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Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 10:39 am
by 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 (412.05 KiB) Viewed 4694 times
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!
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 11:39 am
by 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.
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 12:08 pm
by derkom
kodak80 wrote: ↑Wed Sep 19, 2018 11:39 am
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.
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 12:13 pm
by 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.
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 12:20 pm
by 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
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 12:54 pm
by derkom
...and it's done.
+12V ripple before...
- MZK8UfN.jpg (37.97 KiB) Viewed 4673 times
...and after...
- IMG_20180919_145713.jpg (37.37 KiB) Viewed 4672 times
50 mV/div in both cases.
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 1:20 pm
by exxos
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 2:45 pm
by Atarian Computing
derkom wrote: ↑Wed Sep 19, 2018 12:54 pm
...and it's done.
50 mV/div in both cases.
Cool, so from 250mVpp to 100mVpp? What kind of load are you running here?
Re: Recapping Falcon PSU - My rectifier is different
Posted: Wed Sep 19, 2018 5:24 pm
by derkom
Atarian Computing wrote: ↑Wed Sep 19, 2018 2:45 pm
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)"