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**b700029** · 03-14-2012, 03:11 AM

Re: Power supply build quality pictorial. part 2

I can see the 2005 chip in that one. It's a Deer/L&C. The discolored PCB was probably not due to the short but the 5VSB circuit in them tends to run hot and do that over time.

Even the cheapest PSUs I've come across will shut down with a dead short, but if the short is of high enough resistance it will happily keep providing power - it doesn't know the difference between a loaded CPU or a wire acting as a heater. And even if it can't do anywhere near 600W, just look at a soldering iron - 60W is enough to generate a ton of heat, and the worst bottom-of-the-barrel gutless wonders are already able to output that much wattage.

**tom66** · 03-14-2012, 10:28 AM

Re: Power supply build quality pictorial. part 2

That AC adapter obviously has a zero point module or something in it because it can consume 0.15Ap-p (0.1A) at 100V (10W) and yet output 5V @ 6000mA = 30W. Obviously the 10W is used to excite the neutron scattering in the ZPM.

**tom66** · 03-14-2012, 11:32 AM

Re: Power supply build quality pictorial. part 2

Power supply from a Sony professional VCR circa 1995. Another skip find, but one of the main processors has been a bit fried (I think) so not worth repairing.

The VCR itself is rated for 35W maximum input. There's a board with this PSU module soldered on, the module is made by Mitsumi, and the PSU board is a Sony.

Excellent line filter (two X caps, two coils, five Y caps) and a huge 100uF bulk capacitor. Obviously not much concern for low cost here. Bulk cap is a Rubycon. There's a 4.7 ohm resistor to limit inrush.

Mitsumi board has a HUGE transformer on it - bigger than a transformer on a computer PSU rated at 250 watts!

Outputs are 13V @ approx 1A, 6V @ approx 2A and -8V @ approx 200mA. Ratings guessed from external fuses. (Yes, each output is fused.) So that's ~27W. 13V and -8V are labelled as unregulated; feedback is taken from 6V, but it seemed pretty stable to me.

Huge power transistor and heatsink made of -copper-.

Looks like three transistors drive the main power NPN: 2SC4236. It's a four transistor power supply then. Not as optimal as the MOSFET + NPN ringing choke converter seen in cheap PSUs.

Attached Files

**b700029** · 03-14-2012, 11:37 AM

Re: Power supply build quality pictorial. part 2

Low switching frequency = large transformer.

**tom66** · 03-14-2012, 11:45 AM

Re: Power supply build quality pictorial. part 2

Originally posted by b700029 View Post

Low switching frequency = large transformer.

That's what I was figuring. But the huge transistor and heatsink (given it's quite a low power device) seem to contradict that. At that level of power, the only reason for using a big transistor would be because switching losses were higher. Or maybe it's just for reliability?

That transformer in the picture is from an L&C/Deer, so of course it's going to be tiny.

**momaka** · 03-14-2012, 02:30 PM

Re: Power supply build quality pictorial. part 2

Originally posted by b700029 View Post

I can see the 2005 chip in that one. It's a Deer/L&C.

It's a Deer/L&C indeed. Those YC caps are pretty much a trademark of low-end Deer/L&C (now Solytech) units.

I had a similar one (L&C LC-B300ATX, "2003" PWM chip) do the exact same thing with the wires. The short started at the floppy drive connector. Luckily, I was there when I turned on my computer and my case was open, so as soon as I saw smoke coming from the floppy drive wires, I quickly unplugged the computer from the wall. It took me a few seconds to do that and by that time, the wires going to the CD-ROM drive right above the floppy drive started to melt as well.

In my case, it wasn't the floppy drive that shorted though. In fact, there was nothing shorted actually. I tried every single component in that computer and everything tested good afterwards, including the floppy drive and power supply!

I think one possible explanation for this is crummy floppy drive connectors - perhaps they just short out internally or something like that. But why this PSU burned that day is still a mystery to me

.

I still have a whole collection of pics of various Deer and L&C units that I haven't uploaded here. Should do that some day.

**goodpsusearch** · 03-14-2012, 03:19 PM

Re: Power supply build quality pictorial. part 2

Originally posted by momaka View Post

I still have a whole collection of pics of various Deer and L&C units that I haven't uploaded here. Should do that some day.

I encourage you to do that

**ben7** · 03-14-2012, 03:30 PM

Re: Power supply build quality pictorial. part 2

Originally posted by goodpsusearch View Post

I encourage you to do that

Same here

-Ben

**momaka** · 03-15-2012, 12:18 PM

L&C Technology Inc. LC-250ATX

Alright, as per popular demand here, I decided to post my entire Deer/L&C collection (split into multiple posts below, so give me a few minutes as I post each).
….

Let’s imagine it’s 1999. In front of you below is a fresh out-of-the-factory North American Deer/L&C Technology sample. Plain and gray.
https://www.badcaps.net/forum/attach...1&d=1331835289

Next is a shot of the label. As the LC-250ATX model number suggests, we got us a 250W PSU. Those of you with the sharp eyes might have noticed the typo on the label for the 5VSB wattage. Apparently 5V x 0.8A is 5W.

https://www.badcaps.net/forum/attach...1&d=1331835289

And a top shot… (note: I disconnected the primary wires in this pic.)
https://www.badcaps.net/forum/attach...1&d=1331835289
Initial impressions: it’s not quite gutless (especially for powering 1999’s computers) but you can still tell corners were cut. There’s a lame choke for the primary input filtering, 2x 1 KV ceramic caps instead of proper Y caps, metallized polypropylene film cap instead of a X cap, and no insulating plastic sheet between case and PCB. On the not so bad side, there’s a RS405 bridge rectifier good for 4 Amps, 2x 200V 470uF primary caps (made by VIVA), 2x 13007 switching transistors, and C5027 for the 5vsb transistor. Text in the middle of the board says DR-240ATX. Fan is a CBE CB802512M 12V fan rated at 0.14A. Looks and feels exactly the same as a Rulian Science & Technology fan, though. All wires are 20 AWG. No P4 connector is included with this PSU (then again, this is in 1999

)
The bottom side:
https://www.badcaps.net/forum/attach...1&d=1331835289
The soldering is not great but still very acceptable. No long leads sticking out. There is some discoloration under the primary side of the 5vsb circuit and the secondary under the PWM controller. So let’s have a look at the top side again, this time the secondary…
https://www.badcaps.net/forum/attach...1&d=1331835289
PWM controller is DBL494. 5VSB transformer is properly sized.
3.3V rail: 2x bulged 2200uF 10V VIVA caps (no PI coil in between), 1x S10C40C 10A schottky rectifier, 4(?) Ohm 3W dummy load resistor.
5V rail: 1x 2200uF 10V VIVA cap (after PI coil), 1x 220uF 16V VIVA cap (before PI coil), 1x S16C20C 16A schottky rectifier, 47 Ohm 1W dummy load resistor.
12V rail: 1x 2200uF 16V Su’scon SD, BYQ28E-200 10A FR rectifier, 100 Ohm 2W dummy load resistor
-5V and -12V rails: 1x each 470uF 16v VIVA caps, 1x each PI coils, 2x each 1A or 1.5A FR diode rectifiers
5VSB: 2x 100uF 16V Jun Fu HK (1x before 7805 regulator, 1x after it), 7805 regulator for output, FR154 FR diode rectifier.

As the 7805 regulator might suggest, the 5VSB circuit in this PSU is self-oscillating. However, unlike the 2-transistor design, this circuit does not have feedback (hence the lack of optocoupler next to the 5VSB transformer). That doesn’t mean this circuit can’t go over-voltage – it can, but the 7805 regulator will (in most cases) protect the motherboard from damage. Like some of the 2-transistor self-oscillating designs, this circuit also has a critical cap on the primary – 22uF, 25V Su’scon SK in this case.

In fact, the 5VSB might actually have gone over-voltage before. Originally, I got this PSU from the trash. Apparently one of the small caps had exploded inside since there was paper and foil scattered everywhere. The base of the exploded cap is still there, though. Some of you may have already spotted that in the pictures. More particularly, look again at the last one above. To the right of the PWM controller is a green polypropylene cap, and next to it is the base of the exploded cap (the rubber bung with the 2 metal “probes” sticking out). Also note the secondary heatsink right above that cap and how one of the fins is bent. This exploded cap is actually responsible for filtering power going to the PWM controller, which is provided by the 5VSB transformer. My theory is voltages from the 5VSB transformer most likely went over-voltage and made that cap explode. And this doesn’t seem to be a unique case either. I have seen the exact same model of this PSU (here, on BCN) with the exact same cap exploded. Maybe even twice.

But other than that, this PSU is not so horrible. I already changed the critical and exploded caps and the PSU runs okay now (without load, of course – won’t try it on any computer with those bulged caps). The spot for the exploded cap holds a 47uF 50V cap.

Stay tuned. More Deer coming your way

.

Attached Files

**momaka** · 03-15-2012, 12:26 PM

Deer DR-250ATX

Next we have a 2001 “vintage” – another North American Deer. This one came with a computer case.
As usual, the outside first (note: the holes on the top and back of the casing are not original – I made those after I recapped it):
https://www.badcaps.net/forum/attach...1&d=1331835740
https://www.badcaps.net/forum/attach...1&d=1331835740

And the label:
https://www.badcaps.net/forum/attach...1&d=1331835740
It looks like they fixed the typo with the 5VSB wattage rating. Yet again another 250W PSU. Next, a shot of the guts.
https://www.badcaps.net/forum/attach...1&d=1331835740
This one doesn't seem too bad at all. Decent heatsinks (for 250W), 1x X cap, 2x Y caps, a proper primary input choke, 35 –sized main transformer, 600V –rated wires on the primary, 0.14A Powerlogic fan, dual pole ON-OFF switch. Even the fuse is in a fuse holder.
Primary side:
https://www.badcaps.net/forum/attach...1&d=1331835740
KBL405 bridge rectifier good for 4 Amps, 2x 200V 470uF JEE primary caps, properly –sized 5VSB transformer, and again standard transistors in a TO-220 package.
Bottom Side:
https://www.badcaps.net/forum/attach...1&d=1331835740
Soldering is decent and looks shiny. Some of the components did have slightly longer leads, though. And again we have some discoloration – mostly due to the load resistors on the secondary, although the resistors providing power to the PWM IC also seem to have been running a bit hot.
Secondary side:
https://www.badcaps.net/forum/attach...1&d=1331835740
Before you jump out of your chair - no, those Chemicon KY caps are not original to the PSU. In fact, all of the pics shown here are after I modified the PSU (except the underside pic). PWM controller is a proprietary DR-0183 chip.
Originally:
3.3V rail: 2x 2200uF 10V SC (or is it CS) caps (before and after PI coil), not sure about rectifier (might have been 10A schottky), 10 Ohm 2W dummy load resistor.
5V rail: 2x 2200uF 10V SC caps (before and after PI coil), 20A schottky rectifier, forgot what load resistor.
12V rail: 1x 2200uF 16V Jun Fu WG, 6A 200V FR rectifier, 100 Ohm 2W dummy load resistor.
-5V and -12V rails: 1x each 470uF 16V Rulycon caps, 1x each PI coils, 2x each 1.5A or 2A FR diode rectifiers
5VSB: 2x bulged 1000uF 10V Rulycon caps (before and after PI coil), 3A FR diode rectifier, 1(?) KOhm dummy load resistor.

Modified:
3.3V rail: changed load resistor with 100 Ohm 2W (from 12V rail). Caps still need to be changed.
5V rail: changed caps to 2x 2200uF 10V United Chemicon KY and load resistor to 150 Ohm ½ W.
12V rail: changed load resistor to 2x 1 KOhm ½ W in parallel
-5V and -12V rails: put 1x 1000uF 10V CapXon KM (reused) on -5V rail, and 1x 470uF 16V CapXon KM (reused) on -12V rail.
5VSB: 2x 1000uF 6.3uF United Chemicon KY caps

Also changed a lot of small caps with Panasonic FC, including the critical cap (22uF 50V Rulycon) and the primary transistor driving caps (10uF 50V). As a result, PSU runs great now in the Pentium 3 PC that's in my grandmother's house. 5VSB reads 5.00V exactly (5.01V when system is running), 5V rail reads 5.04 to 5.11V depending on CPU load, 3.3V rail reads 3.32 to 3.34V depending on CPU load, 12V rail reads 12.09 to 12.26V depending on CPU load, -5V rail reads -5.11V steady, -12V rail reads -11.7 to -11.9V depending on load. All voltages are rock stable when the system is not transitioning between load and no load. Overall a decent PSU. The wires are still only 20 AWG, though and again no P4 connector (so the 6A rectifier on the 12V shouldn't worry you that much).

Attached Files

**momaka** · 03-15-2012, 12:38 PM

LC-235ATX and LC-B300ATX

Let’s look at some Eastern European L&C samples now – a LC-235ATX (235W) from 2001 and a newer (2003?) LC-B300ATX (300W). These are probably the cheapest of the cheapest you can find from L&C. The B300ATX I got for 7 Euro (or thereabouts) when I was building a PII PC for use in my grandmother’s house. The 235ATX was in use in my cousin’s computer for a few years before he gave me his old computer.
Outside, 1st and 3rd pictures (LC-235ATX on the left, LC-B300ATX on the right), 2nd picture (LC-235ATX on top, LC-B300ATX on bottom).
https://www.badcaps.net/forum/attach...1&d=1331836529
https://www.badcaps.net/forum/attach...1&d=1331836529
https://www.badcaps.net/forum/attach...1&d=1331836895

Let’s start with the LC-235ATX… top side and primary side:
https://www.badcaps.net/forum/attach...1&d=1331836529
https://www.badcaps.net/forum/attach...1&d=1331836529
Missing input choke and X cap, 1KV ceramic caps, 1.5A diodes for the bridge rectifier (that’s a bit low, but still okay for 230V line use), average gutless-wonder TO-220 transistors mounted on somewhat whimpy primary heatsink, 33 -sized transformer, KA7500 PWM controller, LM339N quad comparator (for OVP and UVP)
And the underside:
https://www.badcaps.net/forum/attach...1&d=1331836529
Again, acceptable soldering and no long or untrimmed leads. And the secondary:
https://www.badcaps.net/forum/attach...1&d=1331836529
3.3V rail: 2x 1000uF 10V Jun Fu WG (before and after PI coil), not sure about rectifier (probably 10A schottky), 4.7(?) Ohm 3W dummy load resistor, and another PI coil instead of a choke!
5V rail: 1x 1000uF Jun Fu WG (after PI coil) and 1x 220uF 10V CapXon KM (before PI coil), B1545 15A schottky rectifier, 47 Ohm 1W dummy load resistor.
12V rail: 1x 1000uF 16V CapXon KM, 6A diodes-on-a-bracket “rectifier”

(2x 3A FR diodes), 100 Ohm 2W dummy load resistor.
-5V and -12V rails: 1x each 470uF 16V CapXon KM caps, no PI coils installed, 2x each 1A or 1.5A FR diode rectifiers.
5VSB: 2x 100uF 16V Jun Fu HK (1x before 7805 regulator, 1x after it), 7805 regulator for output, 1.5A FR diode rectifier.

Like the 1999-built Deer, this one uses a 7805 linear regulator in a self-oscillating 5VSB circuit with no feedback as well (again, note the lack of an optocoupler). Hence, why it still works fine after so many years. The fan, a Powerlogic PL80S12M, is wired in series with a 10 Ohm resistor to the 12V rail – it’s been running near full speed all these years without problem (probably explains why none of the caps have gone bad either).

And now the LC-B300ATX - top side and primary, that is:
https://www.badcaps.net/forum/attach...1&d=1331836529
https://www.badcaps.net/forum/attach...1&d=1331836529
Looks almost unused, doesn’t it? Well, that’s the PSU I was talking about it post #486. In nearly 3 years of use (about 1 month only of each year), I was forced to change it back to the LC-235ATX after the wires shorted/smoked because I just didn’t trust it anymore. This thing was actually making my (at that time) PII computer restart when I tried to play some 3D games. When I upgraded that computer to a Pentium 3, the PSU would usually make it boot-loop instantaneously 3 times on a cold boot (the CD-ROM would seek 3 times after turning the PC on) and the computer would restart with a very heavy load.
As you can see, for 300W, it’s very gutless. But regardless of the wattage rating, this PSU too has missing input filtering just like the other LC above and same lame 1KV ceramic caps. At least the bridge rectifier is made of 3A diodes. Primary caps are 200V 470uF YC units. Main transformer is 33 –sized instead of 35, 5vsb transformer is tiny, and there are jumpers for just about every coil and choke. Only the heatsinks are not too bad. Note that the position of the primary and the secondary are switched as opposed to a regular PSU – this is what the “B” in the model number signifies.
Next, the bottom side:
https://www.badcaps.net/forum/attach...1&d=1331836529
Very decent soldering, especially for its price. Only 1 or 2 leads were slightly longer.
Finally, a shot of the components on the secondary side (or lack of, that is):
https://www.badcaps.net/forum/attach...1&d=1331836529
Yup, not much to talk about here. Each rail has only a single cap and absolutely no PI coils. Explains why my computers were boot-looping. PWM controller is labeled “2003”.
3.3V rail: 1x 2200uF 10V YC cap, no PI coil, 10 A schottky rectifier, 6.9 Ohm 2W dummy load resistor
5V rail: same as 3.3V rail, but it has a 20A schottky and not sure on the load resistor.
12V rail: 1x 2200uF 16V YC cap, no PI coil, 10A FR rectifier, no idea what load resistor.
-5V and -12V rail: 1x each 470uF (?) 16V cap, no PI coils
5VSB: 1x 1000uF(?) 10V Koshin KH cap, 1 or 1.5A FR diode, no PI coil
Fan is a crummy sleeve bearing Rulian Science & Technology RDM8025SA rated at 0.13A. 5VSB circuit is standard 2-transistor affair.
I might rebuild it some day, just so I have a spare PSU for testing computers when I go to my grandmother’s house.

Attached Files

**momaka** · 03-15-2012, 12:44 PM

Another L&C…

Finally we have another even newer L&C, possibly from 2005 or 2006. Not sure what model or wattage, though, since I got it from a repair place for free without the top cover. So skip to top side and primary:
https://www.badcaps.net/forum/attach...1&d=1331836895
https://www.badcaps.net/forum/attach...1&d=1331836895
Hey, I see some filtering on the primary. Unfortunately, it’s still just a crappy coil and a polypropylene cap. Y caps might actually be real Y caps, but I didn’t see any certifications on them so they are as good as the 1KV ceramic caps to me. 3A diodes for a bridge rectifier, 200V 330uF YC primary caps, somewhat smaller heatsinks, 33 –sized transformer with a “35” label (nice try L&C), 16 –sized 5VSB transformer with a “19” label *sigh*, and a “2005” PWM IC. The missing PI coils were actually installed in this PSU but I removed them since the PSU had a bad fuse and also because the PI coils were actually bypassed with the traces on the PCB. Yes,

.Let me show you a picture of it that I posted in another thread. Click on link below (it’s not uploaded at the bottom of this post).
https://www.badcaps.net/forum/attach...4&d=1286064227
Again, I don’t know what to say about this other than

. Anyways, let’s move to the secondary side…
https://www.badcaps.net/forum/attach...1&d=1331836895
Looks like a bit of an improvement in some areas and not so much in others compared to the other L&C units above. The chokes for the 5V/12V and 3.3V rails look better (the 3.3V choke has more turns, and the 5V/12V choke has 2 wires for the 12V rail).
3.3V rail: 2x 1000uF 10V YC caps (3.3V PI is bypassed), can’t remember what rectifier was used – probably 10A or maybe 15A schottky rectifier, 10 Ohm 3W load resistor.
5V rail: 2x 1000uF 10V YC caps (1x before and 1x after PI coil – PI coil is not bypassed), 30A schottky rectifier, no idea on loading resistor.
12V rail: 1x 1000uF 16v YC cap, bypassed PI coil, 10A FR rectifier, 100 Ohm load resistor.
-12V rail (-5V rail is not installed): 1x 470uF 16V YC cap, jumper instead of PI coil, 2x 1.5A FR diodes for rectification, 510 Ohm ½ W load resistor.
5VSB rail: 2x 1000uF 10V YC caps, bypassed PI coil, 3A FR diode - all in a standard 2-transistor circuit.

I can’t really comment much about the functionality of this PSU, since it was given to me with a blown fuse and I never really bothered to try to fix it. The primary side and transistors weren’t shorted when I measured them (perhaps they went open circuit). There’s a burn mark on the bottom of the case that lines up with a burn mark on the primary side (not show in the pictures). Maybe a surge killed this? Well, in any case, I don’t think I’ll be fixing it. Just not worth it. The PCB underside has too many long leads. I might reuse the wires, though – they are actually 18 AWG. There’s also a P4 connector.

By the way, last picture is for the two L&C supplies in my last post. Couldn't upload it in that post due to limitation on # of attachements so I put it here.

Attached Files

**Th3_uN1Qu3** · 03-15-2012, 02:19 PM

Re: Another L&C…

Originally posted by momaka View Post

The missing PI coils were actually installed in this PSU but I removed them since the PSU had a bad fuse and also because the PI coils were actually bypassed with the traces on the PCB. Yes,

Seen it before. Really funny... they actually bothered to put the missing parts in there but forgot that they changed the PCB so that they don't have to bother using wire jumpers in the units without pi filters.

**ben7** · 03-15-2012, 02:21 PM

Re: Another L&C…

Originally posted by Th3_uN1Qu3 View Post

Seen it before. Really funny... they actually bothered to put the missing parts in there but forgot that they changed the PCB so that they don't have to bother using wire jumpers in the units without pi filters.

haha! BIG lol!

-Ben

**goodpsusearch** · 03-15-2012, 03:08 PM

Re: L&C Technology Inc. LC-250ATX

Originally posted by momaka View Post

metallized polypropylene film cap instead of a X cap,

Is this bad??? This is the first time I read it here. I have some Maxpower psus with "brown" caps used for X caps...

Can you explain?

**c_hegge** · 03-15-2012, 03:12 PM

Re: Power supply build quality pictorial. part 2

Unsolder the transformer inthat last one. Often, they say ERL-35 on top and ERL-33 underneath

**PeteS in CA** · 03-15-2012, 03:28 PM

Re: Power supply build quality pictorial. part 2

Is this bad??? This is the first time I read it here. I have some Maxpower psus with "brown" caps used for X caps...

Can you explain?

I think momaka's meaning is that the caps used were not safety-agency approved polypropylene caps.

**tom66** · 03-15-2012, 03:45 PM

Re: Power supply build quality pictorial. part 2

A proper, safety approved and tested X capacitor will not flame on surge or end of life. (It may burn and smoke, but that's all that is allowed, and it should extinguish after 30(?) seconds.)

A proper Y capacitor is guaranteed not to short under any failure mode. If the Y caps short, it poses an electric shock hazard as the case becomes energised with one side of the line - especially so if the earth is broken, damaged or deliberately removed.

A brown polypropylene capacitor may be okay for a line filter, but it won't meet the flammability test, so could pose a fire hazard. Then again, most L&C/Deer supplies are a fire hazard in many other ways, so it wouldn't make much of a difference.

I've actually got two L&C supplies in the junk pile. Both of them look like that last photo, except one of them is obviously the "Lite" edition as it is missing many more components and with a few slimmed down to reduce the weight. The 470uF primary caps by the way tested at 330uF on my ESR cap meter - both of them - w/ESR about 0.11 ohms. And if it wasn't enough of a coincidence, the 330uF primary caps in the "Lite" edition tested at 220uF 0.13 ohms each (those were in the PC with the 100 Hz ripple, so it's not surprising as that's only 110uF at 230V.) All same Saturn/YC manufacturer.

I predict the next wave of Chinese PSUs will consist of a lead acid battery and a few voltage regulators.

**goodpsusearch** · 03-15-2012, 04:25 PM

Re: Power supply build quality pictorial. part 2

Originally posted by tom66 View Post

The 470uF primary caps by the way tested at 330uF on my ESR cap meter - both of them - w/ESR about 0.11 ohms. And if it wasn't enough of a coincidence, the 330uF primary caps in the "Lite" edition tested at 220uF 0.13 ohms each (those were in the PC with the 100 Hz ripple, so it's not surprising as that's only 110uF at 230V.) All same Saturn/YC manufacturer.

same:
https://www.badcaps.net/forum/showpo...&postcount=131

they cannot be trusted

**Th3_uN1Qu3** · 03-15-2012, 10:31 PM

Re: Power supply build quality pictorial. part 2

Originally posted by tom66 View Post

I predict the next wave of Chinese PSUs will consist of a lead acid battery and a few voltage regulators.

And with the charging circuit from cheap flashlights - that cap in series with the mains that loves to catch fire.

Announcement

Power supply build quality pictorial. part 2

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