VOGONS


First post, by Stull

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I recently picked an IBM 300GL, model 6282-87U, with a Pentium 233 MMX, 2.5GB HDD, 2MB onboard CL video, 64MB RAM, etc. Nothing special.

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Here's the PDF documentation. This thing has some weird kind of proprietary power supply, maybe early-ATX-ish, but with AT-style connectors and some extra stuff (two separate 3V connectors and a 5V, P9, P10, P11):

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So anyway, I think I already know the answer to this question, but if this power supply ever dies, would there be any way to hack an ATX power supply to make it work with this thing?

Reply 1 of 13, by TELVM

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What a nightmare 😵 . Overall sounds like a booby-trapped delirium on the early ATX standard.

On P2 they used yellow for -5V.

On P9 they used purple for +5V, and green for 'CONTROL' (which probably = PS_ON# ).

On P10 they used brown for +3.3V. Etc. etc.

20-pin-atx-pinout.gif

Guess a standard ATX PSU could be spliced and carefully soldered to all these exotic connectors, then plug and pray for the best.

Let the air flow!

Reply 4 of 13, by Callahan

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How are your dip swithes set for 233MMX?
this multiplier isn't described.

EDIT:
Found that thanx to your manual!
Multiplier setting is same as 100MHz for 233MMX.

My 6282 is full of life. If U want i can measure voltages.

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Reply 5 of 13, by raymangold

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It's actually a *very* unique computer. Known as the 350 (which as a result has some similarities with the PC 340) it was the first of the PC 300 series to have the "GL" suffix. I would like to remind everyone that the 6282 300GLs or PC 350s were designed just before the ATX was in full effect and were also very early machines to sport USB and optional onboard ethernet. So it is totally expected that an AT power supply would have been used as development most likely happened in 1995. In fact, the 6282 is IBM's first Pentium 1 machine capable of running 233 Mhz Pentiums natively.

The PC 300 that was released a year *later* does use ATX, it's the 6562 300PL. It also used the updated Triton II which meant EDO DIMMs exclusively-- unlike the 6282 which could use both SDR and EDO DIMM modules.

Another thing not mentioned is that the optional front 80mm fan uses a proprietary two pin socket-- although I would recommend just using a standard fan with a molex adapter if you're using a CPU faster than 166 Mhz (apparently IBM was confident that the giant socket 7 heatsink was adequate for passively cooling 166 and downward). Also the diagram on the internal lid states "VESA FUTURE" instead of "VESA FEATURE", clearly VESA wasn't the future...

If the PSU in your 300GL 6282 is dead, I would advise purchasing a FRU replacement-- or you'll have to open it up and troubleshoot what component failed. If you want one with an ATX power supply, get a 6562 or its brother in a tower form factor, 6592. Reworking the power supply with an ATX will be more problematic as AT power supplies are hard switching and not soft switching.

Reply 6 of 13, by alexanrs

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You might have luck with a modular PSU. Just de-solder the cables from the IBM PSU, sacrifice the ATX-POWER cable that comes with it and make a nifty modular cable that works on that weird standard (which then could be used with any modular ATX PSU in the future).

Reply 7 of 13, by raymangold

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alexanrs wrote:

You might have luck with a modular PSU. Just de-solder the cables from the IBM PSU, sacrifice the ATX-POWER cable that comes with it and make a nifty modular cable that works on that weird standard (which then could be used with any modular ATX PSU in the future).

AT and 'old school' ATX use -5v for ISA. New ATX power supplies have added four extra pins to the main power connector and removed -5v. So if you need ISA; using most modern ATX PSUs will not be sufficient unless you can add a -5v regulator in there.

EDIT: I should also add that those earlier -5v capable ATX power supplies generally used 92mm fans instead of 80mm making them a bit taller. So even if you want to use a properly old style ATX power supply, it may be hard finding one with an 80mm fan like in the PC 350 (which is funny as IBM was being a bit ahead of the game using a smaller form factor on an *AT* class PSU).

Reply 8 of 13, by raymangold

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TELVM wrote:
What a nightmare :dead: . Overall sounds like a booby-trapped delirium on the early ATX standard. […]
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What a nightmare 😵 . Overall sounds like a booby-trapped delirium on the early ATX standard.

On P2 they used yellow for -5V.

On P9 they used purple for +5V, and green for 'CONTROL' (which probably = PS_ON# ).

On P10 they used brown for +3.3V. Etc. etc.

20-pin-atx-pinout.gif

Guess a standard ATX PSU could be spliced and carefully soldered to all these exotic connectors, then plug and pray for the best.

By "they" I assume you mean ASTEC and not IBM as the Delta-made power supply for 6282 uses different colours:
10417653_392738130905037_3825570150853380455_n.jpg?oh=ba6e7deee77df0e753cdaf712bbb2e16&oe=54FB4854

Reply 9 of 13, by alexanrs

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I wonder if someone could ever make an "add-on -5V regulator". AKA a dummy ISA board with a Molex connector that generates -5V and has that output routed to the ISA -5V pins. Or someone could just get one of the few ISA boards that do require -5V (AFAIK most of them don't, with notable exceptions like PAS16, SB 2.0 and LAPC-I), mod it and add the -5V regulator as some sort of "daughterboard"... or apply that same idea and make an ATX-ATX cable with a little board in the midle. Surely you'd need a diode there to keep things from breaking when you put that in a system that actually provides -5V, but this should be feasible.

Reply 10 of 13, by jwt27

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alexanrs wrote:

I wonder if someone could ever make an "add-on -5V regulator". AKA a dummy ISA board with a Molex connector that generates -5V and has that output routed to the ISA -5V pins. Or someone could just get one of the few ISA boards that do require -5V (AFAIK most of them don't, with notable exceptions like PAS16, SB 2.0 and LAPC-I), mod it and add the -5V regulator as some sort of "daughterboard"... or apply that same idea and make an ATX-ATX cable with a little board in the midle. Surely you'd need a diode there to keep things from breaking when you put that in a system that actually provides -5V, but this should be feasible.

My ISA extender cards have a -5V regulator 😉
Short on ISA slots? Try this.

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Reply 11 of 13, by nuno14272

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Sorry to dig out this thread..

I'm having the same problem, my at'xish 300GL has one integratead circuit inside the power supply that has exploded, so i'm making a ATX conversion

pretty much all done, except for the white P2 -5v pin... where it goes ? because i have a ATX-AT converter, and this white pin goes to a empty slot... at least my atx as no -5v ??

any ideas ?

Last edited by nuno14272 on 2020-04-10, 17:39. Edited 1 time in total.

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000

Reply 12 of 13, by nuno14272

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I've monted the new power supply, ignoring the white -5v power pin....

the computer has power but it gaves me just beeps... 1-1-3 beep burst.
dipswitches are ok. bios jumper i don't jnow heres the 1-2 or 2-3 but neither works.

i've not conected P9,,, is it really necessary ?

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000

Reply 13 of 13, by nuno14272

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hello, i've managed to make a custom -5v rail using a 7905 and using the -12v wire...

i've also updated the bios to english..the original was deutch (holand)..

conclusion. the pc is booting, but i'm struglingg to install a O.S... i cant find in bios nothing pointing to the Startup sequence.
and even if i use a dos 6.22 original setup disk1 or a boot disk the computer doesn't boot from drive A..

dammit this fucking pc.

1| 386DX40
2| P200mmx, Voodoo 1
3| PIII-450, Voodoo 3 3000