a friend that was asking about one. 

Tants may affect sound quality.

I suggest looking for the United Chemicon MVY/MVA series, the MVY series has low height that should fit.