Rather than post in the PSU build quality pictorial thread, again I am splitting off the recapping info into its own thread. Also, I plan on doing some possible modding/experimentation on this PSU, so I figured that info would also be better to go here.
The PSU in question is this one:
Detailed post with parts and build quality is here:
https://www.badcaps.net/forum/showpo...postcount=3085
So this PSU has very simple output filtering: two 2200 uF caps on each major rail (3.3V, 5V, and 12V.)
Here is a cap diagram showing the caps on each rail:
The 12V rail received 2x United Chemicon KYB, 16,V 2200 uF caps. These are close replacements for the original Teapo SC, in terms of specs.
The 5V rail received 2x Rubycon YXJ, 10V, 2200 uF caps – an excellent match for the two bad Teapo SC 10V, 2200 uF
For the 3.3V rail, I put 1x Rubycon ZLH, 6.3V, 2200 uF cap in place of the BH, 10V, 2200 uF cap. The ZLH is probably very over-kill. But the 3.3V rail of this PSU uses a mag-amp circuit for regulation. Mag-amp circuits usually don’t mind deviations in specs, particularly when lower-ESR caps are used. The second cap on that rail was a Teapo SC, 10V, 2200 uF that was bad. Since my stock of Ruby ZLH caps is getting very low and like to keep a few spare in case of an “emergency repair”, I tested the BH cap on my cap meter, determined it is still OK, and put it on the second (output) position. The Ruby ZLH should be handling most of the ripple/filtering, so that BH cap may not be stressed as much.
For the -12V rail, the original cap was a single FCon GF, 16V, 100 uF. There is no 7912 linear regulator, but there is a PI coil. Still, I think 100 uF is way too little, despite the fact that the -12V rail is not really used anymore. So I replaced that cap with a Nichicon PM, 16V, 220 uF cap in 8x13 mm can. I was thinking of even using a Nichicon PJ, 16V, 470 uF… and honestly, I might end up swapping it. But for a “test run” to see how this PSU performs, I figured the upgraded capacity from 100 uF to 220 uF is already a good enough improvement.
Finally, the 5VSB: on this one, I put a Nichicon HN, 16V, 1500 uF cap. This is an ultra-low ESR cap intended for motherboards and not really very tolerant of hot circuits. However, the 5VSB circuit of this PSU uses a DM0265r PWM-FET off-line switch IC, which makes the 5VSB fairly efficient. I measured the PSU drawing about 2 Watts at the wall with an old Pentium 4 motherboard connected (with WOL/WOR disabled for lower power draw.) So with that, there isn’t much heat generated from the 5VSB, and that Nichi HN should be fine. Moreover, 5VSB circuits tend to use flyback topology, which tends to produce a lot of ripple current. The Nichi HN have very high ripple current rating, so the circuit won’t mind. As for the 2nd cap on the 5VSB – this was also a bad 10V, 2200 uF Teapo SC. Removed that and replaced it with the FCon GF, 16V, 1000 uF cap (that was originally in place where the Nichicon HN is now.) Result: 5VSB is happy and stable. No winning noise from the ultra-low ESR of the Nichicon HN cap either.
I also replaced a few small caps, but not every one. On the diagram above, I labeled a “Startup” cap on the primary side. This is for the 5VSB, but obviously the entire PSU will not work at all if that cap was bad. It’s a FCon KM, 50V, 47 uF, 6.3x11 mm. I replaced it with a Nichicon PM 50V, 47 uF, 6.3x11 mm.
Likewise, there is another cap on the diagram above, labeled as “Secondary Auxiliary”. This rail provides power to the PWM chip and BJT driver transistors on the secondary side when the PSU is in Soft-off mode. With this rail unstable, the PSU may either not start or not work right. So it’s better to replace it. This cap is also an FCon KM, 50V, 47 uF like the startup cap. I replaced it with a Nichicon PM, 50V, 47 uF.
And last but not least, there are two Teapo SC, 50V, 6.8 uF caps on the primary that are part of the driver circuit for the main PS BJTs. I didn’t have any 6.8 uF caps in stock, so I tested one of these, found it reading OK, and left it alone for now. It is recommended that these caps are replaced in half-bridge PSUs. I probably could have put together a 4.7 uF and a 2.2 uF cap in parallel for a total of 6.9 uF, but I didn’t feel like diddling around. If I buy caps in the future, I’ll just order some 6.8 uF caps then. Until that time, that is all the recapping I’ve done with this PSU.
For anyone that wants to do an absolute full recap on this PSU, the PSU has these small caps that you will need:
4x 50V, 2.2 uF, 5x11 mm
2x 50V, 10 uF, 5x11 mm
1x 50V, 4.7 uF, 5x11 mm
And here is a picture of my finished PSU recap (at least for now):
Also, a high-res solder-side shot, in case someone has one of these PSUs with SMD resistors burned:
https://www.badcaps.net/forum/attach...1&d=1592073646
In terms of modding, I haven’t done any yet. But I may increase the capacity on the -12V rail to 470 uF, as mentioned. Another thing to look into would be to add a plastic sheet under the back side of the cooling fan to hopefully optimize/improve the cooling inside the PSU better (not sure how good or bad it is right now, but it doesn’t look optimal to me, at least logically thinking about it.) On that note, I might also trace and test the fan controller circuit, and maybe try to improve it. The fan is not super-loud right now, but it is noticeable. Depending on how well the PSU is cooling, I may try to lower its speed a little more, which should improve both noise and put less dust inside the PSU. Not to mention the fan will likely last longer. In regards to that, PSU unit #2 (I bought two of these PSUs) had a seized fan and burned output inductor. Granted there was a ton of dust inside that one, suggesting the PSU ran for many hours, I still think it may have lasted longer if the fan was spinning slower (but enough to cool the PSU.)
So those are the things that can still be improved on this PSU.
I still haven’t fully tested my recapped PSU under a heavier load. But with an old crappy Pentium 4 motherboard and a 2 GHz Pentium 4 Northwood CPU (PC drawing about 60-65 Watts tops), the PSU was running cool, as it should. Given it has a 6-pin and an 8-pin PCI-E power connectors, I should be able to come up with a system that can generate some significant load on the 12V rail.
Again, as mentioned in the build quality pictorial thread, I doubt this PSU can provide 550 Watts of power. It seems well-built, but I think it's probably rated closer to 350-400 Watts, honestly. It will very likely be able to provide up to 300 Watts on the 12V rail, which IMO is enough for a lot of single CPU, single GPU PC builds. And I very likely won't try to push anything more from it.
The PSU in question is this one:
Detailed post with parts and build quality is here:
https://www.badcaps.net/forum/showpo...postcount=3085
So this PSU has very simple output filtering: two 2200 uF caps on each major rail (3.3V, 5V, and 12V.)
Here is a cap diagram showing the caps on each rail:
The 12V rail received 2x United Chemicon KYB, 16,V 2200 uF caps. These are close replacements for the original Teapo SC, in terms of specs.
The 5V rail received 2x Rubycon YXJ, 10V, 2200 uF caps – an excellent match for the two bad Teapo SC 10V, 2200 uF
For the 3.3V rail, I put 1x Rubycon ZLH, 6.3V, 2200 uF cap in place of the BH, 10V, 2200 uF cap. The ZLH is probably very over-kill. But the 3.3V rail of this PSU uses a mag-amp circuit for regulation. Mag-amp circuits usually don’t mind deviations in specs, particularly when lower-ESR caps are used. The second cap on that rail was a Teapo SC, 10V, 2200 uF that was bad. Since my stock of Ruby ZLH caps is getting very low and like to keep a few spare in case of an “emergency repair”, I tested the BH cap on my cap meter, determined it is still OK, and put it on the second (output) position. The Ruby ZLH should be handling most of the ripple/filtering, so that BH cap may not be stressed as much.
For the -12V rail, the original cap was a single FCon GF, 16V, 100 uF. There is no 7912 linear regulator, but there is a PI coil. Still, I think 100 uF is way too little, despite the fact that the -12V rail is not really used anymore. So I replaced that cap with a Nichicon PM, 16V, 220 uF cap in 8x13 mm can. I was thinking of even using a Nichicon PJ, 16V, 470 uF… and honestly, I might end up swapping it. But for a “test run” to see how this PSU performs, I figured the upgraded capacity from 100 uF to 220 uF is already a good enough improvement.
Finally, the 5VSB: on this one, I put a Nichicon HN, 16V, 1500 uF cap. This is an ultra-low ESR cap intended for motherboards and not really very tolerant of hot circuits. However, the 5VSB circuit of this PSU uses a DM0265r PWM-FET off-line switch IC, which makes the 5VSB fairly efficient. I measured the PSU drawing about 2 Watts at the wall with an old Pentium 4 motherboard connected (with WOL/WOR disabled for lower power draw.) So with that, there isn’t much heat generated from the 5VSB, and that Nichi HN should be fine. Moreover, 5VSB circuits tend to use flyback topology, which tends to produce a lot of ripple current. The Nichi HN have very high ripple current rating, so the circuit won’t mind. As for the 2nd cap on the 5VSB – this was also a bad 10V, 2200 uF Teapo SC. Removed that and replaced it with the FCon GF, 16V, 1000 uF cap (that was originally in place where the Nichicon HN is now.) Result: 5VSB is happy and stable. No winning noise from the ultra-low ESR of the Nichicon HN cap either.
I also replaced a few small caps, but not every one. On the diagram above, I labeled a “Startup” cap on the primary side. This is for the 5VSB, but obviously the entire PSU will not work at all if that cap was bad. It’s a FCon KM, 50V, 47 uF, 6.3x11 mm. I replaced it with a Nichicon PM 50V, 47 uF, 6.3x11 mm.
Likewise, there is another cap on the diagram above, labeled as “Secondary Auxiliary”. This rail provides power to the PWM chip and BJT driver transistors on the secondary side when the PSU is in Soft-off mode. With this rail unstable, the PSU may either not start or not work right. So it’s better to replace it. This cap is also an FCon KM, 50V, 47 uF like the startup cap. I replaced it with a Nichicon PM, 50V, 47 uF.
And last but not least, there are two Teapo SC, 50V, 6.8 uF caps on the primary that are part of the driver circuit for the main PS BJTs. I didn’t have any 6.8 uF caps in stock, so I tested one of these, found it reading OK, and left it alone for now. It is recommended that these caps are replaced in half-bridge PSUs. I probably could have put together a 4.7 uF and a 2.2 uF cap in parallel for a total of 6.9 uF, but I didn’t feel like diddling around. If I buy caps in the future, I’ll just order some 6.8 uF caps then. Until that time, that is all the recapping I’ve done with this PSU.
For anyone that wants to do an absolute full recap on this PSU, the PSU has these small caps that you will need:
4x 50V, 2.2 uF, 5x11 mm
2x 50V, 10 uF, 5x11 mm
1x 50V, 4.7 uF, 5x11 mm
And here is a picture of my finished PSU recap (at least for now):
Also, a high-res solder-side shot, in case someone has one of these PSUs with SMD resistors burned:
https://www.badcaps.net/forum/attach...1&d=1592073646
In terms of modding, I haven’t done any yet. But I may increase the capacity on the -12V rail to 470 uF, as mentioned. Another thing to look into would be to add a plastic sheet under the back side of the cooling fan to hopefully optimize/improve the cooling inside the PSU better (not sure how good or bad it is right now, but it doesn’t look optimal to me, at least logically thinking about it.) On that note, I might also trace and test the fan controller circuit, and maybe try to improve it. The fan is not super-loud right now, but it is noticeable. Depending on how well the PSU is cooling, I may try to lower its speed a little more, which should improve both noise and put less dust inside the PSU. Not to mention the fan will likely last longer. In regards to that, PSU unit #2 (I bought two of these PSUs) had a seized fan and burned output inductor. Granted there was a ton of dust inside that one, suggesting the PSU ran for many hours, I still think it may have lasted longer if the fan was spinning slower (but enough to cool the PSU.)
So those are the things that can still be improved on this PSU.
I still haven’t fully tested my recapped PSU under a heavier load. But with an old crappy Pentium 4 motherboard and a 2 GHz Pentium 4 Northwood CPU (PC drawing about 60-65 Watts tops), the PSU was running cool, as it should. Given it has a 6-pin and an 8-pin PCI-E power connectors, I should be able to come up with a system that can generate some significant load on the 12V rail.
Again, as mentioned in the build quality pictorial thread, I doubt this PSU can provide 550 Watts of power. It seems well-built, but I think it's probably rated closer to 350-400 Watts, honestly. It will very likely be able to provide up to 300 Watts on the 12V rail, which IMO is enough for a lot of single CPU, single GPU PC builds. And I very likely won't try to push anything more from it.
Attached Files
I believe there are a few very old posts/threads of the same PSU as my JNC under the names Meico and/or M-tec, IIRC (for anyone curious to see it.) I looked through my junk bin of “crappy, but tested OK” caps and also found some to use as a sacrificial lamb. The result was this:
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