Re: What does your significant other think of your retro pc hobby?

Posted on Today, 13:29

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

RetroPCCupboard, why don't you tell her you've decided to change your hobby and you're going to sell all your old computer stuff to buy a sports bike? Then your wife will either beg you to stay with the old computers or will go into hysterics mode 🤣

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-14, 16:21

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

One other thing that came to my mind regarding the diodes (without having really thought about it yet): Could it also be a possible solution instead of increasing the drop over the 12V diodes to decrease the drop over the 5V diodes? That way the 5V should come out higher while the 12V could be …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-14, 11:55

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Horun wrote on 2025-01-14, 03:04: I too think is a wise choice and should work better/easier than series diodes. Thanks for your approval on my not-so-wise second idea 😉 I'll do this as the easiest option in my case, as I don't have any suitable spare output inductor replacement.

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-14, 11:31

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

momaka , kudos for all the info on the inductor ferrite core materials! It's always a pleasure to learn something new from someone with knowledge and practical experience. Looking at the first one and the last one of these, I see they show pin 16 ("+12V" / "OVP+12V") is indeed connected to the 12V …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-13, 16:19

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

OK, got it. So first task is getting a new ferrite core as I don't have any parts like that in my parts bins. I'll try to have look into that asap and report back. Yeah, you can find some suitable inductor replacement from another PSU, this is the easiest solution. Or if you can't find any spare …

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Re: K6INIT: AMD K6-3/3+/2(CXT) initialization driver for MS-DOS

Posted on 2025-01-13, 15:46

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

PC@LIVE , there's no such thing as x 6.5 multiplier on (s)s.7 platforms. I'm not sure if K6 family CPUs officially support x 6 multiplier (as they use x 2 multiplier motherboard's settings for it). K6-2 at 433 MHz (427.5 MHz ??) seems like weird thing, but can be achieved on some ss.7 chipsets …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-13, 10:48

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

ChrisK , in short - the root of the voltage troubles with these particular FSP PNF power supply models (also applies to PNR models) is the bad material used for ferrite core of the output inductor, as seen (heard) from the explanations in the YT-videos, which I found some time ago and posted in one …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-13, 10:41

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

momaka , thank you very much for your detailed answer and all the explanations and practical tips! I can't find any datasheet for FSP3528 PWM controller and protection chip, but I found this web page (sorry, it's russian and you'll have to use some online translator). The other resources about …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-12, 19:40

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looking through some double diodes datasheets I found this one for SF160xG. Filename SF160xG.jpg File size 98.07 KiB Views 269 views File license Fair use/fair dealing exception I also found SF1608G diodes on chinese fleabay for dirt cheap, so I'll just change the two SF1603G (Vf ~ 1.0 V at 8.0 A) …

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Re: Patches and updates for games

Posted on 2025-01-11, 11:59

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by analog_programmer

in Marvin \ Software

in Marvin \ Software

I don't understand why this System shock 2 patch v. 2.03 is so precious, if there's available newer v. 2.23, but maybe someone have to dig into the well known software archive site - there are some old CD images with game patches.

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-08, 21:22

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yes think those should work well. Great! My last concern is their operating temperature and cooling, since I can't attach any heatsinks to them and they will only be cooled by the airflow from the PSU's fan. On the other hand these diodes will not actually work in rectifying mode. I just don't have …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-08, 20:52

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Something like two of these 25A max types (with Vf of .7 @1A, .8v @10A and axial leads): https://www.digikey.com/en/products/detail/diotec-semiconductor/P2500A/22191581 I can't find any similar in size and current rate of 25 A (or more) like these P2500A at my nearest local electronic parts shop, …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-08, 19:35

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Your idea of simple high current diode is probably the easiest. You could use 2 lower amperage in parallel to get higher max Amps. Something like two of these 25A max types (with Vf of .7 @1A, .8v @10A and axial leads): https://www.digikey.com/en/products/detail/diotec-semiconductor/P2500A/22191581 …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-08, 17:22

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Horun , now I've figured out the idea with the power double diodes measurements. It really makes sense if the V-drop of the double diode BD3 on the +5 V line has increased over time. On the other hand, there is no reason for the voltage on the +12 V line to increase with time due to similar aging …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-08, 11:30

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I see that here I'll not be able to find some electronic's way to reduce +12 V line output voltage slightly under 12 V, so both problematic +5 and +12 V lines voltage values can be adjusted close to their nominal values by VR1. Ok, let's try the electrician's way :) Maybe not the smartest idea, but …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-07, 09:22

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Agree should check the diodes. Also do you have a oscilloscope ? Am wondering what the ripple on the +5v line is compared to the +12v line under small load, might help pinpoint something. In a pinch can use a good digi voltmeter on ac (depending the dvm, some do not read well above a few hundred …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-06, 19:08

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Here it is the video with the solution, that did not help in my case 🙁 P.S. And this is the first video with the explanation of the off- +5 and +12 voltages problem for the same PSU.

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-06, 19:06

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

and also removing 1-2 windings from the +12 V winding with the increased output voltage. I did all of this, but for my PSU it did not give any noticeable result with improvement in the output voltage values in the problematic +5 and +12 V lines. I guess you are talking about L1 in the schematic. …

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Re: Need help for PSU Fortron/FSP ATX-350PNF with problematic +5 and +12 V output voltages

Posted on 2025-01-06, 12:21

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by analog_programmer

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I haven't touched the VR2 trimmer, which is on the main PCB, because I have no idea how it will affect the +12 V, possibly the +3,3 V (this voltage at least is stable - about 3,35 V and not affected by VR1 on the small PWM PCB) and +5 V voltages. Well, maybe I have to try fiddling with VR2 before …

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Re: Exploring the performance of S3d (S3 ViRGE)

Posted on 2025-01-05, 21:14

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by analog_programmer

in Marvin \ Video

in Marvin \ Video

Nice! The screenshot reminds me of the first room in TR1's "Tomb of Qualopec" level :) I know it, 'couse TR1 game is my "universal DOS test" for S3, 3dfx, Rendition and Matrox (unfortunately I can't get any PowerVR PCX1 or PCX2 cards) first (sometimes second) generation of 3D videocards and their …

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