Recapping Falcon PSU - My rectifier is different

[derkom]

I'm in the process of recapping a Falcon PSU with exxos' kit (hoping to tame a ~300 mV ripple on the +12V rail) and after replacing all the caps, I've noticed that my rectifier doesn't look anything like the one in the photo on exxos' PSU page, and also there's a resistor missing from right next to it (R4). (I imagine it's simply not supposed to be there, and this is just a slightly different revision of the PSU. I am also missing R18 in the upper right.)

IMG_20180919_122549.jpg

I am reasonably comfortable with electronics, but not nearly the level of a lot of you guys, so I figured I'd better ask here before continuing. Does anyone recognise this revision of the Falcon PSU, and am I good to continue here and replace the rectifier with the new one from exxos' kit?

Thanks!

[kodak80]

The bridge rectifier is the original square one and is correct. The one Exxos supplies is slightly different but has 4 legs so you need to make sure you align the positive and negative legs:



R4 and R18 was missing from my Falcon PSU and they look the same. Recap worked fine.

[derkom]

The bridge rectifier is the original square one and is correct. The one Exxos supplies is slightly different but has 4 legs so you need to make sure you align the positive and negative legs:

R4 and R18 was missing from my Falcon PSU and they look the same. Recap worked fine.

Yep, no worries on the legs. Thanks for filling me on the other details. I shall continue the project. :)

[derkom]

Oh silly me. If I'd just looked at the beginning of the Falcon section on the PSU page, I would have seen a picture that matches mine. Good job, me. :oops:

[exxos]

The differences on the resistor are 110V vs 240V configs.. some better images in this section.

https://www.exxosforum.co.uk/forum/viewforum.php?f=59

[derkom]

...and it's done.

+12V ripple before...

MZK8UfN.jpg

...and after...

IMG_20180919_145713.jpg

50 mV/div in both cases.

:dualthumbup:

[exxos]

:bravo: :goodpost:

[Atarian Computing]

...and it's done.

50 mV/div in both cases.

:dualthumbup:

Cool, so from 250mVpp to 100mVpp? What kind of load are you running here?

[derkom]

Cool, so from 250mVpp to 100mVpp? What kind of load are you running here?

Both times just using the load resistors supplied by exxos. :) "5V uses 2.2R (loads 5V rail with 2.2amps) and 12V uses 10R (loads 12V rail with 1.2amps)"