[Jukebox-list] capacitor values

[rockolakid]

Thank you very much Jay.
    Best Regards Doug.
----- Original Message ----- 
From: "Jay Hennigan" <jay at west.net>
To: "Jukebox mailing list" <jukebox-list at lists.netlojix.com>
Sent: Thursday, September 27, 2007 9:25 PM
Subject: Re: [Jukebox-list] capacitor values


> rockolakid wrote:
>> Hi All,
>>           I have had problems with my Rockola 1448 I have located the 
>> fault to a faulty capacitor in the control box assembly, there are 4 
>> inside all the same size I want to change them all, the drawing says they 
>> are 0.5 MFD, but I am confused by the colour band markings they are 
>> yellow/purple/orange/grey/    yellow, the control voltage is 28v dc, can 
>> any one on the list explain the markings, does the value add up to 0.5 
>> MFD.
>
> This is the standard color code, similar to resistors.
>
> 0 black
> 1 brown
> 2 red
> 3 orange
> 4 yellow
> 5 green
> 6 blue
> 7 violet
> 8 grey
> 9 white
>
> Crude but effective mnemonic:
>
> "Bad boys rape our young girls but Violet gives willingly"
>
> So, the first three bands of 4-7-3 correlate as follows, in picofarads:
>
> 4, 7, followed by 3 zeros = 47000 picofarads, equivalent to .047 
> microfarads or .05 should be close enough.
>
> The fourth grey band is probably actually white, indicating a tolerance of 
> +/- 10%.
>
> The final yellow band is the voltage rating, 400 volts.
>
> A .047 or .05 microfarad, 400 volt or higher capacitor will replace it 
> just fine.
>
> The capacitor is almost certainly bad.  These use a spiral of paper and 
> foil, and moisture over the years causes a partial short.  I would change 
> out all of the "bumblebee" capacitors, especially in the amplifier.  Don't 
> throw them away, however.  Keep the leads as long as possible and sell 
> them on EBay to the guitar people who pay big bucks for them.  These were 
> original equipment in vintage electric guitars and they want them 
> authentic.  At the millivolt levels seen in guitars, the leakage isn't 
> dangerous.  The sound may be distorted, but distortion seems to be a good 
> thing in the case of some electric guitar players.
>
> See also:  http://www.wjoe.com/capacitorinfo2.htm
>
> --
> Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
> Impulse Internet Service  -  http://www.impulse.net/
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