So, I got this PSU from a computer I picked up off of Craigslist last summer. I can't find a date code of when it was built. There is nothing on the warranty sticker or the caps to help me find out. However, I can only assume it is as old as the Intel D845WN Pentium 4 motherboard it was powering, which is from 2001. The PC looks like an original build and didn't appear to have been modified in its life, so I don't think my guess is wrong.
Anyways. Most of you probably know how I do this now with the pictures and descriptions. If you want to skip some reading, then just open the pictures and skip to the Summary section. Here is a picture of the back of the PSU:
![](https://www.badcaps.net/filedata/fetch?id=2184350)
And here is the label of the PSU to see who made it:
https://www.badcaps.net/forum/attach...1&d=1443215464
Hmm, the model number says MPT-301? Macron?! But where is Macron's UL number and the Macron-specific "AMD Intel / ATX12V TEST PASS" sticker?
I tell you what – this PSU definitely is not a Macron. Just look at that QC sticker (on the side of the PSU) and the fan grille again in the first picture. Seems familiar?
If anyone said Channel Well, you got it right. That specific QC sticker is the big giveaway (with the multiple stamps). They are just trying to trick us again like they did with the TurboLink PSU I have (which had a Deer UL number). And now I will give you some proof of that – strip the PSU naked!
https://www.badcaps.net/forum/attach...1&d=1443215464
At first, it looks like a Deer or L&C. In particular, you just don't see the TPS3510 supervisory IC like you do with other ISO units. However, the output caps being all Fuhjyyu and the 5VSB design strongly suggest CWT ISO series. Sure there are no "ISO": marking next to the fuse, but that is most likely because this design is a very early version of the ISO series, or perhaps a close cousin.
Either way, it is definitely not the best CWT build quality. Some things to note in the above picture: lack of input filtering, thin 300V, 20 AWG wire on the primary side, bulged caps, and lack of 3.3V torroid (suggesting cheap linear regulation.) Another (not visible) downside: the fan – Rulian Science RDM8025SA, rated for 12 V and 0.13 A… and almost seized
.
But hey, at least there are some PI coils on the secondary side. In fact, almost each rail has one… well, almost
(will cover that "surprise" in a bit.) As for the soldering, it is overall decent and the gaps between high voltage traces on the primary side are good. Here is a picture:
https://www.badcaps.net/forum/attach...1&d=1443215464
Oh, and most notable thing in the entire PSU is the 12V rail filter cap: a Fuhjyyu TNR 16V, 1650 uF cap!
.
![](https://www.badcaps.net/filedata/fetch?id=2184354)
Seriously, what's up with that capacity?
They could have easily advertised it as both a 1500 uF or 1800 uF cap, and it would still have been within 20% tolerance either way. But I guess that is Fuhjyyu quality for you. And now I have this rare sample in my collection box
.
Finally, there is the surprise: that big, white, wirewound resistor. At first, I thought it was a load resistor of some sort. But it is rated for 0.035 Ohms resistance and 10 Watts, so no way it can be a load resistor (even on the 3.3V rail, such resistor would pull 311 Watts!) Instead, it is actually used in place of the PI coil for the 3.3V rail. Why? - I have no idea. Perhaps to stabilize regulation of the 3.3 V rail since they used only a single 1x Fuhjyyu TNR 16V, 220 uF cap for filtering?
Regardless, I just replaced it with a proper PI coil (since the PCB is marked for one anyways) and changed the 220 uF filtering cap with a 1500 uF one (which I am planning on changing it again, likely for a 2200 uF cap). 3.3V regulation is achieved in a linear fashion with a MOSFET, so the output should be pretty clean either way.
Summary
Primary Side:
https://www.badcaps.net/forum/attach...1&d=1443215464
- RS405 bridge rectifier (rated for 4 Amps), no input filtering at all
- two Fuhjyyu LP 200V, 680 uF, 22 x 40 mm (dia. x h) bulk caps
- two 2SC2625 NPN BJT transistors (TO-3P package) for the main PS
- two Fuhjyyu TNR 50V, 2.2 uF, 5 x 11 mm electrolytic caps for the BJT drive circuit
- 2SC5353 NPN BJT for the 5VSB main switch, used in a 2-transistor design
- critical 5VSB cap: Fuhjyyu TNR 50V, 1 uF, 5 x 11 mm, electrolytic
- main transformer appears to be slightly wider than size 35, but also slightly shorter.
Secondary Side:
https://www.badcaps.net/forum/attach...1&d=1443215464
3.3 V rail:
- Linearly regulated from 5 V rail with 40NF03 MOSFET (100V, 35A @ 100C)
- 1x Fuhjyyu TNR 16V, 220 uF, 6.3x11 mm on the output.
- 15-Ohm load resistor
- 0.035-Ohm, 10W resistor instead of a PI coil on the output![Lolsign](https://cdn.badcaps-static.com/images/smilies/lolsign.gif)
5 V rail:
- D83-004 (30A. 40V) schottky rectifier
- 2x Funjyyu TMR 10V, 1000 uF, 10x20 mm caps with a PI coil (8 mm core, 6 turns) between them
- 150-Ohm load resistor
12 V rail:
- STPR1620CT (16A, 200V) fast recovery rectifier
- 1x Fuhjyyu TNR 16V, 1650 uF
, 10x23 mm cap with a PI coil (6 mm core, 20 turns) before it.
- 470-Ohm load resistor
-12 V and -5 V rails:
- 4x FR153 1.5 Amp ultrafast diodes (two per -5 V and -12 V)
- 1x Fuhjyyu TNR 16V, 220 uF cap (for each rail) with a PI coil (3-4 mm core, 34 turns) before it.
- the -5 V rail has a 150-Ohm load resistor and -12 V rail has 470-Ohm load resistor.
5 VSB rail:
- FR-302 (3A @ 75C) fast recovery rectifier
- 2x Funjyyu TNR 16V, 470 uF, 8x14 mm caps with a PI coil (4 mm core, 16 turns) between them
- 10-Ohm, 3-Watt load resistor!
5VSB section:
Like with the other two CWT units, I decided to take some time again to draw the 5VSB circuit. See below:
![](https://www.badcaps.net/filedata/fetch?id=2184357)
All I have to say about this circuit is that it is very similar to the other two CWT PSUs I posted. It is a 2-transistor design with a 1 uF, 50 V critical cap.
Some 5 VSB load tests:
- With no load, the PSU 5VSB circuit was drawing 5.3 Watts @ 0.60 PF. Output voltage stable at 5.13 V.
- With a 1.1 A load (incandescent light bulb), the 5VSB was drawing 20 Watts @ 0.49 PF and output voltage dropped to 4.85 V.
The worst part about this circuit is the 10-Ohm minimum load resistor on the 5VSB rail – it draws 2.5 Watts all of the time. It may seem like nothing, but considering the size of that resistor, it can really make it hot. Just look at what the resistor solder points did on the isolating plastic sheet under the PCB:
![](https://www.badcaps.net/filedata/fetch?id=2184358)
Overall…
This is not that terrible of a PSU, especially considering the fact that it was still working with bad caps up to the point I went to pick it up. So what I did is I (temporarily) recapped the 3.3 V, 5 V, and 12 V rail with some Chemicon KZJ 16 V, 1500 uF, 10 mm dia. caps (and yes, I am aware that they are crappy caps, but I had just pulled them from a dead Xbox 360 motherboard the previous day and they tested okay on the ESR meter.) I am also aware those are some very low ESR caps not quite suitable for PSUs. But I figured this would be a good experiment. Surprisingly, the PSU did not oscillate at all and powered that Intel D845WN motherboard fine again. The other modifications I did were to swap the 10-Ohm 5 VSB dummy load resistor with 75 Ohms and put a proper PI coil (again, from an Xbox 360 motherboard) in place of the 0.035-Ohm wire-wound resistor on the 3.3 V rail. Here is a picture of the temporary "repair":
https://www.badcaps.net/forum/attach...1&d=1443215464
I did not run the PSU for too long though, since I have not fixed the seized fan yet. But when I do, I will test it for a bit longer. For right now, I just know that it is working "fine". Given that the primary transistors are 2SC2625 BJTs, I think the PSU is worth recapping and fixing.
Anyways. Most of you probably know how I do this now with the pictures and descriptions. If you want to skip some reading, then just open the pictures and skip to the Summary section. Here is a picture of the back of the PSU:
And here is the label of the PSU to see who made it:
https://www.badcaps.net/forum/attach...1&d=1443215464
Hmm, the model number says MPT-301? Macron?! But where is Macron's UL number and the Macron-specific "AMD Intel / ATX12V TEST PASS" sticker?
I tell you what – this PSU definitely is not a Macron. Just look at that QC sticker (on the side of the PSU) and the fan grille again in the first picture. Seems familiar?
If anyone said Channel Well, you got it right. That specific QC sticker is the big giveaway (with the multiple stamps). They are just trying to trick us again like they did with the TurboLink PSU I have (which had a Deer UL number). And now I will give you some proof of that – strip the PSU naked!
https://www.badcaps.net/forum/attach...1&d=1443215464
At first, it looks like a Deer or L&C. In particular, you just don't see the TPS3510 supervisory IC like you do with other ISO units. However, the output caps being all Fuhjyyu and the 5VSB design strongly suggest CWT ISO series. Sure there are no "ISO": marking next to the fuse, but that is most likely because this design is a very early version of the ISO series, or perhaps a close cousin.
Either way, it is definitely not the best CWT build quality. Some things to note in the above picture: lack of input filtering, thin 300V, 20 AWG wire on the primary side, bulged caps, and lack of 3.3V torroid (suggesting cheap linear regulation.) Another (not visible) downside: the fan – Rulian Science RDM8025SA, rated for 12 V and 0.13 A… and almost seized
![Razz](https://cdn.badcaps-static.com/images/smilies/icon_razz.gif)
But hey, at least there are some PI coils on the secondary side. In fact, almost each rail has one… well, almost
![LOL](https://cdn.badcaps-static.com/images/smilies/lol.gif)
https://www.badcaps.net/forum/attach...1&d=1443215464
Oh, and most notable thing in the entire PSU is the 12V rail filter cap: a Fuhjyyu TNR 16V, 1650 uF cap!
![Lolsign](https://cdn.badcaps-static.com/images/smilies/lolsign.gif)
Seriously, what's up with that capacity?
![shrug](https://cdn.badcaps-static.com/images/smilies/dunno.gif)
![Rejoice](https://cdn.badcaps-static.com/images/smilies/bigclap.gif)
Finally, there is the surprise: that big, white, wirewound resistor. At first, I thought it was a load resistor of some sort. But it is rated for 0.035 Ohms resistance and 10 Watts, so no way it can be a load resistor (even on the 3.3V rail, such resistor would pull 311 Watts!) Instead, it is actually used in place of the PI coil for the 3.3V rail. Why? - I have no idea. Perhaps to stabilize regulation of the 3.3 V rail since they used only a single 1x Fuhjyyu TNR 16V, 220 uF cap for filtering?
![LOL](https://cdn.badcaps-static.com/images/smilies/lol.gif)
Summary
Primary Side:
https://www.badcaps.net/forum/attach...1&d=1443215464
- RS405 bridge rectifier (rated for 4 Amps), no input filtering at all
- two Fuhjyyu LP 200V, 680 uF, 22 x 40 mm (dia. x h) bulk caps
- two 2SC2625 NPN BJT transistors (TO-3P package) for the main PS
- two Fuhjyyu TNR 50V, 2.2 uF, 5 x 11 mm electrolytic caps for the BJT drive circuit
- 2SC5353 NPN BJT for the 5VSB main switch, used in a 2-transistor design
- critical 5VSB cap: Fuhjyyu TNR 50V, 1 uF, 5 x 11 mm, electrolytic
- main transformer appears to be slightly wider than size 35, but also slightly shorter.
Secondary Side:
https://www.badcaps.net/forum/attach...1&d=1443215464
3.3 V rail:
- Linearly regulated from 5 V rail with 40NF03 MOSFET (100V, 35A @ 100C)
- 1x Fuhjyyu TNR 16V, 220 uF, 6.3x11 mm on the output.
- 15-Ohm load resistor
- 0.035-Ohm, 10W resistor instead of a PI coil on the output
![Lolsign](https://cdn.badcaps-static.com/images/smilies/lolsign.gif)
5 V rail:
- D83-004 (30A. 40V) schottky rectifier
- 2x Funjyyu TMR 10V, 1000 uF, 10x20 mm caps with a PI coil (8 mm core, 6 turns) between them
- 150-Ohm load resistor
12 V rail:
- STPR1620CT (16A, 200V) fast recovery rectifier
- 1x Fuhjyyu TNR 16V, 1650 uF
![LOL](https://cdn.badcaps-static.com/images/smilies/lol.gif)
- 470-Ohm load resistor
-12 V and -5 V rails:
- 4x FR153 1.5 Amp ultrafast diodes (two per -5 V and -12 V)
- 1x Fuhjyyu TNR 16V, 220 uF cap (for each rail) with a PI coil (3-4 mm core, 34 turns) before it.
- the -5 V rail has a 150-Ohm load resistor and -12 V rail has 470-Ohm load resistor.
5 VSB rail:
- FR-302 (3A @ 75C) fast recovery rectifier
- 2x Funjyyu TNR 16V, 470 uF, 8x14 mm caps with a PI coil (4 mm core, 16 turns) between them
- 10-Ohm, 3-Watt load resistor!
5VSB section:
Like with the other two CWT units, I decided to take some time again to draw the 5VSB circuit. See below:
All I have to say about this circuit is that it is very similar to the other two CWT PSUs I posted. It is a 2-transistor design with a 1 uF, 50 V critical cap.
Some 5 VSB load tests:
- With no load, the PSU 5VSB circuit was drawing 5.3 Watts @ 0.60 PF. Output voltage stable at 5.13 V.
- With a 1.1 A load (incandescent light bulb), the 5VSB was drawing 20 Watts @ 0.49 PF and output voltage dropped to 4.85 V.
The worst part about this circuit is the 10-Ohm minimum load resistor on the 5VSB rail – it draws 2.5 Watts all of the time. It may seem like nothing, but considering the size of that resistor, it can really make it hot. Just look at what the resistor solder points did on the isolating plastic sheet under the PCB:
Overall…
This is not that terrible of a PSU, especially considering the fact that it was still working with bad caps up to the point I went to pick it up. So what I did is I (temporarily) recapped the 3.3 V, 5 V, and 12 V rail with some Chemicon KZJ 16 V, 1500 uF, 10 mm dia. caps (and yes, I am aware that they are crappy caps, but I had just pulled them from a dead Xbox 360 motherboard the previous day and they tested okay on the ESR meter.) I am also aware those are some very low ESR caps not quite suitable for PSUs. But I figured this would be a good experiment. Surprisingly, the PSU did not oscillate at all and powered that Intel D845WN motherboard fine again. The other modifications I did were to swap the 10-Ohm 5 VSB dummy load resistor with 75 Ohms and put a proper PI coil (again, from an Xbox 360 motherboard) in place of the 0.035-Ohm wire-wound resistor on the 3.3 V rail. Here is a picture of the temporary "repair":
https://www.badcaps.net/forum/attach...1&d=1443215464
I did not run the PSU for too long though, since I have not fixed the seized fan yet. But when I do, I will test it for a bit longer. For right now, I just know that it is working "fine". Given that the primary transistors are 2SC2625 BJTs, I think the PSU is worth recapping and fixing.
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