Delta Electronics GPS-350CN-100 need repair

[CapSwapper]

Re: Delta Electronics GPS-350CN-100 need repair

That's like saving a small piece of aluminum foil. Worthless! At least that's how it is for the cheap PSUs. Unless you save the components on the heatsinks too ("diodes-on-a-bracket" rectifier anyone? Oh Deer! )

The IEC power plug and rocker power switch (if there is one) are probably the most useful stuff for me. Followed by the primary and secondary HS silicone, fan, and many of the larger resistors (>1/2W). And wires sometimes...
So I just save the whole thing.

I am working on an oldschool HP lab DC power supply right now. The thing was dropped and had some parts smashed, including a 22 Ohm 1W resistor. But my junk PSU pile came to the rescue yet again! Found me a nice 22 Ohm 3W load resistor in one PSU. Also pulled some (crappy) caps to (temporarily) replace some of the 50 year old caps in that HP lab supply for a test to see if it works. I should be getting to that in a few days.

I save the heatsinks for electronic projects not to scrap them for cash. a lot of new psu's don't even have heat sinks on the rectifiers

[Behemot]

Re: Delta Electronics GPS-350CN-100 need repair

I save the heatsinks on PSUs too. I usually just put them in a case box and once I collect a box or two full of them, I take the box to the metal recyclers, and they will give you $50 or so.

Yeah just about that lol You have enough of them all the time if you really *need* some for whatever purpose…other than that you can just sell them for metal. I had tens of such crappy PSUs and I already had to disassemble them too at least for steel, aluminium, cables and transformers to save space.

[c_hegge]

Re: Delta Electronics GPS-350CN-100 need repair

Case box for what? A PSU? If you get $50 for that, then you all must be getting some really good prices for scrap down in Australia.
In my area here, you'll get that much only if you bring a half trunk full of copper. It's absolutely pointless to recycle anything for scrap here. Case in point: my friend had two large moving boxes full of Xbox 360 and PS3 heatsinks. He asked *several* local metal recyclers how much they'd give him for those boxes, and they said $10-$20. Not worth even hauling it to them! I gave him $5 for a smaller box he had (hence why I have Xbox 360 heatsinks on every computer ghetto mod of mine ).

I meant the cardboard boxes for an ATX case. I have one of those full of PSU, chipset and CPU heatsinks (only all-aluminum heatsinks. I keep and reuse the copper cored ones). I've just started filling up a second box with them. I'll take the two of them in once I fill it up, and I should get at least $50 for the two of them.

[goodpsusearch]

Re: Delta Electronics GPS-350CN-100 need repair

Thank you! I love Delta power supplies!

[TELVM]

Re: Delta Electronics GPS-350CN-100 need repair

... I assumed the single 3300uF capacitor for 12V without any pi coil would be insufficient in ripple suppression at high loads, so I moved some 12V cables to make space for a second capacitor for 12V. I used 2x2200uF instead of the single 3300uF capacitor ...

^ That's brilliant!

[momaka]

Re: Delta Electronics GPS-350CN-100 need repair

I save the heatsinks on PSUs too. I usually just put them in a case box and once I collect a box or two full of them, I take the box to the metal recyclers, and they will give you $50 or so.

Case box for what? A PSU? If you get $50 for that, then you all must be getting some really good prices for scrap down in Australia.
In my area here, you'll get that much only if you bring a half trunk full of copper. It's absolutely pointless to recycle anything for scrap here. Case in point: my friend had two large moving boxes full of Xbox 360 and PS3 heatsinks. He asked *several* local metal recyclers how much they'd give him for those boxes, and they said $10-$20. Not worth even hauling it to them! I gave him $5 for a smaller box he had (hence why I have Xbox 360 heatsinks on every computer ghetto mod of mine ).

[everell]

Re: Delta Electronics GPS-350CN-100 need repair

I yank out the heat sinks before tossing them. but thats about it.

There goes another Bestec ATX-250 12E. You learn SO MUCH by fixing one of them, but they are otherwise worthless.

[c_hegge]

Re: Delta Electronics GPS-350CN-100 need repair

I save the heatsinks on PSUs too. I usually just put them in a case box and once I collect a box or two full of them, I take the box to the metal recyclers, and they will give you $50 or so.

[momaka]

Re: Delta Electronics GPS-350CN-100 need repair

I yank out the heat sinks before tossing them. but thats about it.

That's like saving a small piece of aluminum foil. Worthless! At least that's how it is for the cheap PSUs. Unless you save the components on the heatsinks too ("diodes-on-a-bracket" rectifier anyone? Oh Deer! )

The IEC power plug and rocker power switch (if there is one) are probably the most useful stuff for me. Followed by the primary and secondary HS silicone, fan, and many of the larger resistors (>1/2W). And wires sometimes...
So I just save the whole thing.

I am working on an oldschool HP lab DC power supply right now. The thing was dropped and had some parts smashed, including a 22 Ohm 1W resistor. But my junk PSU pile came to the rescue yet again! Found me a nice 22 Ohm 3W load resistor in one PSU. Also pulled some (crappy) caps to (temporarily) replace some of the 50 year old caps in that HP lab supply for a test to see if it works. I should be getting to that in a few days.

[CapSwapper]

Re: Delta Electronics GPS-350CN-100 need repair

I yank out the heat sinks before tossing them. but thats about it.

[momaka]

Re: Delta Electronics GPS-350CN-100 need repair

^ But then you learn nothing .

Also, you'd be surprised how many useful components there are in even the crappiest of the crappiest PSUs. At the very least, you will get two 13007 or similar NPN BJTs, which can be pretty useful for many projects.

And you also get many other smaller transistors and resistors. Now that Radio Shack is gone, having a small stash of "junk" parts is even more useful if you need something ASAP.

[CapSwapper]

Re: Delta Electronics GPS-350CN-100 need repair

I see people enjoy repairing these old psu's but if I had it it would in a landfill

[goodpsusearch]

Re: Delta Electronics GPS-350CN-100 need repair

Nice fix! I have a few deltas that do the same thing. I will see if they have the same issue. Thanks for sharing!

Even when Delta makes a basic half bridge unit, they still do a really good job. I don't like that the 5VSB switcher is on its own heatsink though.

It doesn't overheat No discoloration on PCB too!

[Wester547]

Re: Delta Electronics GPS-350CN-100 need repair

Nice fix! I have a few deltas that do the same thing. I will see if they have the same issue. Thanks for sharing!

Even when Delta makes a basic half bridge unit, they still do a really good job. I don't like that the 5VSB switcher is on its own heatsink though.

That's not as bad as some other Newton or older Delta units where the +5VSB switcher has no heatsink at all. On the other hand, even without a heatsink, those FETs didn't get very hot, so Delta seem to know what they're doing for the most part.

[Pentium4]

Re: Delta Electronics GPS-350CN-100 need repair

Nice fix! I have a few deltas that do the same thing. I will see if they have the same issue. Thanks for sharing!

Even when Delta makes a basic half bridge unit, they still do a really good job. I don't like that the 5VSB switcher is on its own heatsink though.

[c_hegge]

Re: Delta Electronics GPS-350CN-100 need repair

Nice, although I don't think Koshin are any better than CapXon. I don't think I've ever seen a non-failed one that was more than a couple of years old, although for the fan, it probably doesn't matter that much if it fails, as fans don't usually care much even if they get subjected to a couple of volts of ripple.

For a Delta, though, it's definitely worth using only good Jap caps to repair it. It should just about last forever now.

[goodpsusearch]

Re: Delta Electronics GPS-350CN-100 need repair

This took a lot of time to repair/rebuild. I hope it's worth the time and effort!

Added an NTC thermistor.

Replaced the Capxon 680uF(real c: 620uF & 630uF) primary caps with Panasonic 800uF 200V 105C.

I Removed the glue around the thermistor and attached it at secondary heatsink with thermal compound for better thermal contact and used a plastic case from a dead Dell psu made by Huntkey.

I chose a Top Motor ball bearing fan from an exploded Antec Smart Power psu to put in place of the original that was missing when the psu was found. The ball bearing fan has a mb connector for RPM sensing.

I modded the fan controller because the psu was very loud without getting even warm. This was a quite challenging task.

I assumed the single 3300uF capacitor for 12V without any pi coil would be insufficient in ripple suppression at high loads, so I moved some 12V cables to make space for a second capacitor for 12V. I used 2x2200uF instead of the single 3300uF capacitor. I tried not to go too low esr and make the psu oscillate.

I recapped the psu using GOOD caps.

3.3V:
1xChemicon KY 2200uF 10V
1xChemicon LXZ 2200uF 16V
5V:
1xChemicon KY 2200uF 10V
1xChemicon LXZ 2200uF 16V
12V:
2xChemicon LXZ 2200uF 16V
5vsb:
1xChemicon LXZ 2200uF 16V
1x Rubycon YXG 1000uF 6.3V
-12V:
1xLtec LTG 470uF 16V (left alone)

Exception: Fan Capacitor
1x Capxon KM 47uF 25V--> Koshin 47uF (anything is better than Capxon! )

So, what do you think?

[Wester547]

Re: Delta Electronics GPS-350CN-100 need repair

Not necessarily. It all depends on the device what it is used for.

For example, at really high power applications, the devices will also tend to be very big. For MOSFETs, this usually means large gate capacitances, so that can become a limiting factor in how fast the device can be turned on.

Early in the days of semiconductors (think back to 74- TTL logic and earlier), BJTs used to be regarded as the faster switching devices. But that's because CMOS (MOSFET) technology had not yet fully developed. The problem with early MOSFETs was that they had rather sensitive gates (especially to static) and couldn't be turned ON/OFF very quickly, even if you could provide them with large enough gate currents. But FET technology has evolved much since then, and MOSFETs have caught up and surpassed BJTs in many aspects. However, BJTs are still tougher in general. That's because a BJT is essentially like two diodes on one die.

Diodes have been less tough than FETs, in my experience. And as far as I know, BJTs are very fast as linear switches, but as a saturated switch, their switching speed is slow compared to modern MOSFETs.

BJT's don't have an "ON" resistance. Instead, when fully saturated, they have a constant voltage drop between their C-E terminals, which is usually at least as high as the base-emitter voltage (so upwards of 0.6V). Therefore, the power dissipation of the BJT device increases almost linearly as the current though the BJT device increases (Pd = Vce * Ic).

That's why I said their "equivalent" of ON resistance. As I understand it, they do have some sort of "load" resistance during on and off switching times, though. And as far as I know, yes, BJTs have a negative temperature coefficient in that sense. AFAIK, MOSFETs are voltage driven and BJTs current driven as you correctly pointed out.

With MOSFETs, it's a difference story. The power dissipation of the FET depends on the Rds_on resistance and current going through the FET. Or:
Pd = Rds_on * Id^2. (Id = drain current)

And of course, the way the two devices function is completely different. BJTs act like current-controlled current source (push/pull a small current in the base of the BJT, and you get a large current out/in the emitter - all related by the current gain, hFE). With FETs, they are more similar to an electronic switch... or a voltage controlled resistor if you run them in their triode region.

Well, for MOSFETs, I would take into account ON resistance, gate resistance, load resistance, power dissipation, current rating, etc....

And I figured it was a bad rectifier or transistor (in this case transistor). Good work goodpsusearch.

[goodpsusearch]

Re: Delta Electronics GPS-350CN-100 need repair

Yep, that looks like the transistor for the 3.3V rail mag-amp circuit. Need to replace it. Considering the original is described as "low frequency power amplifier", that means you can use just about any PNP transistor. Just match the current rating and type (PNP). I really doubt you need a voltage rating as high as the original. And perhaps avoid transistors with a very low current gain (low hFE). On that note, the hFE doesn't need to match perfectly - just need to get it in the ballpark more or less. The transistors is used for switching here, so the hFE only needs to be large enough to enable the transistor to fully turn ON.
Something like TIP42 might work here (although, be advised that TIP42 is TO-220, so you might have to put it else where and run wires to it). Or B772. Just see what your local shops have, and let us know. It really just needs to be PNP type and TO-92MOD case or larger. I would go for TO-126 like the B772 transistor - it's smaller than TO-220, but larger than TO-92MOD. Or try SOT-223 if you want a ghetto-looking repair .


It does look a bit toasty. Make sure it is not touching the secondary heatsink or the other coil. Perhaps it was shorting on something. Or maybe someone just overloaded the 3.3V rail on this PSU. Who knows. Fix what's broken first and we can go from there. Maybe get two PNP transistors for the mag-amp, just in case .

I did that and now the psu works!

I used A1013, bought 3 just to be sure if the first blows, I will have more chances

The 2 mag amp coils were glued together. This is the good type of glue (well, I hate glue in psus, but that's another story) that doesn't get brown with age/heat. Still, I removed the glue and made sure the coils don't touch the heatsink and each other.

The psu works, but the voltage regulation with no load / DVD-Rom / Laptop HDD is disappointing. The psu I got is a stripped down version. There is no PPFC although the primary heatsink is designed to leave space for a PPFC coil. There is not daughterboard for second 12V rail support etc. This psu is a single rail unit.

I found a photo online of how this psu should be:
http://arch.pconline.com.cn/pingce/2...wer_359_07.jpg

Find the differences

[momaka]

Re: Delta Electronics GPS-350CN-100 need repair

Well, it was to my knowledge that BJTs generally have much slower switching speeds than MOSFETs.

Not necessarily. It all depends on the device what it is used for.

For example, at really high power applications, the devices will also tend to be very big. For MOSFETs, this usually means large gate capacitances, so that can become a limiting factor in how fast the device can be turned on.

Early in the days of semiconductors (think back to 74- TTL logic and earlier), BJTs used to be regarded as the faster switching devices. But that's because CMOS (MOSFET) technology had not yet fully developed. The problem with early MOSFETs was that they had rather sensitive gates (especially to static) and couldn't be turned ON/OFF very quickly, even if you could provide them with large enough gate currents. But FET technology has evolved much since then, and MOSFETs have caught up and surpassed BJTs in many aspects. However, BJTs are still tougher in general. That's because a BJT is essentially like two diodes on one die.

though it was also to my knowledge that plain old BJTs operate best at switching frequencies below 70KHz, and that their power dissipation was not as good as that of a MOSFET (though I think they might have an advantage as far as their equivalent of ON resistance goes).

BJT's don't have an "ON" resistance. Instead, when fully saturated, they have a constant voltage drop between their C-E terminals, which is usually at least as high as the base-emitter voltage (so upwards of 0.6V). Therefore, the power dissipation of the BJT device increases almost linearly as the current though the BJT device increases (Pd = Vce * Ic).

With MOSFETs, it's a difference story. The power dissipation of the FET depends on the Rds_on resistance and current going through the FET. Or:
Pd = Rds_on * Id^2. (Id = drain current)

And of course, the way the two devices function is completely different. BJTs act like current-controlled current source (push/pull a small current in the base of the BJT, and you get a large current out/in the emitter - all related by the current gain, hFE). With FETs, they are more similar to an electronic switch... or a voltage controlled resistor if you run them in their triode region.
---------------
Woops, sorry for double-posting. I thought I had integrated this into a single post.