Need advice in recapping old electronics

[Michael87]

Hey all,
I am planning to recap my old amplifier, tuner etc and when purchasing new capacitors to replace the old ones, do I need to care about anything else other than their voltage rating and capacitance?
Also, what kind of capacitors should I use?
Is it necessary to use the same type of capacitor as the old ones (e.g. replacing aluminium caps with aluminium ones, ceramic ones with ceramic)? I plan to use long-lasting capacitors.
Also, how do I know what kind of capacitor it is? In the service manual it just says CExxxx, CMxxxx, etc. What do those letters mean?
[LINK: https://www.manualslib.com/manual/940075/Luxman-L116a.html?page=7#manual]
It's my first time trying to recap any kind of electronic device so any additional important information is appreciated.

 

[c.coyle]

This is a big area to cover. There are lots of threads here on AK. None of your above questions have hard and fast answers. There are various general rules, but always exceptions.

If you are thinking about recapping a particular brand and model unit, search for it here and you may find one or more recap threads specific to that model.

It's not rocket surgery, but you're going to have to do a little reading.

 

[c.coyle]

Hey all,
I am planning to recap my old amplifier, tuner etc and when purchasing new capacitors to replace the old ones, do I need to care about anything else other than their voltage rating and capacitance?
Also, what kind of capacitors should I use?
Is it necessary to use the same type of capacitor as the old ones (e.g. replacing aluminium caps with aluminium ones, ceramic ones with ceramic)? I plan to use long-lasting capacitors.
Also, how do I know what kind of capacitor it is? In the service manual it just says CExxxx, CMxxxx, etc. What do those letters mean?
[LINK: https://www.manualslib.com/manual/940075/Luxman-L116a.html?page=7#manual]
It's my first time trying to recap any kind of electronic device so any additional important information is appreciated.

Look at the service manual screenshot you posted. As far as capacitor types, the right-most column under "Description" tells you the type of capacitor:

El = Electrolytic
Ce = Ceramic
Mi = Mica
My = Mylar
St = Styrene
Fi = Film

The only type you normally replace (again, there are always exceptions) are electrolytics. Electrolytics deteriorate with age, the other types usually do not to any significant degree. So, I would not change ceramics or any of the others unless you are sure they are faulty.

A few basic things that work for me:

When replacing electrolytics, you usually shoot for the same value capacitance, or as close as you can get on the high side, and a slightly higher voltage rating. For example, C710 in your schematic could be replaced with a 47uf, 10V electrolytic.

You'll also have to think about diameter (equivalent modern electros are usually smaller than old originals) and lead spacing, depending on how much space is available on the circuit board. Plenty of threads on this.

Stick to well-regarded, name brand electrolytics. Popular choices here are Panasonic, Nichicon, Nippon/United Chemicon, Kemet, CDE, Epcos, and Elna. Again, plenty of threads on this.

Buy them from reputable vendors, not from Ebay or the like. There are counterfeits. If you're in North America, Mouser and Digikey are reputable vendors, and very popular here.

Have fun learning.

 

[triode17]

I know this is old fashioned, but call Mouser Electronics and order a free catalog thru the mail. Its like 3000 pgs. and has essentially everything you need for any rebuild. Forget "lots of threads", this is much faster and you can choose parts on your own. I use Panasonic , Nichicon and Sprague caps. only for aluminum electrolytics. They are well priced and are reliable.

 

[c.coyle]

I know this is old fashioned, but call Mouser Electronics and order a free catalog thru the mail. Its like 3000 pgs. and has essentially everything you need for any rebuild. Forget "lots of threads", this is much faster and you can choose parts on your own. I use Panasonic , Nichicon and Sprague caps. only for aluminum electrolytics. They are well priced and are reliable.

Just wade through a 3,000 page catalog to learn the basics, huh? Nothing here on AK.

 

[triode17]

Just wade through a 3,000 page catalog to learn the basics, huh? Nothing here on AK.

No,no ,no. Good advice here, I give it as well but he asked about different caps. and what type to choose. Its all in the catalog. Why take the time to read so many threads if he can find it on a page, a real page no less. Your advice was good, don't be so defensive.

 

[Bob]

you should probably invest in a vom/dmm with capacitance measurement.

then develop a hard repeatable consistent for recapping. with each electrolytic cap
mark polarity on PCB. then for each and every cap AND ONE AT A TIME -
pull old cap, measure old cap, pick-up new cap, measure new cap, solder in.

if you don't mark the polarity and unsolder all the caps and willy-nilly solder them in
you may/will have problems. many threads here about reversed polarity caps,
correcting what may be a stenciling problem, soldering in wrong cap
(and the other cap is also wrong), and trying to figure out which of the
80 replaced cap is wrong.

and when done, document what you did here and send it along if you ever sell
or give away the recapped units.

and when you're finished

enjoy the music

 

[MrLem]

Here's some general rules of thumb for if you're not sure about anything:

Sometimes the type of cap (electrolytic, ceramic etc) can be changed but it depends on the circuit so unless you understand it inside out you're probably safer to stick with the same kind. As mentioned, it's probably only the electrolytics you need to be refreshed. Generally electrolytics are polarised (positive and negative terminals which have to go in the right way around) but some are not. Most other types are non-polarised. Keep an eye out for non-polarised electrolytics and make sure you replace with the same. If you're not sure about what make/model of cap to use and want a safe generalisation use Panasonic FC or FM for polarised and Nichicon for non-polarised (they do both types so be sure they're NP). For the big main smoothing caps use whatever fits the spec, but if you have to choose between options look at temp and life rating, plus ripple current. Voltage ratings can be treated as a minimum, in other words it's fine to use a higher voltage, just don't go lower. Higher voltages tend to be bigger so keep an eye on the physical size. Finally, if you can identify which electrolytics are doing signal coupling you might want to use Elna Silmic II for them, but Panasonic is fine if you don't want to get that specific.

Take lots of pictures at different distances and angles before you do anything. If you lose track they may well save your bacon.

 

[mroboto]

As MrLem said, you probably only need to replace electrolytics.

If you find low value electrolytics, like 1uf , 2.2uf , 3.3uf , 4.7uf or 10uf , you can be fine even better replacing those with film type capacitors (If they are used a in power supply applications (One lead to grounding circuit)), or as interstage coupling applications.

You can even use multilayer ceramic capacitors in power supply applications lower than 50V or as bypass (decoupling) existing electrolytics, but NO CERAMIC in interstage coupling applications, they are noisy, but be aware that ceramic caps don't always have their rated capacitance at rated voltage.

Take pictures and note the values of the capacitors you find using Windows Paint, don't rely on schematic for values, as sometimes the made changes in the production to adress issues or improve circuit, and that is not shown, updated, on the schematic.

If you change parts in a tuner, it will probably need an alignment after, because they are sensitive to changes.