My DC Brick is fried! How can I fix it?

[marcoaam]

Hello everyone!

My DC Brick is also showing a problem. I opened it and the D8 diode seems to be exploded. Could anybody tell me what kind of diode is that?

Thanks in advance!

And sorry about my rusty English...

Marco  (Rio de Janeiro, Brazil)

[Kipper4]

Which DC brick is it.
Not that i can help you. I dont really do mains voltage stuff.
I'm sure it would help others help you though and

Welcome to the forum buddy.

[GibsonGM]

I have fixed many of them by simply using a VERY high-rated diode...something certain to far exceed the original specifications.   Warning - you may want to change them all - I'm not sure, but I think they need to be close to each other in terms of Vf and that sort of thing...

[marcoaam]

It's DCB-10.
Thanks, guys!

[teemuk]

Quite hard to help you without any service information but I can try....

- So the diode type is unknown... But are there comparable diodes elsewhere in the circuit? For example, the DC supplies might have their own regulator circuits and these are usually identical to each other, or at least identical to small group of each other (e.g. group of 7x 9V jacks and group of 2x 18V jacks in the brick). If the circuit section where the failed diode is one of these you can perhaps refer to working ones and find out the diode type. Alternatively the diode may be some other part of the circuit but some studying of the circuit should reveal if certain other diodes would be identical (e.g. rectifier bridge). Anyway, without any service information I have no idea where this D8 is in the circuit or what it is even doing and thus I really can't help you any further on that issue.

- Why did the diode explode? Obviously some fault somewhere caused this. The diode may be the component that shows obvious signs of failure but it likely isn't the sole part that failed. You need to prepare for the fact that the replacement diode may also "explode" and you actually need to perform more troubleshooting than simply replacing a single obviously blown component. For the same reason it is generally NOT good practice to substitute components like this with replacements that can handle more abuse; all the increased power handling just tends to reflect to other parts of the circuit. Now instead of a failing $0.01 diode you may have a failure of a $10 circuit section. This is not always the case but sometimes the ratings are deliberately low for "fusing" purposes.

Anyway, without any kind of service documentation I can not help more in your issue. I have no way of knowing what diode D8 is or what it even does in the circuit.

[GibsonGM]

^  Yup.  If you ever want to count on the power supply to be reliable, you are usually better off buying a new one.  Replacing the diodes and playing inside it is for desperation!    There are unknowns...a transformer winding could be shorted, things like that.   I should have mentioned that yesterday.

Could work for 2 hours after you fix it (taking up hours to repair), and then blow again.  Or it could go out badly, in that the device you have it connected to could be damaged!   Kind of a pain!  I'd rather pay the $70 for something good, or build my own power supply in which I know where the parts came from and how it all works...

[marcoaam]

Thanks, guys! I really appreciate any contribution.

It seems one oscillator has any problem. The d8 diode is there just to protect the power source...

I bought the unit from an American on Ebay. And he didn't tell me the DC Brick was fried. First time I got ripped... gotta count until 10 and let it go!

[jongwong]

replace the D8,original type is B340A,1N5822 can be korks will,good luck,man