Hehe, now, there's a challenge!

Well, these things were a silly pseudo-feature to begin with, so they weren't exactly subject to a strict DIN standard 😉

But, as far as I can remember, they have

- fixed 5 V supply, hence the Molex adapter.
- Some way to tell them when Turbo is on or off.

Now, with a certain case I used to tinker with before the last three wars, the only second connection was to "Turbo Led" header on the motherboard.
So, instead of lighting a LED, it was telling the display to switch from one preset mode ("20" MHz) to the other (the actual 40 MHz of the Am386...).
Which was fun because you could attach it to the "HDD active" LED connector and have a large, bright, annoyingly flickering display.

Now, that is not your type of display.

That one seems to attach the button and pass that signal on to the mobo, right? At least that's what I take from btn_back if that black yellow cable is the original state.

So, to be borderline constructive, ideas for less foolish try-and-error:

I see several parts designated "+ and -"
This being a logical universe, attaching 5 V to any of these could not hurt.

If in doubt or as a last resort: There seem to be several markings on the PCB, yet covered by componenents, plugs, that resistor.
You could take a soldering iron and do some exploratory surgery to discover those markings.

Also, the one right place for the fixed power supply should induce that thing to light up.

That turbo button is usually closing the curcuit for the "turbo on" mode. You can check it, if the button is in the depressed or rear position, the wires should be shortened.
So, without those attached at all, the display should show whatever the previous system deemed the "low" state.
So, "lo", 33, 20, 16 or any number lower than the actual cpu frequency - if still known...

Then, where does that turbo button go?

The place for the turbo LED should not have current, Turbo being off. So, I assume you have a voltmeter.
If only one place has 5 V in that state, chances are, that's the place for the button.
Merely a hypothesis, so shorten that at your own risk. If I'm right, it would switch the display.

One more idea: IIRC, those AT front panel connectors DID have some order to them.
One of those being, one of the cables was 3 wires instead of 2.
Think, that was the turbo switch, maybe because the switch would go from 1-2 to 2-3 because motherboards couldn't quite make up their mind whether "open" meant "turbo on" or off, but the depressed button was always supposed to be the "on" state, so you could chose how to tell the mobo.
That in case you can figure out where the 3 button cable goes.

But, as I can see, that yellow-black cable seems to be the turbo button.
I checked both AT cases with displays I have here, bot adhere to the color scheme in the picture, should be white, black, orange.

Sorry, your case is weird. Next time, take a phote before disassembly, will you?

Fingers crossed that the crowd will come up with a definitive answer!

oh, and that PSU: Duh, there's a Netzschalter on it, how about that?

Actually, those white, blue, black, grey cables in the back used to be attached to it, in the front panel.
So, two of them come from the mains, two need to be connected via the switch to power the PSU.
No, I'd have an educated guess as to which is which but I'm not going to bet on it - if I'm wrong, you'll have to open a window.
Please google on your own for the color scheme.

Simple way to find out:
- attach a power cord to the PSU and a mains plug.
- test with a phase checker screwdriver which one of the for has 230 volts now, preferably without touching them
- rotate the Schukostecker by 180 degrees
- check again which of the other three has juice now
- remember the two
- attach those two to one side of the switch, and the other two to the other side, thus connection the two pairs with each other - one coming from the mains to the switch, the other going to the PSU.
So, the order within one pair does not matter, it's AC. Just try not to shorten them.
It's a double switch for the simple reason that power plugs can be turned around and when switched off, the PSU is supposed to be without voltage in any case.
- Of course, don't try that at home.

Sometimes you'd have to attach some load like a HDD to get the PSU to turn on. Once the fan is blowing, you can check the voltages.

Looks like the standard T and inverted T shape, high, on, low.
first digit set to zero
second to 6 & 2 ?

hey, thanks for your quick and very detailed answers! should definitely have taken pics before and perhaps i have, but this project has been lying around for a few years now. picked it up again during covid, since I had a new system coming around. And i love the form factor of that case, it perfectly fits a full ATX mobo between two layers of slim 120 fans ^^.

Cuttoon wrote on 2022-02-28, 20:25:

That one seems to attach the button and pass that signal on to the mobo, right? At least that's what I take from btn_back if that black yellow cable is the original state.

yea, the turbo button has 2 paths of cables - 2 wires going out to the turbo display board, and 3 wires presumably going to the mainboard. I don't expect my x570 board to have a connector, but at least it's got a pc speaker out

Cuttoon wrote on 2022-02-28, 20:25:

This being a logical universe, attaching 5 V to any of these could not hurt.

that's a very interesting point - I guess just connecting 5v +- to the turbo button 3 pin mainboard connector with eg. a fan adaptor could work. then the whole thing would be powered through the turbo switch. or even attach it to my fan hub directly since it's a 3 pin anyways, would have to theck if the fan pin layout matches tho. it's designed for 4 pin pmw fans, so voltage would be constant afaik.

I've only disconnected the power cable from the display, so the rest of the connections is pretty certainly in it's original state in this image. just couldn't see an obvious point to reconnect the 5v.
also still have the power switch and upon closer inspection someone left matching markings on the pins and cables. the heatglue magic is also original, but less impressive 😁

weedeewee wrote on 2022-02-28, 21:16:

Looks like the standard T and inverted T shape, high, on, low.
first digit set to zero
second to 6 & 2 ?

hey, you are talking about the jumper settings right? i'll have to look a bit more into how these things are laid out -ultimately it should show 33 but i'll have to get it powered/working first ^^

First off, watch out what you do with the fan headers - those are 12 V, that would fry the thing.

Then, if "cabling" is correct, well, that makes a lot of sense.
The black-yellow in front is the switch, as is rather obvious. And the other black-yellow comes back as that twistet cable to the middle LED, the Turbo indicator.
And, the green-black is the "power LED" that should be on constantly. Usually that get's connected to the mobo, but your case is weird.

So, I can't see any markings in "btn_back" but I'd assume the lower left corner is marked + - as well and takes the Molex adapter?
Otherwise it's the upper right corner but the former makes more sense.

In any case, you could, with some cable, just connect the modern mobos "power LED" header with those pins, that's 5 V alright.

Then you'd have a display that's still being switched by the turbo button, just without the mobo knowing of it.
Or, you could replace the turbo switch with a push button and abuse it as a stanby toggle, but the power switch does the same, depending on OS settings.

Weedeewee had a hint about changing the display, you'll figure it out. Every jumper is one segment, three possible positions for "on" in one, both or neither turbo state.

Where has the reset switch gone in that foto?

Some smart person did some good thinking with that mains power switch, those markings.
So, as it should be, black and blue are the mains input that go to the side of the switch that's up in the foto.
If it then makes a random hard drive annoy you, it's not completely shot.
Before you dispose of it, if your location is as German as that PSU's branding, I'd take it.

hey, thanks for your advice!

i got some 1 pin cables today and hooked them up to the lower left corner pins. they had no markings so i just mirrored the power_led connectors.
the panel lights up on boot! i think my mainboard does not supply 5v to the power led though, because the light on the panel and power led was dim and one segment didnt even light up:

tried the original molex adaptor and it's perfect! the reset switch is already used as the power button for the system - feels a bit safer than a screwdriver ^^. turbo led/button also work.

weedeewee wrote on 2022-02-28, 21:16:

first digit set to zero
second to 6 & 2 ?

very close! with the context Cuttoon i can understand how to set the jumpers now. and since there's 15 segments on the display, the pins in the top right must control one of them.

Cuttoon wrote on 2022-02-28, 23:38:

Before you dispose of it, if your location is as German as that PSU's branding, I'd take it.

didn't get around to testing the psu yet - i'll have to blow it out before attempting anything. it was stored in my workshop so there's all kinds of dust in there. have a floppy drive here to test it with.
in any case I'll be glad to send it to you! will report here once i tested it

hey Cuttoon, just tested the PSU and the fan turns on. But both drives connected (5 1/4" and 3 1/2" floppy) didnt show any led indicators...guess they should turn on even without being connected to a board? anyways, it is yours if you like - i'll have to keep the power switch for case completeness if that makes sense ^^. didnt see any pm options on this board so i just added an email to my profile for shipping details. thanks again for the help!

also thanks to weedeewee - when i checked out the jumpers your description made total sense. if anyone with a similar board comes accross this thread, here's a sketch of the layout

as you can see there's still a hole in the frontpanel - does anyone know if they made those fake floppy covers for 5 1/4" drives too back in the day?

Nice work!

nvki wrote on 2022-03-08, 20:18:

as you can see there's still a hole in the frontpanel - does anyone know if they made those fake floppy covers for 5 1/4" drives too back in the day?

I suppose someone did, but will you find one?
Those missing covers, well, that's alway an issue with old cases. Of course, if it wouldn't be for that huge fan, you could install all kinds of drives. Certain card reader etc. front panels might still fit.
Apart from that, well, the usual approach is s trip to the next recycling facility? They never fit perfectly, but there always is hot glue.
Other than that, you'll have to improvise with sheet metal and a beige paint can?

PN about the PSU.

Cuttoon wrote on 2022-03-08, 20:42:

PN about the PSU.

hey, got the PN - since I'm a new user I'm not allowed to compose any messages it seems
no worries, i got you covered on the shipment - thanks again for your help, i managed not to trash that LED display 😁

cool!

and, PSUs, if I'm not very much mistaken, CD drives and floppys are _not_ supposed to light up in normal, idle state, only when working. Lighting up permanently was usually the sign that you screwed up the data cable and why your machine won't boot 😜
To really test them, if you were to mess with one again in order to use it, you should invest a few bucks in a cheap voltmeter. At least the 5V (red molex) and 12V (yellow) should be within a certain range to be used.

The power button of AT ones belongs to the case, not the PSU - always make sure to leave the switch or you'll end up with a deficient case.

oh and

Cuttoon wrote on 2022-03-08, 20:42:

Of course, if it wouldn't be for that huge fan, you could install all kinds of drives.

yea, welll that fan is attached to the psu, no other space unfortunately. but even without - i had done some tests and any larger drive would clash with the dram on an atx board so i abandoned that thought completely. worst case i recycle 2 covers from random large floppy drives. but those cheap plasic molded fake things have their own charm i think 😁

Hi, thank you very much for the PSU!
It just arrived today. Voltages are perfectly within specification and there's an NOS Papst Variofan standing by to calm it down a bit. (Found two of them for cheap on the bay. Weapon of choice in the mid 90s, probably not being sold any more.)

Cuttoon wrote on 2022-03-22, 11:11:

Hi, thank you very much for the PSU!
It just arrived today. Voltages are perfectly within specification and there's an NOS Papst Variofan standing by to calm it down a bit. (Found two of them for cheap on the bay. Weapon of choice in the mid 90s, probably not being sold any more.)

ha, great to see that it arrived in one piece and still works! with that fan replaced maybe it'll make it for another 20 years ^^

nvki wrote on 2022-03-22, 20:51:

Cuttoon wrote on 2022-03-22, 11:11:

Hi, thank you very much for the PSU!
It just arrived today. Voltages are perfectly within specification and there's an NOS Papst Variofan standing by to calm it down a bit. (Found two of them for cheap on the bay. Weapon of choice in the mid 90s, probably not being sold any more.)

ha, great to see that it arrived in one piece and still works! with that fan replaced maybe it'll make it for another 20 years ^^

Let's say that without that fan replaced, it may not make it another 20 minutes without being tossed out of a window. Nothing wrong about the original one, just noisy as fuck. Replacing fans is fun!

But the PSU did not take any serious abuse so far - the usual little glas tube fuse isn't in a socket but soldered on. So that never went kaflooie nad had to be replaced, since almost no one would have done that. Which is a good sign, besides the exact voltage.

There's generally a relatively good supply of AT PSUs because people use modern ATX ones with adapter, not quite trusting the old ones to not take out their prized retro system in a blaze of fire some day.
But what would be the fun in that?

Btw., my benchmark so far in PSU care is vogons member scorp with his "necroware" channel on youtube, just one example:
https://youtu.be/j1hGepWb6nY?t=471
He even opens, cleans and oils the fans. Now that's dedication 😉

Cuttoon wrote on 2022-03-22, 21:05:

There's generally a relatively good supply of AT PSUs because people use modern ATX ones with adapter, not quite trusting the old ones to not take out their prized retro system in a blaze of fire some day.
But what would be the fun in that?

hahah, guess that makes sense. when opening such an old psu you probably need to be careful to bleed the capacitors tho? i mean maybe not if it was in a basement for 20 years, but i did plug it in for testing so...please be careful ^^.

nvki wrote on 2022-03-22, 22:15:

Cuttoon wrote on 2022-03-22, 21:05:

There's generally a relatively good supply of AT PSUs because people use modern ATX ones with adapter, not quite trusting the old ones to not take out their prized retro system in a blaze of fire some day.
But what would be the fun in that?

hahah, guess that makes sense. when opening such an old psu you probably need to be careful to bleed the capacitors tho? i mean maybe not if it was in a basement for 20 years, but i did plug it in for testing so...please be careful ^^.

Thanks. You're right, the capacitors deserve some respect, hence the usual warning label on the case.
It's enough not to touch their conduits, etc. But for removing the PCB or changing the fuse, good idea.
Merely changing the fan isn't much of an operation, just snip off the old 12 V cables, attach the new turbine. So far I lived! 😉