Oric computers, TTL monitor

Last night's skip diving session yielded a Goldstar MBM-2233A
"data display monitor". With the Oric mainboard Fabrice gave me
this could mean having a working Oric again.

A post-it note on the case says "TTL monitor". Uh-oh. Yes, the
video output of the Oric should be TTL-compatible, since the
signals come out of a 74LS365 but if the monitor's input are TTL
in the sense of "off or on", getting shades of green by
weighting the RGB signals with different resistors won't work.

Google has no match for "mbm-2233a". There are two matches for
"mbm-2233" but they're not of much help. There are two rca/cinch
sockets in the back labelled "video in" and "video out" and a
HI-Z/75R switch. Made in Korea in 1986.

Any advice for using this monitor with an Oric, other than "just
try it" ?

--
Andr?Majorel <URL:http://www.teaser.fr/~amajorel/>
(Counterfeit: XXXX@XXXXX.COM XXXX@XXXXX.COM )
"J'baiserai la France jusqu'?ce qu'elle m'aime." -- Un rappeur

XXXX@XXXXX.COM ...

Is this a colour or b/w only monitor ?
Hopefully, the Oric only has 8 colours, so each RGB signal is actually "on or
off"...
But if the monitor is only a "pure" B/W monitor, you might end up with
connecting only one colour component...


Do you mean those two rca are the only sockets on this monitor ?
It sounds strange a monitor would have only a single TTL input, how would it
synchronize in this case ?
About the High impedance / 75 ohm switch, I guess it's there to adapt to either
a real TTL output (0 - 5V) or a usual video output (0 - 0.7V), don't you think
so ? In any case, I wouldn't be afraid of connecting one of Oric's colour
component, but I don't see how you will get a stable image if no SYNC is fed to
your "data monitor"...

Cheers,

Fabrice

It's a monochrome monitor, that's why I was referring to the RGB
weighting technique. That's what I used to do on my now defunct
amber Philips monitor. That way, you have 8 shades of amber
(green) instead of 4.


Right.


The two other monochrome monitors I've seen only have one RCA
socket for video input, IIRC. I guess the sync is combined with
the main signal.


Hadn't thought of that. High impedance for TTL and 75 ohm for
0.7V ? That sounds plausible.


I'll give it a try. Thanks.

--
Andr?Majorel <URL: http://www.teaser.fr/ ~amajorel/>
Baby thugs, bad spuds and mean things
Living for today or maybe even yesterday

"Andre Majorel" < XXXX@XXXXX.COM > wrote


I had problems working with monochrome. Come colours didn't show.
Couldn't you get a TV card for your PC ? These can be got for ?0 or so. You
could plug the Oric into that and get colour, couldn't you?

Steve M

No problem here.


Sounds like a good idea.

On second thought, maybe not. I think that owning a tuner card
subjects you to the "redevance" now (yearly fee supposed to help
finance the French public television channels).

--
Andr?Majorel <URL: http://www.teaser.fr/ ~amajorel/>
(Counterfeit: XXXX@XXXXX.COM XXXX@XXXXX.COM )
"J'baiserai la France jusqu'?ce qu'elle m'aime." -- Un rappeur

Then you'd need to have a proper signal out of the Oric, because I've
been testing an Atmos plugged to my PC TV card thru the UHF output, and
never managed to have nice colors, and the picture was moving...


I've read documentation about this recently with a specialist as I have
both a tuner card and TV thru the Internet via my ISP (Free). If you
read the law, it's stated that anything designed to recieve TV (even
broken) leads you to pay the tax. But other texts explaining it say that
this statment excludes computing installations - maybe because computers
are not initially designed to recieve TV ? I must say we didn't understand.
So it's not very clear...

Simon