Thank you! I did some more diggin and found the service manual for the
display (Panasonic TR-60S1A, see here:
https://www.opweb.de/english/company/Panasonic/TR-60S1A)
There is is a timing chart (see below). It looks an awful lot alike NTSC
to me, can somebody confirm?
Best wishes
Jens
On 2021-04-10 12:28 a.m., Adrian Godwin wrote:
It's easy enough to extract the sync signals, as you've seen. It may
not be particularly difficult to modify the TTL input to analog, or to
create a TTL level signal if you don't need a grey-scale. On many
general-purpose monitors like that they could often be built for
either standard - the microvitec Cub popular with the BBC
Microcomputer had that option.
But the critical thing is that it runs at the right speed. CRT
circuits are built around the line oscillator which generates the
horizontal scan AND the EHT voltage. It was only when multisync
monitors came along that the optimisation was split to reduce the
dependency. And if the frame frequency is wrong, you will often have
problems getting a full frame scan when you force it into sync.
So the first thing is that you need to make sure the 8920 monitor ran
at either PAL or NTSC rates so you can choose a raspberry pi format to
match. There's a good chance it's NTSC but later monitors like the
ones in the 54 series of digital scopes were more like the IBM
standards MDA and EGA (CGA was NTSC).
On Sat, Apr 10, 2021 at 4:28 AM jb-electronics
<[email protected] <mailto:[email protected]>> wrote:
Hi all,
This is a bit of an off-topic question, but I hope there will be
somebody here that can help. I have bought a new-old stock monochrome
CRT for a HP Agilent 8920A, basically this unit here:
https://www.ebay.com/itm/273930914548
<https://www.ebay.com/itm/273930914548> .
It looks to me that it is just a rebranded OmniVision 6" display:
http://www.omnivisionusa.com/Industrial-LCD-CRT-Monitors/replacement-crt/crt-monitors/6-inch-kit-.html
<http://www.omnivisionusa.com/Industrial-LCD-CRT-Monitors/replacement-crt/crt-monitors/6-inch-kit-.html>
Now unfortunately it takes TTL video as input. But I have a composite
source (a Raspberry Pi). How can I convert composite into TTL? I
basically need to extract Hsync and Vsync and feed it separately
to the
unit, okay. There is an old circuit here that does just that:
https://www.elektormagazine.com/magazine/elektor-198812/47485
<https://www.elektormagazine.com/magazine/elektor-198812/47485>
But I know there are also dedicated chips, like the GS1881:
https://www.mouser.com/datasheet/2/761/GS1881_GS4881_GS4981_Datasheet-769183.pdf
<https://www.mouser.com/datasheet/2/761/GS1881_GS4881_GS4981_Datasheet-769183.pdf>
So basically here is my question: before I dive into this any
further,
is there any chance of success? What is the optimal choice? Or is it
quite unlikely that I will be able to convert the signals? I mean,
even
if I manage to extract Hsync and Vsync, is it likely to work?
I am sorry for the naive question, but I am no expert on video
signals,
and it would be nice if anybody more experienced could chime in
with a
few words of caution/experience.
Best wishes
Jens
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