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So I have a Marshall Silver Jub on the beach right now and while it's fixed and it's nothing wrong with it anymore I have a small problem

It's quite different to other Silver Jub schematic I saw so I decided to trace it and document the differences

The thing that gives me a hard time is those fucking ceramic axial caps with a colour bands (5 bands)

Are they having different way to determine the value to let say bubble bee's or tropical fish caps?

sinner wrote:So I have a Marshall Silver Jub on the beach right now and while it's fixed and it's nothing wrong with it anymore I have a small problem

It's quite different to other Silver Jub schematic I saw so I decided to trace it and document the differences

The thing that gives me a hard time is those fucking ceramic axial caps with a colour bands (5 bands)

Are they having different way to determine the value to let say bubble bee's or tropical fish caps?

The colour coding probably works the same way as the coding on those Tropical Fish caps, have you tried googling for info on those ceramic caps?, another thing you could try is buy a Digital Multimeter that has a Capacitance measuring function on it and use it to measure the capacitance of one of those ceramic caps after carefully de-soldering it, you could then write down the reading and compare it with the colour bands, hope that helps......


If anything, at least one of the colour bands will indicate the tolerance +/-% of the marked value that the capacitor was manufactured to, another band will probably indicate the working voltage, and the remaining bands will probably indicate the Capacitance value, but I reckon you could just measure the Capacitors.....


I just did a quick google and came up with this:

https://www.google.com.au/search?q=Colo ... w#imgdii=_


And this:

http://www.tpub.com/neets/book2/3g.htm

Well. The thing is i have googled two ways to calculate the bands which none is relevant to those caps

I cannot really desolder anything on customer's amp, bro

(I agree those can be confusing to read. My (non-expert) tips: )

-think about the circuit location and a likely value

-you could be reading from the wrong direction (i.e. you might be starting with the tolerance band)

pictures might help?

Colour coding seems to be quite well established and standardised across the world, so I think it would be reasonably safe to assume that you can read the values correctly as long as (as pointed out in the previous reply) you start at the correct end.

One possible difficulty is in the precise identification of a colour - some browns and oranges can appear to be red (etc) - so clean off the dust, get a big bright light and your granddad’s jam-jar-bottom specs and dive right in.

And if it’s possible to post a picture, we could ALL join in the fun.

Good luck, buddy.

Let us know how you get on.

Thanks guys

I will upload the photos somewhere next week. I'm waiting for some virgins to fix my broadband

Looking forward to checking out the pics.....

Here's one on my Facefuck page



I'm sorry for the quality, I was using toaster to take this shot

It's quite surprising little shit to be honest. It's circa 1988 2554 1x12 Black Jubilee combo. No choke, 3rd generation (if I can call it that way) preamp board. Slightly different layout to the one I've redone months ago (some extra resistors, at least two capacitors in different value, the other one was silver jub 100w on... 4th gen board!!!)... what else... oh yeah, SMD's schematic have an error in PI (construction error, not value)

This thing should be documented soon and put on my oncoming website (1st of May)

I need some input from guys who owns Silver Jubilee, Black Jubilee or 90's Slash signature model. I really want to make the story of this amp line straight

So... If u have Silver/Black jub or Slash sig and u fancy to help - get in touch, please

sinner wrote:I'm waiting for some virgins to fix my broadband

Did you try sacrificing your first born at full moon? It might free you of your broadband issues

I tried everything

Really - it's easier to get laid than score decent broadband in my neighbourhood

In that case:

Find yourself a BROAD.

Get Laid.

Get BANneD.

BROADBAND !

Seemples !

Where I live, some workers recently installed some infrastructure for Australia's new NBN (National Broadband Network) Optical Fibre Internet, I talked to someone who said I could get myself connected on a Telstra plan which would give me 8Gb download for $99.00 per month, been doing some serious thinking about it, I'm currently on a 4g Wireless prepaid and I usually buy $100.00 worth of credit which only gives me 6Gb download..

Fuck me... now I consider myself lucky

Hope this help

The picture examples from Tip142 are great - thanks for those, Tip142.

The top three bands are the value - same as for three-band resistors. Note, however, that for values such as 22nF, the top two bands will just appear as a thicker red band. This can get confusing, as the bands are not separated like on resistors - that’s because the caps are held by the legs and dipped into successive colours, starting with the fifth (ie, lowest as seen on the pictures from Tip142) and gradually working up the body.

The fourth band appears to be either black (20% tolerance) or white (10% tolerance). There may be other tolerance band colours (as there are on resistors).

The fifth band is the maximum working voltage: Red = 250v; Yellow = 400v. there may be other ‘voltage’ colours, but I am not aware of them.

Quite often you can see what appears to be a light brown band below these five bands, where the legs meet the body - but that is just the body colour of the cap.

I believe these ‘tropical fish’ caps have been described in a previous topic, and that someone was able to quote from the manufacturer's spec sheet.

sinner wrote:It's quite surprising little shit to be honest. It's circa 1988 2554 1x12 Black Jubilee combo. No choke, 3rd generation (if I can call it that way) preamp board.

http://forum.ampage.org/forum.php?cmd=vt&tid=36707
http://forum.allaboutcircuits.com/threa ... elp.43489/
http://www.marshallforum.com/workbench/ ... itors.html

Do you mean these?

(looking at the picture above) it looks like Marshall actually bothered to insert the Rs and Cs in the same orientation (i.e. tolerance bands facing same way) so that should help a bit.

(Again, I think it would be best to try to follow the circuit--at least for the areas(caps) in question plus compare to a schematic, but) "C11" = YEL-PUR-RED?-BLK-GRY = 472-something-something = 4700pF (or, is RED actually ORG, which would make it 473 = 47nF--this is why these can be confusing to read!). (I'm ignoring some of the extra bands (SIL = 10% probably, GRY = seem to be on the larger value ones so very loose tolerance types (-20 to +80% or whatever)?) indicating tolerance and whatever) "C10" = YEL-PUR-BRN = 471 = 470pF? "C9" = BRN-BLK-ORG = 103 = 10nF? "C7" = ORG-ORG-BRN = 331 = 330pF? And so on.

Some codes here that includes similar caps and chokes, like the picture previously posted

I think that chart makes more sense for the real old tubular ceramics (sometimes referred to as "rod" or "dogbone" types), but not so sure for the (relatively newer--around 90s) ones in the picture.

This chart here:

http://www.electronics-tutorials.ws/cap ... cap_5.html

makes a bit more sense (example, GRY = +80%, -20% which makes sense for the cheap ones in 10s of nFs), but not sure what the BLK band previous to the last GRY band indicates.

(must be a datasheet somewhere!)

Ok. I think I got it - cap across input gain pot

Brown / black / red / silver / silver. On marshall schematic that should be 1nF (1000pF)

Another one. Cap across rhythm diode network - should be 2n2. Bands are red / red / red / black / grey

First three bands value, last two voltage/tolerance

basically how to get the value is clear, the tolerance and voltage is not