Dual 721 Rifa X2 safety capacitor

[kwatch]

My Dual 721 pops during powering on and off. It's been like this for a while. I need to replace the Rifa X2 safety cap. Can some one direct me to the direct part link at Mouser or Digikey Electronic? Thanks.

 

[bangsezmax]

This is the one I've been using when the originals go bad: http://www.mouser.com/ProductDetail...zHHKlrkNaRzeI2NL%2bhOP20qDhCdXtvPrSZPNQ5Zxw==

Mouser say's the product is end-of-life FWIW.

 

[gusten]

http://www.mouser.se/ProductDetail/...1cc3ydrPrF9qGa6BI3F0oO7aoeuyPlIvxX4HlXtVSKw==
The one You have.

 

[kwatch]

Which one is the safety capacitor?

 

[gusten]

Maybe it doesn´t look like one. What does it say.

 

[Wirehead]

Use any X2 rated cap of the same capacitance with equal or higher voltage rating. Those Rifa's go bad in about any appliance you can think of. (Yamaha amps for example have the same issue..)

 

[kwatch]

Should I replace the white cap or the green cap?

 

[gusten]

Should I replace the white cap or the green cap?

It seems to me the green one is an X2 cap, can´t see what the white one is.

 

[bohhey]

The Rifa cap is notorious for splitting in half and causing a dead short, blowing the fuse. They were used where the green one now is. Dual went to the green one after so much trouble with the Rifa cap. It can't hurt to put in a new one as we all know caps deteriorate with age, but these green ones seem to hold up better. The replacement I use is a .047 mF x 400 V. film cap.

 

[bohhey]

Oh wow - I need to pay more attention when I read. The on/off pop has nothing to do with the transformer. In the power distribution box (where the power leads go - it is labeled KS-4) there is a .068 uF x 250 V cap across the hot lead to the table. This allows a very small amount pf current to pass through even when the table is off. Then, when turned on, the spurious "pop" is eliminated. I use a .10 uF x 400 V film cap here. A simple solder job to replace. Obviously, disconnect the table from the power source first!

 

[kwatch]

I have http://www.digikey.com/product-search/en?keywords=399-7481-ND . Is this a direct replacement for the green cap?

 

[gusten]

I have http://www.digikey.com/product-search/en?keywords=399-7481-ND . Is this a direct replacement for the green cap?

Yes it is.

 

[kwatch]

I'm confused. C52 is the safety cap and C51 is the cap preventing on/off pops. Am I correct?

Diagram from 721 service manual.

 

[bohhey]

Did you not read what I posted earlier on this thread? The POP has nothing to do with the transformer!

 

[txc500]

Hi everyone, I just got a Dual 721, it has the same issue everyone is describing, blowing fuses. I am seeing a lot of photos of the circuit board from the top, mounted. Does anyone know of any photos or video showing how to remove that circuit board and what it looks like from the underside?
Thanks

 

[txc500]

Oh wow - I need to pay more attention when I read. The on/off pop has nothing to do with the transformer. In the power distribution box (where the power leads go - it is labeled KS-4) there is a .068 uF x 250 V cap across the hot lead to the table. This allows a very small amount pf current to pass through even when the table is off. Then, when turned on, the spurious "pop" is eliminated. I use a .10 uF x 400 V film cap here. A simple solder job to replace. Obviously, disconnect the table from the power source first!

I wonder if you can help me here, I had the rifa (it was actually the green capacitor) replaced but now it runs until it switches off, then the fuse blows. Would that likely be the cap in the power distribution box?
Thank you!

Oh wow - I need to pay more attention when I read. The on/off pop has nothing to do with the transformer. In the power distribution box (where the power leads go - it is labeled KS-4) there is a .068 uF x 250 V cap across the hot lead to the table. This allows a very small amount pf current to pass through even when the table is off. Then, when turned on, the spurious "pop" is eliminated. I use a .10 uF x 400 V film cap here. A simple solder job to replace. Obviously, disconnect the table from the power source first!