Jump to content
IGNORED

Building an Unregulated Linear Power Supply


elan120

Recommended Posts

the EPS counts guys,,

 

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment

The victory was short lived. Apparently the rectifier get really hot when it’s doing it’s thing and I had mine resting on the jacket of the capacitor. Well then it stated melting the jacket of the capacitor and when I went to lift the rectifier off the capacitor jacket, one of the chips stayed stuck to the jacket. 
 

It’s kind of hard to photograph but it’s the shiny item in the green circle. 
62387A5B-D1FB-4733-B4E8-EE7D052C1DD0.thumb.jpeg.a62d9bbd02eb07653e0a7e155edcf641.jpeg45E99D60-7C36-46FF-ABCB-A9F7D5641FB5.thumb.jpeg.bbb6464bd32458864a77cc8e387949c0.jpeg
 

There was room to gap the two pieces I just didn’t think about doing so because I didn’t anticipate it getting so hot. Hopefully this knowledge helps someone else in the future. 
 

I’m going to have to dissemble and see if the chip can be resoldered or order a new rectifier. 

 

Link to comment

Well the only other thing that comes to mind are the jacketed wires feeding the ATX were close to the traces but I don’t think that could be it. The jackets are intact and no sign of shorting through the jacket. 

56D196ED-271C-40F3-9A59-E1BAEC37DF13.thumb.jpeg.c42eab83466d930f4f29aca237033d7f.jpeg

 

Maybe the neoprene wasn’t enough of an insulator from the case? EDIT: there was a 1/2 to 3/4” gap between between the rectifier and the neoprene. The neoprene is 1/8” thick. 30v won’t jump that large of a gap both ways and go through the neoprene.

 

35E9B5CD-E691-43E8-8B82-9A9F87CFB405.thumb.jpeg.bad4af6b6fe8754640bc0dfa9c1c068c.jpeg

 

Link to comment

There are conditions where you will be drawing more than 5A with the 19-12900K, even during boot. If you happen to saturate the chokes long enough their temperature will rise. The choke lead may be getting warm and conducting heat back to the cap terminal and rectifier lead. With the components face down  as you have them especially if touching the cap, their air cooling is impaired.

I would use an 8A or 10A choke. Saturation drops the inductance and distorts the ripple as well, l introducing additional unwanted harmonics. 

Just a thought.

ATB.

b.

Link to comment

although the choke may well be saturated at times, yet for the heat to travel up the lead to the cap and then heat the rectifies seems pretty impossible to me or you'd see the cable and or cap meltdown first.

Using a larger choke is a good suggestion anyhow

 

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment

Oke I found it.

They say that there wil be 3mv over the mosfet with 1A that's for 4 mosfets 0,012W

Let's say for 10A 30mv then you have for 4 mosfets 1,2W

So you have a problem why the pcb is getting so hot that the mosfet comes off the pcb.

Maybe a mosfet is gone or the 4320 ic, static electricity is a big enemy.

 

Rob 

Link to comment
3 hours ago, Exocer said:

What larger choke are people suggesting these days?

I'm using two Lundahls LL2773 in CMR but used in parallel it can handle 10A, the cores will not saturate anywhere near where the Hammonds will as they are a lot larger.

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment
Just now, oneguy said:

Keep in mind you will need 220,000uF of capacitance after the chokes per @Nenon’s post on Sep 14, 2021 in the DIY Music Server thread if you go with a 10A choke. 

Yes. Absolutely aware of this. We have spoken privately about the importance of increasing capacitance to accompany the larger choke. Glad you are bringing awareness to it 😎. With the Z390 platform, this test is way down on my list of experimentation items for now but I do already have some caps on the way to fill the need ;)

Link to comment

Yep, mainly just bringing that info back up on everyone’s radar so they know additional requirements come with a larger choke. Not specifically directed at you.

 

Some may not have the space. In my case I’ll have have to rethink my layout because larger chokes and 2 more caps will dominate the space I have left. 

 

Link to comment
12 minutes ago, oneguy said:

 

 have Hammond 195J10’s onhand which can handle 10A on hand. If the 159ZJ10 proved unworthy I was going to swap them in. Keep in mind you will need 220,000uF of capacitance after the chokes per @Nenon’s post on Sep 14, 2021 in the DIY Music Server thread if you go with a 10A choke. 
 

 

Which post exactly? I just looked back and did not find it on Sep 14?

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment
2 hours ago, elan120 said:

As a reference point, I just did a test to take some readings, and the initial bootup on my i9-12900K maximum power draw is 124.7W / 30.04V / 4.14A.  After bootup, in Bios menu, power draw is 69.4W / 31.84V / 2.18A.  This test ran with CPU at 4.9GHz, and using a 4A fuse on the power supply.  Note, the voltage output with no load is 35.4V.

Makes sense. My voltage output is 87% of yours so extrapolating that information possibly the 3 songs at upsample may have saturated the chokes but the 8-10 hours at idle prior to that wouldn’t. 
 

I’ll be using 100v/50hz wall power up until Nov then I’ll permanently be back on US spec power so if that 13% ends up being the margin that I need to prevent saturation I’ll finish the build here and table the ULPS until I move. 

 

Link to comment

Aftermath: 2 chips removed and 1 displaced. F7068C1C-CD16-40FC-A7B9-2E9312DF2E21.thumb.jpeg.22a951b196150847cb3639a489b0a66e.jpegF45EAB79-EA0F-428E-9603-106F1A9A6FDF.thumb.jpeg.8333ea8502db72ace7aaae5d5cec7a07.jpeg
As you can see from the underside of the chip (they are all the same part number) there is one large pad connecting 4 of the pins and and the other 4 pins connect to their own individual pads. 
 

There was enough solder present to reflow one of the them back but I need to get some solder paste for the other 2. 
AADBCDEB-F44D-4E39-92C4-8E40542369DF.thumb.jpeg.fbc462fd6476891c49e760c9b73d1ccd.jpeg

 

 

 

Link to comment
On 5/15/2022 at 3:29 AM, oneguy said:

Aftermath: 2 chips removed and 1 displaced. F7068C1C-CD16-40FC-A7B9-2E9312DF2E21.thumb.jpeg.22a951b196150847cb3639a489b0a66e.jpegF45EAB79-EA0F-428E-9603-106F1A9A6FDF.thumb.jpeg.8333ea8502db72ace7aaae5d5cec7a07.jpeg
As you can see from the underside of the chip (they are all the same part number) there is one large pad connecting 4 of the pins and and the other 4 pins connect to their own individual pads. 
 

There was enough solder present to reflow one of the them back but I need to get some solder paste for the other 2. 
AADBCDEB-F44D-4E39-92C4-8E40542369DF.thumb.jpeg.fbc462fd6476891c49e760c9b73d1ccd.jpeg

 

 

 

did you check the rest of your LPSU for shorts ? measure the first choke?

I can only imagine there is a short or similar making the current draw very high, but that active rectifier should be able to withstand currents that would leave your transformer real hot....weird? Did you contact the maker of the Saligny rectifier? What voltage do you measure after your transformer?

 

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment
2 hours ago, MarcelNL said:

 

did you check the rest of your LPSU for shorts ? measure the first choke?

I can only imagine there is a short or similar making the current draw very high, but that active rectifier should be able to withstand currents that would leave your transformer real hot....weird? Did you contact the maker of the Saligny rectifier? What voltage do you measure after your transformer?

 

I went through and checked and nothing is bridging the positive to negative terminals after the rectifier except the VCaps and the intended wiring. Nothing is bridged to ground except the IEC and transformer static shield. Besides above where the rectifier was, I don’t see any signed of excess heating of the neoprene insulator on the case lid. No part touches the lid and to arc through the neoprene would require a burns mark I would imagine.

 

Two of the VCaps are close to terminals but they are surrounded by a plastic insulator and there are no burn marks from arcing. All VCaps measure as an open load so no short there. 

 

I actually popped the cover off to specifically check the transformer temp. It wasn’t that warm. That’s when I discovered a plastic melting smell and let me know something wasn’t right. The server was operating properly. 
 

I had a 4A fuse installed in the output from the IEC and it didn’t blow so no more than 420w could have been flowing. The rectifier is rated for “continuous load current up to 20A or more depending on mosfet configuration.” Assuming there wasn’t a short the Taiko input voltage would have had to sag from 31V to 21V and the server would need to be demanding 420w. Not likely based on what I had powering it before. 
 

Did I miss anything? I’m still stumped.

 

Underneath the thin heat shrink boot around the capacitor there is a metal rim. Maybe the heat shrink got hot and thinned out? But what would have caused the heat shrink to get that hot in the first place?

 

Link to comment
19 minutes ago, oneguy said:

I went through and checked and nothing is bridging the positive to negative terminals after the rectifier except the VCaps and the intended wiring. Nothing is bridged to ground except the IEC and transformer static shield. Besides above where the rectifier was, I don’t see any signed of excess heating of the neoprene insulator on the case lid. No part touches the lid and to arc through the neoprene would require a burns mark I would imagine.

 

Two of the VCaps are close to terminals but they are surrounded by a plastic insulator and there are no burn marks from arcing. All VCaps measure as an open load so no short there. 

 

I actually popped the cover off to specifically check the transformer temp. It wasn’t that warm. That’s when I discovered a plastic melting smell and let me know something wasn’t right. The server was operating properly. 
 

I had a 4A fuse installed in the output from the IEC and it didn’t blow so no more than 420w could have been flowing. The rectifier is rated for “continuous load current up to 20A or more depending on mosfet configuration.” Assuming there wasn’t a short the Taiko input voltage would have had to sag from 31V to 21V and the server would need to be demanding 420w. Not likely based on what I had powering it before. 
 

Did I miss anything? I’m still stumped.

 

Underneath the thin heat shrink boot around the capacitor there is a metal rim. Maybe the heat shrink got hot and thinned out? But what would have caused the heat shrink to get that hot in the first place?

 

I think you got it covered, to me the metal case of the cap is unlikely a cause but who knows see if there is continuity between one of the cap connectors and its case) OR the rectifyer failing in some mysterious way...

 

On the Mundorf HC I have lying around the negative pole appears to be connected to the case, only thing I can come up with is that there may have been something connecting between the rectifyer and the cap case causing local overheating (which it was from the looks of your pictures) but who knows...

ISP, glass to Fritz!box 5530, another Fritz!box 5530 for audio only in bridged mode on LPS, cat8.1, Zyxel switch on LPS, Finisar <1475BTL>Solarflare X2522-25G, external wifi AP, AMD 9 16 core, passive cooling ,Aorus Master x570, LPSU with Taiko ATX, 8Gb Apacer RAM, femto SSD on LPS, Pink Faun I2S ultra OCXO on akiko LPS, home grown RJ45 I2S cable, Metrum Adagio DAC3, RCA 70-A and Miyaima Zero for mono, G2 PL519 tube amps. 

Link to comment
6 minutes ago, MarcelNL said:

 

I think you got it covered, to me the metal case of the cap is unlikely a cause but who knows see if there is continuity between one of the cap connectors and its case) OR the rectifyer failing in some mysterious way...

 

On the Mundorf HC I have lying around the negative pole appears to be connected to the case, only thing I can come up with is that there may have been something connecting between the rectifyer and the cap case causing local overheating (which it was from the looks of your pictures) but who knows...

All VCap leads and cases show as open loads. 
 

Maybe an unnoticed pin hole in the cap heatshrink got to the party started then from there it cascaded? My mind is still boggled. I am going to put a layer of silicone conformal coating on the cap in the spot where the case is exposed then a bit of electrical tape on top of that when it dries. 

 

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...