Thermal Master TM-350 (the not so gutless wonder)

[dmill89]

Anyone who has purchased a lower-end Coolermaster Case with a PSU included probably found one of these inside of it, so let's see how good or bad it is.


First off it is not a 350w, if you add up the individual rails it comes to 250w, we'll find out why in a moment.



First the input side, there is decent input filtering (only half is on this board the other coil and Xcap are attached the the power connector for a total of 2 Xcaps, 2 Ycaps, and 2 Coils, not the best I've ever seen but considering many PSUs in this class have no input filter at all this isn't too bad.

GBU4G Bridge Rectifier rated at 4A 400V, considering this is a 250W PSU this is defiantly sufficient

A Pair of Canicon 470UF 200V filter caps, I'd prefer 680UF caps although 470s should be ok for a 250W unit.



Decent Sized Coils, Two D304X primary switchers, more than sufficient for a 250W


Now we move on to why this is really a 250W PSU.

One F12C20C Schottky on the 12V rail rated at 12A 200V, Given that this rail is rated at 10A this is just barely sufficient with only 2A of overhead.

Two S20C45C Schottkys each rated at 20A 45V one for the 5V and another for the 3.3V. These rails are rated at 14A each so again a 20A part is sufficient although I would like to see more than 6A of overhead.


Decent sized coils and caps for a 250W PSU although all the caps are either Canicon or Sapcon, not exactly the best brands.

Bottom line this isn't all that bad for a "Free with a Cheap case" PSU. If you stick to the ratings of the individual rails and only use it in a low end system it will probably do ok for an extreme budget build, just don't try to load it up too heavily, and forget about quad core processors or high end video cards. I would however recommend a better unit if budget allows.

Stay tuned for a rebuild, this thing appears to have some potential. I'm planning on swiping the much more substantial secondary rectifiers from a dead Dell Celetronix CX305P (proprietary Dell BTX casing that is slightly larger than standard ATX meaning it won't fit in a normal ATX tower and thus not worth repairing), and upgrading the Caps as well when I get some free time.

[c_hegge]

It's a Sun Pro. If you load it to it's labelled rating, it will explode. I reviewed two similar ones in the HWI el-cheapo PSU roundup.

EDIT: I also load tested a Thermal master 420W PSU. It was also made by Sun Pro. It exploded at 420W load.

[dmill89]

^
I could see this thing potentially doing the 250W you get from adding up the rails, at least for a little while. I agree if you load it to the 350W combined wattage on the label the 12V rectifier will blow up since it is only rated at 12A. I doubt anyone would have to worry about overloading the 5V or 3.3V rails on any modern system although I would like to see more than 20A of capacity on these rails.I could definitely see this thing running a sub 200W Celeron, Pentium dual core, or i3 system with integrated video at least for a few years until the caps fail. These faults are things I will correct when I get around to doing the rebuild.

Again this isn't a great PSU but it is better than most of the Free with sub $50 case PSUs I've seen.

[momaka]

Not too bad indeed. I'm actually pretty surprised Sun Pro made this. Their quality is usually very low.
Post a picture of the underside, if possible. I would like to see how Sun Pro did with the soldering. Judging by this PSU, perhaps they have improved a little.

[dmill89]

Originally Posted by momaka

Not too bad indeed. I'm actually pretty surprised Sun Pro made this. Their quality is usually very low.
Post a picture of the underside, if possible. I would like to see how Sun Pro did with the soldering. Judging by this PSU, perhaps they have improved a little.

Here You Go.


Not the worst I've ever seen, definitely not the best either, looks like they sanded/ground some of the blobs down so they wouldn't short against the case. It also looks like it was hand soldered on an assembly line since the soldering on some parts of the board is better than others.

[momaka]

The only complaint I have about yours above is that the separation between some traces on the primary is a bit too small in certain places. That's typical of Sun Pro, though. But other than that, not too bad. Again, I expected much worse from Sun Pro. The 380W Raidmax I have by them is a complete disaster. And they still make those too!

[Th3_uN1Qu3]

It isn't too bad - look, the transformer is an EI-40. That's a step up from the 33 you usually see in those units. Oughta do 400W if you do the right upgrades.

[dmill89]

I Promised a rebuild and here it is:


Input Side: Now has 2 X 680uf caps, and a GBU6J Bridge Rectifier



Overhead



Rectifiers on secondary: 2x STPR1620CT 16A 200V on 12V rail, 2x STPR3045cw 30A 45V one each on the 5V and 3.3V rail



New Caps on the secondary are UCC KZE except the 2.2uf 50v caps which weren't replaced



New Fan: Sunon KD1208PTS1



Full Listing of Changes / Upgrades:

Input Side:
Bridge Rectifier: GBU4G > GBU6J
Main Caps: 2x 470uf > 2x 680uf

Secondary Rectifiers:
12V: 1x F12C20C > 2x STPR1620CT
5V: S20C45C > STPR3045cw
3.3V: S20C45C > STPR3045cw

Secondary Capacitors:
2x Sapcon 16v 470uf > 2x UCC KZE 16v 680uf
4x Canicon 10v 2200uf > 4x UCC KZE 10v 2200uf
Sapcon 16v 2200uf > UCC KZE 16v 3300uf
Sapcon 16v 1000uf > UCC KZE 16v 2200uf
Canicon 10v 470uf > UCC KZE 10v 1000uf

Fan: Generic sleeve bearing fan > Sunon KD1208PTS1


With the exception of the caps on the secondary all the parts were salvaged from a dead Dell (Celetronix) CX305P-00, the secondary caps were ones I had on hand, nothing was purchased specifically for this rebuild.

[shovenose]

Well cool! Looks good
What's with that tape or something on the primary capacitors?

[dmill89]

Originally Posted by shovenose

Well cool! Looks good
What's with that tape or something on the primary capacitors?

They came out of the dell like that. The tape is really sticky and difficult to remove, and it helped hold them when I was soldering so I left it on. There was more tape on the top (you can see the residue), but I removed that piece to be able to see the tops to make sure they weren't bulging or leaking.

[PeteS in CA]

Wish there was a way to beef up those heatsinks (when it comes to high power heatsinks, heavy metal is definitely your friend!) and replace that O/P inductor -26 material core with a core made with -52 material (powdered iron core materials made by Micrometals), but neither would practical. OTOH, replacing those 4700pF, 2KV Y caps with real 4700pF Y caps would be a good idea, and you might find some in that Dell P/S (made by Delta Products?).

[dmill89]

Originally Posted by PeteS in CA

replacing those 4700pF, 2KV Y caps with real 4700pF Y caps would be a good idea, and you might find some in that Dell P/S (made by Delta Products?).

I Might do that.

The Dell says it is made by a company called Celetronix on the case and when I search the UL number it comes back to a company called EOS Power India PVT LTD. It looks reasonably well built but not as good as a Delta or Lite-On, Probably close in build quality to most HIPROs I've seen. The only thing wrong with it was blown CapXons on the secondary, but since it is a non-standard size which only fits certain Dell BTX towers and I have several Deltas and Lite-Ons in that same size which are better built if I need one for a BTX Dell, so I generally just strip these Celetronix PSUs down for parts.

[dmill89]

Originally Posted by PeteS in CA

replacing those 4700pF, 2KV Y caps with real 4700pF Y caps would be a good idea, and you might find some in that Dell P/S.

I had planned on that however, those plans changed. I pulled the Y caps from the Dell and they only tested at 1800pf(It was a heavily used 7 year old PSU), I tested the Y caps that were in the Thermal Master and they tested at 5400pf so they will be staying at least until I get another junk PSU with good Y caps I can steal. However I did add an extra X cap salvaged from the Dell that tested good. The Thermal Master already had 2 X caps but there was a spot silkscreened on the PCB for an extra one so I added it in.