18 Jan
2016
18 Jan
'16
7:51 a.m.
What is the exact model number of the video card?
I am assuming it's an HP98204 of some flavour. The HP98204A uses (US, RS170) TV rates
and
can be connected to any composite monitor that expects that. A lot of TVs (rather than
monitors)
in Europe can accept that and have composite inputs still, perhaps on a SCART socket.
However the more normal video card in the 9000/217 (aka HP9817) is the HP98204B. This
does
have a composite output but at rather odd rates. There was a specal 'HP'
(actually a Samsung
chassis, and it shows!) monitor for this. I thinkl finding somethng that will lock to the
video output
of that card is going to be 'interesting'
Do you have the original HP monitor? If so, what model is it?
-tony
Hi Tony,
indeed this machine has a 98204B video board (intended to work with a 35721 monitor, which
I don't have). I have not yet found the specs for its composite signal.
I find many $20 converters/scalers for composite to VGA on amazon or ebay but I am not
sure whether such a thing would work for me. Obviously they seem to work for many computer
games (SNES, Nintendo) and for some hobby computers like C64, Amiga etc. (e.g. "RCA
Composite AV S-Video to VGA Converter Box").
Next I see $50 devices like "Mini Composite RCA CVBS AV To HDMI Converter (Input: AV;
Output: HDMI)" which may also be an option, but only seem to scale to a fixed HDMI
resolution, which may be unsuitable for the HP-resolution of 512x400 (or 512x390?).
Finally I see $200 converters/scalers which are a bit expensive just for trying to see
whether they work (e.g. "Atlona AT-AVS100 Composite/S-Video to Component/VGA
Scaler").
I have also contacted Jon from the HP-Museum to see what their solution is.
Regards,
Martin
18 Jan
18 Jan
12:39 p.m.
On 1/18/2016 10:51 AM,
Martin.Hepperle at dlr.de wrote:
this machine has a 98204B video board (intended to
work with a 35721 monitor, which I don't have). I have not yet found the specs for its
composite signal.
It's around 25khz. The 98204B is
normally used with the 35721 or 35731
640x400 mono monitors. The 98543A
gives you RGB, but is also 640x400 (25khz).
I find many $20 converters/scalers for composite to
VGA on amazon or ebay but I am not sure whether such a thing would work for me. Obviously
they seem to work for many computer games (SNES, Nintendo) and for some hobby computers
like C64, Amiga etc. (e.g. "RCA Composite AV S-Video to VGA Converter Box").
None of them will work here.
Next I see $50 devices like "Mini Composite RCA
CVBS AV To HDMI Converter (Input: AV; Output: HDMI)" which may also be an option, but
only seem to scale to a fixed HDMI resolution, which may be unsuitable for the
HP-resolution of 512x400 (or 512x390?).
Won't work here.
Finally I see $200 converters/scalers which are a bit
expensive just for trying to see whether they work (e.g. "Atlona AT-AVS100
Composite/S-Video to Component/VGA Scaler").
Won't work here.
I have also contacted Jon from the HP-Museum to see
what their solution is.
You need a monitor (or converter) that
supports 25khz. Here's the extent of my
own research:
25khz 640x400 SOG monitors
LCD
- NEC LCD1510+ (not tested)
- NEC LCD1810 (LA-1831JMW-1)
Mac + PC -- fair performance, poor
scaling.
HP 300/98543 -- works, but banded
background cannot be completely
faded to black (I got rid of my
1810's for this reason).
- Viewsonic Vp150
HP300/98543 -- works well, great
background, colors only fair.
- Viewsonic VP181
HP 300/98543 -- not perfect but can
be adjusted ok.
banded background *can* be faded to
black.
- J.
1:07 p.m.
indeed this machine has a 98204B video board (intended
to work with a 35721 monitor,
which I don't have). I have not yet found the specs for its composite signal.
It is normal composite video voltage levels with faster-than-normal horizontal scan rate.
If you have a frequency counter (or something that can be used as one, then put the
98204B
text board in the topmost position of the 9817, leaving out the graphics board (the
machine
will run without it) and take the top casing off the 9817. Take care to avoid the live
mains and
worse on the PSU board, power it up, and check the HS and VS pins of the 6845 (the only 40
pin IC on the board)
Most, if not all, cheap composite video converters assume US or European TV rates and are
not going to lock to this thing. If anybody knows of an interface that will work, I'd
be
interested to know about it too (I have a 9817 with the 98204B card, fortunately I do
have the right montor for it).
-tony
3261
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ard＠p850ug1.demon.co.uk -
js＠cimmeri.com -
Martin.Hepperle＠dlr.de