What kind of Capacitor

Thread Starter

shirreff

Joined Sep 6, 2011
36
Hi all,
This is my first post,
I have 2 power supplies, one good one bad they are 240 volt and have 2 outputs each, one is 5v and the other 12v.
A keyboard I was fixing had an error message on the screen which I worked out as being a power supply issue. I swapped the good supply for bad and hey presto the keyboard was fine but I wanted to fix the power supply.

I slowly began swapping various components until I found the culprit.
It was a capacitor (I think). On the circuit board it says C18 next to it so I assume that means it is a capacitor.

I want to order a new one but I don't know what to order.
As far as I can tell it is very small about 4mm black with 2 silver stripes and 2 8 and I think E or could be E written on it.
I have a diagram and it has 220 over 25 next to it if that helps.

A good link to a page that lists different capacitors/resistors and how to identify them would be great also.
thanks in advance.
 

JingleJoe

Joined Jul 23, 2011
186
A quick google search could probably find you other examples of your cap.
As for the value, thats almost certainly 25 volts and 220 (something)farads [farads are a unit of capacitance but most commonly we use microfarads because one farad is acctually HUGE capacitance] so your cap could be 220 micro farads or nano farads or pico farads ... we need a pic to identify it really, but like I said, google can help you better than we can at the moment.
 

Thread Starter

shirreff

Joined Sep 6, 2011
36
Capacitor-I-dont-know.jpg

Hopefully I have uploaded the image correctly!
I have tried searching on google but I don't know enough about components to choose the correct one. I am relying on finding one that looks the same.

diagram.jpg

I have uploaded the circuit board diagram, frustratingly I have the parts list for this keyboard but this board is not included on it.

It is a late 1980's board from a korg M1.
 

Thread Starter

shirreff

Joined Sep 6, 2011
36
you will know better than me, I am assuming it is a capacitor because it is labelled C18 on the board. I am by no stretch of the imagination correct.
 

JingleJoe

Joined Jul 23, 2011
186
Almost certain that's a diode (Also woo! Synthesizers! I'm getting one of mine repaired at the moment) I have a feeling you may be looking at D6, the labeling for the capacitor may be misleadingly close.
 

bertus

Joined Apr 5, 2008
20,754
Hello,

In the photo you show a diode.
In the schematic you are pointing at a capacitor of 220 μF / 25 Volts.

Bertus
 

JingleJoe

Joined Jul 23, 2011
186
Wasn't there a part number above the diode in the circuit diagram? Stick it in alldatasheet.com or google or something, perhaps you could find the exact same kind? Or an equivalent?
 

R!f@@

Joined Apr 2, 2009
9,734
If it was me fixing it, I would replace with exact diode no. and together with C21,C23,C18 and C19.

The caps are all 220uf/25V. Use low ESR types.

Is the diode no. starting with CRB or ERB
 

Thread Starter

shirreff

Joined Sep 6, 2011
36
Ok it says DF 28 E and the data sheet says crb4402,
I must be getting close.
I can see lots on Ebay for schottky diode but I don't know what amp and voltage to get. I have tried searching the above part numbers with no joy.
 
Last edited:

R!f@@

Joined Apr 2, 2009
9,734
Then get me a good pic of the diode on the PCB

Scrap that.

Find any 1Amp Schottky diode or better yet, have u got any junk PCB's or Computer power supplies ?
 
Last edited:

Thread Starter

shirreff

Joined Sep 6, 2011
36
Capacitor-I-dont-know.jpg

DSCF4648.jpg

diagram.jpg

that's the best I have got.
I have a few pcbs but I am trying to fix them and re-use. I have pulled parts off one which is in the the picture but the rest I want to repair.
I will gladly buy new diodes 1amp yes any voltage? would a higher amp be better?
Ps the last pic has the wrong part circled.
 

R!f@@

Joined Apr 2, 2009
9,734
Any black coated diode used in switched mode supplies will be fine for ur replacement.
Just find one of the same size.
 
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