Microdisc Power Supply Pinout

If you want to ask questions about how the machine works, peculiar details, the differences between models, here it is !
How to program the oric hardware (VIA, FDC, ...) is also welcome.
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Microdisc Power Supply Pinout

Post by freaktmp » Wed Aug 11, 2010 5:15 pm

Hello people,
I just bought an Oric Microdisc without a power supply. Could someone please tell what the pinout of the power supply unit of the oric microdisc. Of course, I am refering to the DIN plug that powers the drive unit.

Edit: with >> without, how 3 letters change everything!

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Post by ibisum » Thu Aug 12, 2010 11:48 am

Oh man, where did you buy this? I'm dying to find one myself as well ..

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Post by freaktmp » Thu Aug 12, 2010 12:17 pm

There was one in Ebay a few weeks ago along with a MCP-40 printer. I got them both. I'd like to use it with my HxC floppy emulator, but first I have to find a way to power it up!!!

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Post by freaktmp » Tue Aug 17, 2010 8:08 am

Well, since none volunteered the information I tried to dig a little bit further. I'm only interested in powering up the controller board, since I'll be using the HxC floppy emulator.

I opened up the microdisc and here is what I found.

Image

It appears that the orange wire is 5v, the red is 12v and the black is ground.

Image

So I used an external power supply to power the controller board.

Alas it doesn't work. All I get is garbage on screen:
Image

What I've tried:
1.I've verified the voltage with a multimeter
2.I've tried with both an oric 1 and an atmos
3.I've tried different floppy cables
4.I've tried with the floppy emulator connected and separately.

FYI this microdisc was sold to me as not working, probably because there was no power supply to test it with.

Does anyone have any other suggestions? If the rom is bad could someone assist me in replacing it?
Last edited by freaktmp on Tue Aug 17, 2010 11:00 am, edited 1 time in total.

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Xeron
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Post by Xeron » Tue Aug 17, 2010 10:04 am

The pictures don't work, even if I paste the URLs :-(

Can you upload them somewhere like Photobucket?

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Post by freaktmp » Tue Aug 17, 2010 11:00 am

I'm sorry!!!! :oops:

Should work now!

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Post by Xeron » Tue Aug 17, 2010 11:25 am

Yep, that fixed it :-)

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Post by Twilighte » Tue Aug 17, 2010 3:00 pm

Freaktmp, check private message i sent you.
I thought the Microdisc only took one 5 volt connection. Only the D/D may need more.

The original Opelco D/D interface had a separate transformer and rectifier supplying 5v DC to microdisc and another transformer for single/dual 3" D/D's.
Beyond that i don't remember anymore.

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Post by freaktmp » Tue Aug 17, 2010 4:47 pm

Well I am no electrical engineer (far from it!) but this is how I understand it.

Of the four pins of the din plug, one is not connected, another (black) is ground and there are two more, one orange and one blue.

Image

The blue wire connects to the the first voltage regulator (mounted externally on the case) that outputs 5v. The orange wire connects the to the second regulator that outputs 12v.

Image

I can't reach any conclusions as to what the input voltage is, but I do know that 12v do reach the controller board. If they are used or not, that's another story.

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Post by Dbug » Tue Aug 17, 2010 5:21 pm

I seem to remember having read in the CEO mag that some Microdisc had the +12/+5 convention reversed on the Molex connector.

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Post by freaktmp » Tue Aug 17, 2010 5:31 pm

I didn't follow the pc standard blindly, I just read what's written on the floppy drive PCB. So unless it is the opposite than what written on the PCB I am ok...

Plus it is corroborated by the voltage regulator outputs, so I don't think the problem is the voltage.

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Post by nobbysnuts » Tue Aug 17, 2010 10:03 pm

HI I will dig a microdisc psu out on weekend and confirm outputs and dont plug the original 9v oric psu in at same time as this can cause problems :shock:
I seem to remember andrec,s site having a lot of info on this subject
ONLY DEAD FISH GO WITH THE FLOW

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Post by freaktmp » Wed Aug 18, 2010 10:23 am

Well I know that the microdisc power supply also powers the computer, but I have no choice but to use the original oric power supply to power the computer. I make sure to power up the controller board first and then the computer. I haven't tried to power them up at the same time yet, I'll try it when I find some spare time.

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Post by freaktmp » Wed Aug 18, 2010 2:58 pm

I think I have the answer:

http://andre.cheramy.net/trucs/alimenta ... rodisc.pdf

"Here is what is written on my Microdisc
power supply: 9V DC @ 1,6 A and 12V DC @ 0,9 A.
The 1,6A allows to power an Atmos plus two Microdisc
units (a Master and a Slave), each equipment having its
own regulator to extract +5V from the 9V. "

So I guess I was right about the voltages that power up the board. So why doesn't it work?

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Post by nobbysnuts » Wed Aug 18, 2010 5:33 pm

Hi not quite sure what you mean by powering up one by one ,the original psu feeds both so both need powering up from same psu at same time I cant find my microdisc at mo but had little success as yourself using seperate supplies before I got a proper psu .(15/9/0 volt as the regulators need a voltage difference to work,)also some switching pc psu's don't work
if its connected with correct voltages and it is a duff microdisc does hitting the red reset button on microdisc switch it back to orics rom(what is the effect of this)
ONLY DEAD FISH GO WITH THE FLOW

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