Is this right? Picture attached, but I'm scratching my head. Some readings are at 47 muf, some at 4.7 muf... er... at the moment I have little confidence in my reading the caps correctly to be sure I've got the right numbers before I move forward and attempt to do some ordering. I've been watching videos of people recapping this unit and they don't seem to have that many different caps by their side when they do it. Can someone boost my confidence in my reading here, or else point out what I've done wrong so I can re-do it please?
Have you got a service manual ? A quick Google suggested one is available on Stereo2Go. With a service manual I would simply print out the relevant sheet and check the capacitors as you remove them in case it there are differences (unlikely but possible). Don't forget that electrolytics are polarised so have to be fitted the right way. Older through hole capacitors tend to be more reliable but I suspect my 1976 Amerex cassette recorder needs some replacing.
Yes, I do have the service manual... however the capacitor listings only list a partial value. They are listed instead by part number and although I do sometimes get hits, I get geoblocked. UED.Net for example, geoblocks. I can use a cache page to get at the list, but if I click on any of the links, I'm dead in the water. I can use Web Archive to get at those pages, but usually they are then to part numbers and usually they are also out of stock and don't actually detail the value of the capacitors anyway... like this - https://web.archive.org/web/2021020...ued/viewItemAction.do?itemCode=MSCECAG25E0R47 - yes, it does nark me that some places like UED seem to have shopping lists of all the caps I need for a unit, and I can't buy the things from them. So I'm stuck with having to do a manual search of the board and work it out.
For a bbox I did full recap only once - for RC-550 "El Diablo". Having SM gives extra confidence that even in the worst case you won't have to buy another one to check cap values. I do not remember actually notating each cap on the board, but just made a list of all the caps used (marking them in Red as I counted) and then recapping only same value caps at a time. And double-checking their values as I pulled them out!... The only "danger" to look for is to check if polarity is marked on the board. If not (axial C43 @ the second photo) then photographs of the board before recap helps; if no photo then you have to pull out SM. Good luck, I still remember the "sense of accomplishment" once I finished that El Diablo
That's quite a job! Who'se caps would you recommend I try and buy for through hole? Also, there's an amp with a heatsink and I'm going to have to take the heatsink off... so when I do, what paste should I use to replace with? Will the stuff I use for computer processors work, or do I need something with a different composition?
I just looked at the service manual and to me the schematic shows more information than the layout or parts list. For example C139 is labelled 10V1000 which I guess is 10V 1000uF which sounds right for a speaker coupling capacitor. The parts list says "all capacitor values in uF" P is Picofarad. They seem to have not used the intermediate nanofarad (which is the same as 1000pF or 0.001uF) Regarding the layout, assuming you have a printer I would have just printed it it, maybe using the multiple sheets (print as poster) facility in Acrobat. On some shortwave radios I have been up to a dozen sellotaped together sheets to make everything clear and enable me to see the bigger picture. As for the make of capacitors Panasonic is still a big manufacturer. Any components labelled M or three triangles on a triangle (similar but different to Mitsubishi) are Matsushita which was Panasonics parent company until they decided Panasonic sounded better https://www.google.com/search?q=mat...XJPsAKHeNkCdkQ_AUoAXoECAcQAw&biw=1680&bih=850 Finally as for thermal grease, they would have been using standard silicon grease, the same stuff that comes with cheap motherboards. I would avoid any fancy silver loaded stuff just in case it causes a short. Look out for, and don't lose, any insulating washer which may or may not be under the IC. Good luck.
I am replacing what I think is a like for like cap... but the replacement is small enough for me to consider whether the (M) by the side of the 1 muf symbol means I've actually got the wrong replacement cap? Or is the replacement just a better/smaller cap and the value is correct?
Capacitors have shrunk quite a bit over the last forty or so years. Otherwise Walkmans would have stayed the same size as a TPS-L2 and mobile phones would still be the size of a brick. Of course we won't know if the new ones last as well until forty years time. p.s At least the ones you are dealing with aren't surface mount. As any Aiwa personal stereo or Sega Gamegear owner knows the first attempts at making small surface mount capacitors were a disaster.
Thanks for this. I think what's confusing me even more is that the new 0.1 muf 50v cap (not pictured) is a little more than twice the size of the 1 muf 50v cap. These sorts of things are making me scratch my head... but common sense says that physical size is only loosely related to capacitance.
It is actually unusual for anyone to use electrolytics less than a couple of uF these days, so they probably didn't bother making a minature version. Last week I was going to suggest that you swapped the low vale ones for something like Polyester but then read a thread on a HiFi forum in which people were saying that isn't always a good idea especially if you are familiar with the circuit. They also might not fit easily. High value ceramics aren't a good idea as their capacitance changes with the applied voltage.
After my experience shopping for some of these caps, I do worry whether in a decade or two, it will be impossible to get some of these caps and render some repair work not possible. I do expect these re-caps to last my life time, however. Plus the UK will likely switch off FM radio in a few years. They've had two goes at it already (at least) and they keep trying. It's only a matter of time. I've also only just noticed that my version of the RX-C45 doesn't have any noise reduction on it. Hmmm....
