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Reply 40 of 134, by wiretap

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The calculation is total. It is per IPC-2221 for trace current carrying capacity. It is a very conservative calculation with only a 10C degree rise above ambient. In reality it could easily do 2x as much current as I referenced.

I made this adapter since I didn't see any direct plug-to-board style adapters available for the P8/P9 AT connector. It gives a nice short adapter to plug a PicoPSU into so it isn't flopping around in the case hanging off a bundle of wires.

Again, it is an open source project, so feel free to rework it how you see fit.

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Reply 41 of 134, by wiretap

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Sphere478 wrote on 2022-02-22, 06:28:
Question, I see one pin on the atx is listed as nc. Is that the -5v? […]
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Question,
I see one pin on the atx is listed as nc.
Is that the -5v?

If so, you should be able to connect it to -5v and the regulator -5v it will only combine the two signals for more stable power.

The NC is where -5V would be on early ATX revisions. It doesn't need to be connected on the ATX plug since this adapter board generates its own -5V with the 7905 Linear Voltage Regulator. There's no concern about stability with that power feed. It is the same exact design I used here: Re: New solutions to the ATX -5V problem -- it has been tested and works awesome. 😀

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Reply 42 of 134, by wiretap

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Here you go.. high current variant. 5V and 12V planes are on the outer layers with no thermal reliefs. So from pin to pin, it is all solid copper. Being on external layers allows for better cooling under high amperage draw. It should be able to handle just about anything you throw at it in terms of retro hardware. But, it is going to require a high wattage soldering iron to be able to solder the 12V and 5V pins cleanly. Everything else still has thermal reliefs.

The intended application for this would be with a normal ATX power supply or HDPLEX power supply for late AT systems requiring more power.

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Reply 43 of 134, by Sphere478

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Sweet! Yeah, that’s gonna be quite the fun one to solder…. Flux paste will prob help transfer the heat.

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Reply 44 of 134, by imi

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are you sure these molex connectors would fit a standard AT motherboard connector?
according to the datasheet they seem to be for 1.4mm square pins, I'm not sure from just looking at it if they'd fit the blade type AT connector which seem to be quite a bit wider than that.

I've been trying to look myself for connectors for a PCB adapter like that before but I had never found any that would actually fit.

Reply 45 of 134, by wiretap

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I'll know for sure once the parts get here.. but half of my AT motherboards have the round or square pins, and half have the flat type. It is the same product series I replaced one of my corroded motherboard's AT power connector with. Supposedly it mates with it. (Molex KK-396 interconnect system)

Original AT power connector male part..

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The compatible female connector according to Molex, which I have in this design:

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Reply 46 of 134, by wiretap

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Update. These only fit the square pin variant. I don't know if I'll be able to find the legacy flat blade style in a 90-degree female board mount, but I'll continue the search.

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Reply 47 of 134, by wiretap

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Did some research.. It appears Molex only produced the flat style AT pin header for use with the 90331 connectors. Those flat pin 8619 style connectors were only used on AT motherboards to a certain time period, then Molex discontinued the 8619 and replaced it with the KK 396 square pin connector as seen on the motherboard above, which is compatible with the 90331 connector, as well as KK 396 female connectors obviously. So, the only way to do a board mount connector is to use the one I am using in this design. If the motherboard uses the old 8619 connector, it would need to be replaced with the KK 396 type. So, with the KK396 compatible with both the 90331 and KK396 itself, you lose no functionality with the original connector.

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Reply 48 of 134, by Sphere478

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You could always just use the normal wire style connectors and glue them to the board. And solder the wires in.

I see you ordered the prev version.

Was hopin to see the low profile version in action.

Lookin good though!!!

About time we had a better way to adapt these.

If the idea is to change out the connector, maybe we could just design a low profile direct solder atx plug interposer. Just remove the AT middle man.

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Reply 49 of 134, by wiretap

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Low profile version comes this week.

As far as glue, it probably wouldn't hold since it takes some extreme force to install/remove all 12 pins at once 🤣.

For a direct ATX to board interposer, that is a good idea and could be done. Since the AT plug is a standard pin spacing (3.96mm) there are a lot of options. It really sucks to desolder that connector though. Needs a lot of heat, and they usually tie all the 5V and GND in giant planes. My desoldering gun could barely do it.

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Reply 50 of 134, by Sphere478

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wiretap wrote on 2022-03-07, 20:30:

Low profile version comes this week.

As far as glue, it probably wouldn't hold since it takes some extreme force to install/remove all 12 pins at once 🤣.

For a direct ATX to board interposer, that is a good idea and could be done. Since the AT plug is a standard pin spacing (3.96mm) there are a lot of options. It really sucks to desolder that connector though. Needs a lot of heat, and they usually tie all the 5V and GND in giant planes. My desoldering gun could barely do it.

What about pulling the plastic off and soldering the at pins straight to pads on the adapter board?

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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 51 of 134, by wiretap

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You'd have to cut away the plastic, you couldn't pull it off since the mating side is wider than the board hole, but yea that route is an option too.

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Reply 52 of 134, by wiretap

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Reply 54 of 134, by Sphere478

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Heck yeah!!! That’s the stuff right there! Good job!

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 55 of 134, by bofh.fromhell

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Any reason you couldn't just plug a regular ATX PSU into this thing?
I mean this is much neater then the usual (mess of wires) converters we use.
Obviously you have to add a power on button, but that should be easy.
Possibly it could be added on these boards, jumper header and its done (?).

Anyways, brilliant stuff!

Reply 56 of 134, by Doornkaat

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bofh.fromhell wrote on 2022-03-18, 12:57:
Any reason you couldn't just plug a regular ATX PSU into this thing? I mean this is much neater then the usual (mess of wires) c […]
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Any reason you couldn't just plug a regular ATX PSU into this thing?
I mean this is much neater then the usual (mess of wires) converters we use.
Obviously you have to add a power on button, but that should be easy.
Possibly it could be added on these boards, jumper header and its done (?).

Anyways, brilliant stuff!

This was discussed on the first page. Wiretap adapted the PCB to have a jumper header that you can alternatively connect a switch to so now it'll work just like you propose (assuming you swap the momentary ATX switch for a latching switch).😃👍

Reply 57 of 134, by Sphere478

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Sure, should work fine with full size atx psus.

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 59 of 134, by Sphere478

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ajacocks wrote on 2022-03-28, 17:06:

I just ordered PCBs and parts to build 5 of these. I'll report back when I'm done.

- Alex

Ooo sweet!!!

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)