VOGONS


New solutions to the ATX -5V problem

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Reply 21 of 60, by zapbuzz

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wiretap wrote on 2021-07-23, 18:47:
Tested and 100% working. […]
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Tested and 100% working.

Here's my -5V inline adapter assembled:
h3J2cRb.jpg

Installed in the ATX to AT adapter (wire colors of the chinesium cable aren't right):
KoGprfu.jpg

QpzdZRy.jpg

This is the one I say take my money! I have an old pc that needs one to live again!

Reply 22 of 60, by LeFlash

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wiretap wrote on 2021-07-05, 13:33:

You could supply an additional 5V/10A from the 12V output with a circuit like this (just erase the transformer/rectifier section:
It could be put on a small PCB, and you could also integrate the -12V to -5V circuit on it as well. Looks like it would be around $20-25 to build.

Using linear regulators for that kid of job is bad!
When you pull 5V/10A (50W) you have roughly 70Watt ( (12-5)*10) loss in the form of heat!
Better use a proper step-down-converter.
These can be bought cheap as working modules, so there is simply no need for doing it on your own.

Reply 23 of 60, by scorp

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Hi @ananananas, I somehow missed this and was just pointed out to this thread. Great work and a good alternative solution to the voltage blaster! I don't think, that this is cheaper, but I'm pretty sure, that many people will be glad to have something, what doesn't waste an ISA slot. I actually was working on something similar as well, but with additional circuitry for digital ATX switch. Unfortunately, I never finished it, just too many projects and too little time. And why do you think, that you need to ask anyone to sell it? Even if voltage blaster and your neat device are both solutions for the same problem, still you went a completely different way. I think, in the end it is nice to have both solutions and everyone can choose, what fits best in particular case. But just if you insist, I'm glad about your work and would be really happy, if people would support you buying this devices from you. I don't have anything against it and I'm pretty sure Phil thinks in the same way.

My Youtube channel Necroware

Reply 24 of 60, by Cyberdyne

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Usually -5 gets a 0,25A maximum current with all your retro -5V stuff 😁

Soooo a linear voltage converter works just fine!!!

I am aroused about any X86 motherboard that has full functional ISA slot. I think i have problem. Not really into that original (Turbo) XT,286,386 and CGA/EGA stuff. So just a DOS nut.

Reply 25 of 60, by pan069

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schlomoe99 wrote on 2021-03-03, 15:26:

This is pretty neat! I have one of those cable solutions from eBay with the in-line resistor but those are no longer available. This is much better and takes up less space!

You mean these? I bought a bunch of them a few years back. So far they have served me well. Unfortunately no longer available.

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Reply 26 of 60, by ananananas

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scorp wrote on 2021-08-04, 09:11:

Hi @ananananas, I somehow missed this and was just pointed out to this thread. Great work and a good alternative solution to the voltage blaster! I don't think, that this is cheaper, but I'm pretty sure, that many people will be glad to have something, what doesn't waste an ISA slot. I actually was working on something similar as well, but with additional circuitry for digital ATX switch. Unfortunately, I never finished it, just too many projects and too little time. And why do you think, that you need to ask anyone to sell it? Even if voltage blaster and your neat device are both solutions for the same problem, still you went a completely different way. I think, in the end it is nice to have both solutions and everyone can choose, what fits best in particular case. But just if you insist, I'm glad about your work and would be really happy, if people would support you buying this devices from you. I don't have anything against it and I'm pretty sure Phil thinks in the same way.

No I was talking about selling Voltage Blaster clones. With that I had an issue because what I had spun was 100% copy-paste but SMD basically. So I received a go-ahead from the guys and I think I still have one or two left. But since the eBay fees and everything else that goes to selling anything quickly raise the price, it's been more or less hobby to send them out.

But my own design, now that you mention, has ATX style momentary switch support. Lack of which was pointed out on this thread and whilst I initially dismissed the idea, I later realized that it's a must. Also, I added a push-button, which has become a staple at the bench and couldn't live without it.

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Reply 27 of 60, by BitWrangler

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Cyberdyne wrote on 2021-08-04, 10:50:

Usually -5 gets a 0,25A maximum current with all your retro -5V stuff 😁

Soooo a linear voltage converter works just fine!!!

Yeah good point only needs to lose a handful of watts, so, seeing the value 20 ohms on this...

pan069 wrote on 2021-08-04, 11:30:
schlomoe99 wrote on 2021-03-03, 15:26:

This is pretty neat! I have one of those cable solutions from eBay with the in-line resistor but those are no longer available. This is much better and takes up less space!

You mean these? I bought a bunch of them a few years back. So far they have served me well. Unfortunately no longer available.

PXL_20201001_061307745.jpg

I might just stick a five watt or bundle of 1 or 2 watts whatever I scratch up, if I find myself in dire need of -5 in a hurry... though I think I have actual linear regs around somewhere for the first or second instances, that probably ain't so hard to tag to 3 lines of stripboard and use. Though if I had them kicking around I might chain 10 or 11 diodes too.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 28 of 60, by scorp

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ananananas wrote on 2021-08-06, 15:37:

No I was talking about selling Voltage Blaster clones. With that I had an issue because what I had spun was 100% copy-paste but SMD basically. So I received a go-ahead from the guys ...

Hehe, just to exclude any misunderstanding, Necroware is my YT channel 😉

My Youtube channel Necroware

Reply 29 of 60, by ananananas

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scorp wrote on 2021-08-06, 16:09:
ananananas wrote on 2021-08-06, 15:37:

No I was talking about selling Voltage Blaster clones. With that I had an issue because what I had spun was 100% copy-paste but SMD basically. So I received a go-ahead from the guys ...

Hehe, just to exclude any misunderstanding, Necroware is my YT channel 😉

Sorry, didn't realize. Yeah, but since it was copy with literally no other modifications but change of the regulator part, wanted to know if it was OK for you. And brand names are always tricky. So it's best to avoid those. Although the license you now share it under it pretty permissive.

Reply 30 of 60, by scorp

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As I told, I have no problem at all, if you want to sell it. I'm even glad, that people find it helpful. If you ask for my opinion, I always appreciate, if people leave the original names of the developers and contributors (if there are not too many) on the PCB. It's a great way to say thank you, but it's up to everyone's decision. I do all of my projects open source and people are free to do with it whatever they want.

My Youtube channel Necroware

Reply 31 of 60, by Gonduron

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It's a few months back since the last post in this thread, so I hesitate to post here. Yet, this is an evergreen topic, and I like it when I find all related information in one place. By this post I just want to provide to fellow PC-builders some info that I have been looking for while planning my 486DX4 retro-PC.

Intro
Old AT PSUs are more and more difficult to aquire. Even when you find an old AT PSU, the aged caps inside at some point will die of old age. This is inevitable. Low quality soldering points get rusty and accumulated dust and dirt can results in shorts. Even circuit boards can show signs of bad age and fail. When any of this happens, you've got good chances that the AT PSU fries your rare stuff.

Better ATX then AT PSU
If you know how to verify the old caps inside and resolder them, ok. But if you don't, then a new ATX PSU made by an established PSU-manufacturer such as Seasonic is definitely the better option. Even though I'm familiar with electrical engineering, I would rather choose the ATX alternative.

The -5V rail problem
However, the missing -5V rail on new ATX PSUs is a problem for all systems with AT motherboards (most 486). I understand that many systems do not utilise the -5V rail. But when you do not know whether any of your ISA cards or motherboard components needs the -5V, it always safer to provide it then to bet on chances. Tinkering and testing is part of our hobby, but you should not apply this to PSUs, because here the general rule is better safe then sorry.

PSU requirements
I was lucky to get hands on two different AT PSUs: a Task TK-920VZ and two Fortron/FSP SPI-300G(PF), two typcial AT PSUs at the 486DX4 age. Both provide max. 0,5A at the -5V rail, and max. 0,5A at the -12V rail. When you have no clue what the exact requirements of your systems are, these stats of those old PSUs are a safe guideline of what you should provide to your AT mainboard. Should you use a voltage converter that draws on the -12V rail, be aware that this will reduce the amps leftover for your motherboard.

Selecting an ATX PSU model
The vast majority of the current ATX PSUs provide only 0,3A at the -12V rail. Now if you use that rail to generate the -5V, this means you're providing just about the half of the amps of what old AT PSUs provided back then. Since all -5V converters that I have spotted so far draw on the -12V rail, this could be a criteria which ATX PSU to buy. Some mid and high-end PSUs provide 0,5A and very few models even 0,8A on the -12V rail. Chances are that even only 0,3A at the -12V rail will still work for most systems, yet - following the better safe than sorry doctrine - I would rather go for 0,8A on the -12V rail.

However, general PSU quality (pay attention to MTBF or manufacturer warranty) and amps on the -12V rail are not the only criteria to pay attention to. An old 486 needs only a small percentage of the vast Wattage modern ATX PSUs supply. If you're eco-friendly or just do not want to generate more heat inside of your PSU than all of your components together, the "80 Plus Titanium" badge is a must-have as it is the only one with a min spec for 10% loads. Also you may want to go for the lowest wattage available in the series. Even the lower end 500W PSUs provide more than double of what you need.

Feel welcome to correct me or add anything critical that I have forgot.

My "Pixeli": Intel 486DX4-100 -- Asus VL/I-486SV2GX4 -- 16 MB -- Diamond Stealth64 S3 Vision868 2 MB VLB -- AWE64 Gold -- Roland LAPC-I and SCC-1 -- Adaptec AVA-2825 -- IBM 1 GB SCSI-2 -- Plextor 8x -- Teac 3,5" + 5,25" -- EIZO S2133

Reply 32 of 60, by Thermalwrong

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An 80plus titanium PSU seems like overkill?

btw I use this -5v regular module in my projects and it happily runs off the 3.3v rail, providing +5 (unused) and -5 volts. It's working nicely on my ISA SBC riser - those each use PicoPSUs since none of them (386, 486, PentiumMMX) need much power.

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Reply 33 of 60, by debs3759

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I've been reorganising my collection lately (long way to go yet) and found most of my AT cases have PSUs in them, and I have extra AT PSUs as well as a few ATX with -5V. Going to recap them all, to be on the safe side.

See my graphics card database at www.gpuzoo.com
Constantly being worked on. Feel free to message me with any corrections or details of cards you would like me to research and add.

Reply 34 of 60, by Sphere478

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wiretap wrote on 2021-05-19, 21:08:
Here's another I just made.. you would just cut the ATX-to-AT adapter and solder this inline. Top is input from the ATX side, bo […]
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Here's another I just made.. you would just cut the ATX-to-AT adapter and solder this inline. Top is input from the ATX side, bottom is output to the AT side. Then just put some heat shrink over the whole thing.

Mouser Cart: https://www.mouser.com/ProjectManager/Project … ssID=72e7534197
Gerbers and KiCAD is attached.

Tested, working design. Assemed on July 23rd, 2021.

mYAsOhH.jpg EX070Nh.jpg

That’s brilliant.

Wonder if maybe it could be made to use some sort of alternate attachment method for the wires though like spade terminals. Or little green lugs

I hate having soldered in wires in a application that gets moved often, and lets face it, we are always digging in our retro rigs.

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Reply 35 of 60, by Sphere478

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ananananas wrote on 2021-02-21, 12:41:
ATX2AT I think was the first solution to address the issue. But it was a very limited run. And I saw one problem with it, beside […]
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ATX2AT I think was the first solution to address the issue. But it was a very limited run. And I saw one problem with it, besides its price: it used a custom-built cable. I saw that as a problem. I didn't like the idea.

So I decided to try and address the issue. And I produced a clone of it. But it was little bit too much to bite so I chose another project which is this one right here. A simple in-line adapter to adapt a 24-pin ATX power connector to AT power connectors. Which lets me use modern ATX power supply with OVP, OCP and short circuit protection, but also adds the missing -5V.

Recently Phil's Computer Lab and Necroware released their own ISA card version, which is very clever and simple. I was impressed. Even envious of such clean design. But some commented they would rather have an in-line solution. One is cheaper, one does not take an ISA slot.

If I can improve this design, what should I add, include or change? Have you seen something else yourself? Please, comment. I have spent enough time on this to not release it. It is of no use if left unreleased. Input is welcomed.

And a final note: I have a bunch of these and I must somehow deal with them. If anyone wants to buy one, post me a message send me an email ananananas@gmx.us. I also have bunch of the ISA card versions assembled but I would like to get a comment from Phil or Necroware before I wish to sell those. I don't feel right selling them. Maybe I can release the Eagle files and if you guys want to take advantage of those and make available an assembled version, perhaps that would be a solution? Because if I could order a bunch of 30 of those since you guys released them, I see there is even more benefit to the community to let these be even more easily available. What do you think?

I have an idea

Basically everyone who owns a asus p5a knows how limited they are with cpu heatsinks but it just might be possible to make a little more room by modifying your idea with a low profile plug and some pcb trickery.

The latch is oposite of the socket and there isn’t much room around it in your typical case but perhaps a vertical installation and some shaving of the plastic on the plug and maybe a golden orb might just fit?! And give me -5v!!

Thoughts?

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 36 of 60, by cyclone3d

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Ewww... a golden orb. Those things are trash as far as cooling goes.

I worked at a computer store when those were all the rage.... poor saps who bought them.

They had them in different configurations.. even had a super tall one with two fans in it.... uggghhhh.

Fins are too thick to actually dissipate heat properly (not near enough surface area) and so once the hunk of metal becomes heat saturated it is game over.

The $10 crappy style finned heatsinks cooled better than those pieces of trash.

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Reply 37 of 60, by Sphere478

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cyclone3d wrote on 2021-12-30, 04:41:
Ewww... a golden orb. Those things are trash as far as cooling goes. […]
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Ewww... a golden orb. Those things are trash as far as cooling goes.

I worked at a computer store when those were all the rage.... poor saps who bought them.

They had them in different configurations.. even had a super tall one with two fans in it.... uggghhhh.

Fins are too thick to actually dissipate heat properly (not near enough surface area) and so once the hunk of metal becomes heat saturated it is game over.

The $10 crappy style finned heatsinks cooled better than those pieces of trash.

🤔

I have a nice copper p3 one but no chance of it ever fitting.

I’m stuck with this little 1/2” tall blue one with a fan on top. It looks so tiny 🤣.

I have some nice passive ones but ugh, they don’t fit well. Except this little tiny one that I have that may actually be a north. Bridge cooler 🤣

So basically there isn’t much heat to tame but the orb is the coolest one I got that might fit.

This one is silver orb🤗

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
-
Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 38 of 60, by cyclone3d

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I have one f the silver orbs. Came in a lot of other stuff if I remember correctly. I wouldn't ever use it except for a quick test.

The motherboard I had back then was a P5a. Sure you can't fit a giant cooler on there but I had no problems getting one that fit.

Probably one of the best from that era was the Antec thin finned one.

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This particular cooler is the one I have been using when testing stuff with an ASUS P5A-B.

The biggest problem is the placement of the CPU socket on that board as an AGP card barely clears the heatsink. So much so that I put electrical tape on the side of the cooler to keep it from shorting anything on the back of the card.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 39 of 60, by wiretap

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Sphere478 wrote on 2021-12-30, 01:01:
That’s brilliant. […]
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wiretap wrote on 2021-05-19, 21:08:
Here's another I just made.. you would just cut the ATX-to-AT adapter and solder this inline. Top is input from the ATX side, bo […]
Show full quote

Here's another I just made.. you would just cut the ATX-to-AT adapter and solder this inline. Top is input from the ATX side, bottom is output to the AT side. Then just put some heat shrink over the whole thing.

Mouser Cart: https://www.mouser.com/ProjectManager/Project … ssID=72e7534197
Gerbers and KiCAD is attached.

Tested, working design. Assemed on July 23rd, 2021.

mYAsOhH.jpg EX070Nh.jpg

That’s brilliant.

Wonder if maybe it could be made to use some sort of alternate attachment method for the wires though like spade terminals. Or little green lugs

I hate having soldered in wires in a application that gets moved often, and lets face it, we are always digging in our retro rigs.

Yes, you could design it to have ferrules on the cable ends with weidmuller blocks on the board. But I wouldn't call it much more reliable. Solder with heatshrink over it is plenty to keep it from bending/breaking. When you remove a connector, you don't pull by the cables, you pull from the connector.

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