View Full Version : Setting up P1 mother board

July 4th, 2004, 09:31 AM
Hi!! It's been a long time since I online here, so busy with study these days :(

Anyway, I've decided to rebuild my "spare parts" P166 machine!! It's in completely apart state, everything dismantled.

I have 2 motherboard, but I will use "P51430VX/250DM EXPLORER II" board since it is dated 1995, the other is 1996. I want to use older one ;)

From what I gather, it is unbranded QUI board, but is not listed on their website. It's "jumperless" board.

Here is the overview:

Now, the computer was actually a 486 when new, and the motherboard, processor upgraded into 486 case before I owned it.

My question are:

How do I connect the PSU? it's old style of connector, one long strip with 2 connection plugs of PSU. they are labelled P6 and P8. Which one goes where?

Also, have to wire up the power, reset, led switches etc, the board is marked where they should go, but how do I know the orientation of them? does it matter which way around they go?

I will have 500MB hard drive and windows 95 version A for it.


July 4th, 2004, 10:47 AM
hmm.. having some problem now.

1995 motherboard is having problems... so now using 1996 one... just have to get floppy working now!

Terry Yager
July 4th, 2004, 03:35 PM
Well, glad ya got sum'n to work for ya. For future reference, the power wires alwayg go with the black wires together, next to each other, just like ya show them in the pic. The power switch can be tricky, and if ya hook them up wrong ya may blow the P.S. (voice of experience). There is usually a diagram on the P.S. label to show which color goes where. The reset switch prob'ly don't matter which way it goes, but the LED's do matter. They just won't work one way amd will work the other way 'round. It won't hurt anything if you plug one in backwards tho, so feel free to experiment. (Now what is really tricky is to setup one of those old boxes that have the LED display on the case to show the speed it's running at. I hate those things...so many jumpers!)


July 5th, 2004, 06:20 AM
Woo-hoo it's working now! Running Windows 95 version A (FAT16) on a 4.32GB hard disk. There was something wrong with the 470MB one, it kept quitting out of the installation.

Those LED displays with the processor speed - how are they connected up? I can't work it out.

July 5th, 2004, 12:13 PM
Normally, it is three rows of pins, of which the middle is ground. By jumpering two pins vertically, you light one section of the LED. Sometimes there is a circuit which is pre-programmed to light selected segments rather than letting you jumper it.

It is not very dangerous to experiment by shortening jumpers until you get the right combination. Some motherboards with turbo support will even allow you two sets of LED displays depending on whether the turbo button is depressed or not.

Terry Yager
July 5th, 2004, 12:45 PM
Woo-hoo it's working now! Running Windows 95 version A (FAT16) on a 4.32GB hard disk. There was something wrong with the 470MB one, it kept quitting out of the installation.

Those LED displays with the processor speed - how are they connected up? I can't work it out.

I dunno, all I ever managed to do was thru trial & error till I got it to display something.


July 5th, 2004, 01:19 PM
Btw, if you have two fairly equal motherboards, of which one has plastic guides/guards around the ribbon cable connectors, choose that one! Not only will you reduce the risk of getting the cable the wrong way and possibly damage something, you also avoid accidentally bending and breaking pins on the motherboard.


Terry Yager
July 5th, 2004, 02:25 PM
Heh! I remember once breaking a motherboard by forcing a DIMM into the socket a little too hard...

I used to have an old Everex case that had a little LED panel on the front which could be programmed to display whatever message you wanted, with horizontal scrolling. That was fun to play with. I'd set it up to display some really stupid stuff soometimes.


July 6th, 2004, 12:34 AM
Thanks for the info :)

I've tried setting up the LED board, but no luck. I just can't figure out how to get power to it.

Here's the photo of it remove from the computer:

The middle wmpty row of 8x2 pins is for the ribbon connector to the LED display itself.

I have one cable left, so I assume it's to provide power to the LCD. it's a 1-pin to 1-pin connector cable.

Any idea how to get power to the display? :)


July 7th, 2004, 09:13 AM
anyone? :?

July 7th, 2004, 11:51 AM
Trace the track. Look on the underside and trace where the power FOR the LED's go to where it ends. Looks like maybe the ones in the bottom right of the pic. Use process of elimination. Is the problem you are having is what volatage to send? 4.5vdc is optimal. +/- 1v(my number, not a rule). Might have to use a special transformer to get power from the PS. I would use a multimeter to test for continuity. A circuit is a circle, and an open has no power to it. Being that its out of the case that's a given. Look at those pins on the bottom right, they look suspicious. Best bet is to get a notepad (a real one not the win one) and trace each of the lines on the bottom using the pins on the top. Good luck!


July 8th, 2004, 03:30 AM
I hated modifying those case displays. The one time I did it correctly was because I had some little piece of paper showing the way to set it and it came with the new case I had bought. Here's a web site I found, hopefully it matches yours.


As far as power, there is a set of jumpers on the right side 3 sets of 2 rows and the top is 5V and GND. All of this appears to be in the web site above! Let me know if this helps.