Help Identifying Old Components - links fixed

[Milothicus]

I'm trying to draw up a schematic for an old tube amp i've got, and i'm not sure what these components are...

First are these green ones... resistors or capacitors?

http://inlinethumb13.webshots.com/2892/2021019200056514046S500x500Q85.jpg

Then these brown ones... same question

http://inlinethumb38.webshots.com/4005/2871303530056514046S500x500Q85.jpg

And i'm assuming this is a multicapacitor...

http://inlinethumb50.webshots.com/3505/2963701140056514046S500x500Q85.jpg


so does this contain two 20 megafarad - 500V capacitors? it just has two tabs coming out of the bottom, and the casing is soldered to the amp's chassis, so i'd assume that each tab, coupled with the casing is a 20 megafarad capacitor. does this sound right?

i'm looking forward to getting some parts of this amp working, but until i know what each component is, and i can drain all the caps, i don't want to poke around too much.

any input is helpful...

[vibroverbus]

your pic links don't work, but what your describing sounds right for a multi-cap can. but that'd be microfarads. a single farad is a huge measure, let alone a megafarad!

[Milothicus]

Moved photos. should work now...

[tonezoneonline]

The green caps are .01@600VDC and the black caps are .022@400VDC.
The dual cap is 20 X 20@500VDC.

[Milothicus]

so the green is .01 farads? or microfarads? what's the standard unit?

and when you say the multi is 20 x 20, does that mean that it just contains 2 completely separate 20 microfarad capacitors?

i guess their caps lock was stuck on when they were typing on the multicapacitor...

[vibroverbus]

so the green is .01 farads? or microfarads? what's the standard unit?


some kind of M = microfarads, and for larger cap types the std unit is microfarads (mf=uf=microfarads). for small value caps - ceramics & micas - sometimes they are labeled in picofarads. the unit (mf/pf) is often not inidicated either way, so it might just say ".002" and you have to 'know' whether that is mf/pf. there are also various systems that are used to encode the value, like "224" = .22uf. what, you think that's confusing!? I can't imagine why... :)

I had a great link for a few pages on cap identification lemme see if I can find it...

and when you say the multi is 20 x 20, does that mean that it just contains 2 completely separate 20 microfarad capacitors?

exactly, sharing the case ground as you said.

[vibroverbus]

Here it is... took a while to find, and that was even knowing it existed! Now I wonder how the heck I found it in the first place...

http://laspace.lsu.edu/aces/BalloonCourse/Electronics/References/capacitors.pdf

[Wakarusa]

and when you say the multi is 20 x 20, does that mean that it just contains 2 completely separate 20 microfarad capacitors?


The internal circuit on the multi looks like this (apologies for the ASCII art):


+ +
---| |-------------| |---
|
|
-

[Milothicus]

Great. thanks for the help.

according to the document vibroverbus posted, the standard unit is a picofarad, so I guess the M (mega) on all of these capacitors makes sense if we're talking picofarads. a bit ridiculous, but a megapicofarad is actually a microfarad. B+)

and thanks for clarifying the multicapacitor, too. i'll draw up a schematic of this amp and see what i'm working with...

[donnyjaguar]

Thanks for the link to the capacitor information. This is good print it and hang on wall of shop information. I do disagree with the statement that tantalums have long service life though. When I was designing equipment it was standard practice to use tantalums where you wanted the product to fail over time. The normal failure mode is short circuit so you could design in such a way that the failure would be catastrophic thus insuring additional revenues from service contracts. :) This sounds sinister but I assure you it happens often. Another piece of information missing from the document is that the black bar usually indicates the outermost element of the component. This is most apparent on electrolytics where the negative lead normally has a bar on it indicating this is the "can" part. Click HERE (http://www.columbia.k12.mo.us/jjhs/Technology/S&E0506/schermerp/images/capacitor.jpg) to see what I mean. This isn't unique to electrolytics (http://my.so-net.net.tw/tube/pic/CAP-s/ERO-03.jpg) though, but granted is of greater relevance in RF circuits. That said, I usually put the outer end closer to the lowest impedance side of the circuit even in audio.

DJ