Microdisc connectors

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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Chema
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Re: Microdisc connectors

Post by Chema » Mon Feb 18, 2019 2:22 pm

Indeed! I don't know why the Telestrat needs the -12, I suppose for the RS-232 port (which uses -12 volt to signal logical 1, IIRC).

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iss
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Re: Microdisc connectors

Post by iss » Mon Feb 18, 2019 8:41 pm

Chema wrote:
Mon Feb 18, 2019 2:22 pm
... why the Telestrat needs the -12, I suppose for the RS-232 port
That's right, it's only for the RS232 compatible output.
Interesting remark can be found on Telestarat's schematic: "le -12V sera fourni par l'alimentation (PL6) à partir du N°1000"
Which tells that for serial numbers below 1000, Telestrat has an internal DC-DC +12V to -12V converter and for numbers > 1000 the PSU should supply the -12V. But I'm sure the numbers 229, 1089 and 1427 are absolutely the same! All three have the converter. ;)

The schematics of the converter is interesting too:
Telestrat-DC-DC.jpg
OPAmp LM386 is the sound output amplifier of the Oric and here another one LM386 is used in an unusual way - as generator for the charge pump of the negative voltage.
(I made such converter to supply with -12V an Apple][ disk and it worked fine, but later I changed it to a better one from China :))

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iss
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Re: Microdisc connectors

Post by iss » Mon Feb 18, 2019 9:24 pm

But let's go back to the PSU :)...

Previously I've posted in this thread picture of my Oric+Microdisc PSU in bad condition.

And here is my Telestrat PSU in even worse condition:
psu1.jpg
Unfortunately I've got it as in the picture - all wires are cut, the transformer is in rust and what can't be seen - is the smell :(

But I think I found good solution for replacement which can be adapted as universal supply for more disk drives too.
Stay tuned for pictures :).

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Symoon
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Re: Microdisc connectors

Post by Symoon » Wed May 01, 2019 5:54 pm

Hi, I'm trying to test a Telestrat, but I forgot which plug goes where.
As stated before in the thread, each plug can go in the Telestrat, or the Microdisc :-( Zero indication on what to use where.
ISS details given a few posts before state for the Telestrat "the closer cable from the power switch, and the shortest", but on my power, both are the same length and, of course, are equally distant from the power switch.

I have the same plugs than Dbug's ones, if I understand correctly the one that has "less plastic" goes in the Telestrat, at least for his PSU... Do I take the risk?
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iss
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Re: Microdisc connectors

Post by iss » Wed May 01, 2019 6:06 pm

IMG_1414b.jpg
Very interesting PSU - the box is painted metal, right?
If so I have 2 (ot maybe 3) boxes the same design but for floppy drives. (will search them and if found will post pics).

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Re: Microdisc connectors

Post by Symoon » Wed May 01, 2019 6:08 pm

Thanks a lot, once again! :D :D :D I'll take note on a paper that will remain in the PSU box, for later.
PS: actually one could have said that the plug under the other is closer from the power switch... And it's also the one that has "less plastic"!

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