Hi, all,
My shiny new (to me) HP 89441A has an analogue video output, but none of my LCD monitors can sync to it--one says "out of range" and the other two just sit there sulking. So I think that its vertical sync is too fast for them.
Any recommendations for LCD monitors that can handle Y2K-ish vertical sync rates?
Thanks
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Pick one at random and it's sync or swim.
NT
Vanished without a trace. ;)
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
That's strange. 600x400 is not a standard VESA mode and is NOT listed in the typical VGA timing tables: Also, the vertical sync rates do not go down to 25.5KHz. Skimming the list, it looks like 640x480 has the lowest horiz sync frequency of
31.5KHz.My 1.05 fudge was off. This calculator produces 24.90KHz for 640x400:
25.5KHz is something that was used in CGA/EGA arcade game monitors. Maybe this converter? (Not sure):-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Wed, 28 Feb 2018 18:48:29 -0800, Jeff Liebermann wrote: (...)
Short list of 3 monitors that go DOWN to 24KHz: Apparently, some early game machines used 24KHz.
Oh swell, change everything. We now have a different sweep rate in the 2002 spec sheet: See Pg 14: External monitor output Format Analog plug-compatible with 30.15 kHz multi-sync monitors Impedance 75 Ohms Level 0 to 0.7 V Display rate 57.43 Hz Horizontal 30.15 kHz refresh rate Horizontal lines 400
So, now it has to work at 30.15KHz and 60Hz. That's close enough to VGA 31.5 or 31.8KHz that any multisync monitor should work.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
That's strange. 600x400 is not a standard VESA mode and is NOT listed in the typical VGA timing tables: Also, the vertical sync rates do not go down to 25.5KHz. Skimming the list, it looks like 640x480 has the lowest horiz sync frequency of
31.5KHz.My 1.05 fudge was off. This calculator produces 24.90KHz for 640x400:
25.5KHz is something that was used in CGA/EGA arcade game monitors. Maybe this converter? (Not sure):-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 ====================================================================== 640x400 was the highest resolution mode on the Amiga 1000 but since it was NTSC compatible I don't think the horizontal sync was 25.5 kHz. Had a pipe freeze and flood my garage three years ago, and even though it didn't get wet I went ahead and scrapped my A1000 and Amiga monitor in the cleanup. Lots of sentimental value (wrote my PhD thesis on it in 1988) but time passes :-).
I ask a favor. Can you post the search string along with the results? I had tried to find info on 25kHz monitors before your post, and my results were dismal to none.
You know, instead of working for a living, you should write a book on how you do your search strategies. You could call it "Google-Fu for the smart people". (XXX for Dummies is already taken.)
You already know how to find the cheapest book dealer, and how to sell it on Amazon. You would become world famous and the richest person on the planet. Businessmen and imnportant politicians would come to you asking for help. They can afford any price you ask.
This is an opportunity you cannot afford to miss. You have special skills that nobody else has, and it's time to turn it into profit. The world is yours if you will just reach out and take it.
Need I say more?
Well, I noticed that everyone was rounding off the various frequencies. I was originally looking for anything that would sync down to 25.5Hz. So, I searched Google for: The last search produced this page: which provided the game connection. However, all this may have been wasted since I found the 2002 specifications for the Agilent 89441A, which are quite different. Phil gets to measure the frequencies with an oscilloscope to see which one is correct. I don't believe that HP would use a non-standard 640x400 Amiga monitor but I've seen stranger things.
I actually started such a document. It won't be a book but more like a web page. In the distant past, I did the tech edits on an SCO Unix book. I really don't want to repeat that nightmare.
Notice that I've reduced the Google search string and other URL's to just what is needed to perform the search. The tracking info, unique identifier, and such are not needed. If ever throw together a web page, that will be a key part. The rest is technical vocabulary expansion. You can't search for something if you don't know what it's called. So, I do a fair amount of buzzword and acronym excavation before I do the actual search. Lastly, I prefer to do image searches. I picture is worth 1 kilo-word. My first posting in this thread included a link to a photo of the back of the 89441A. From the original question, I thought it has an RCA phono or BNC connector with composite video. Although VGA is analog, it wasn't obvious until I saw the rear panel connector. I hope this helps.
Sigh. I do not want to be famous and don't need to be the richest person on the planet. Fame and fortune tend to fleeting. I don't want to attract politicians and other vermin. They may be able to afford my exorbitant consulting rates, but that's useless if they don't bother to pay their bills. My worst payers are my wealthy clients and customers.
I have most of what I want in life. If you want to motivate me, it will take something quite different from flattery. Try to work out what might motivate me, what makes me run, why I do things, and what gets my attention. Just one problem. Even if you guess correctly, I won't admit it. To make it easier, ask yourself a simple question, "What problem is he trying to solve"? If you can work that out, the other parts of the puzzle will easily fall into place.
I don't know. It's not my decision to make.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Vertical or horizontal synch mismatch?
Most multisyncs I have encountered will play almost anything back to CGA but with some bits lost round the edges and bad pixel fuzziness. You may have been unlucky or there is something odd about the video out from the HP. What does it look like on the scope?
FWIW The much older NEC does everything from 640 upwards. But my more recent HP LP2475 claims 800x600 as its lowest working resolution so maybe you do need one that is older and can do 640x480 VGA base rate.
Something off eBay from about the right era perhaps, but I'd be very suspicious that the video out isn't quite what it claims to be.
Measure it and compare with known rates that your PC video cards supports. My hunch is that the HP output is classic VGA.
-- Regards, Martin Brown
Amazing. Thanks.
Grin, We use car back up monitors to look at CCD camera video. Would that work?
George H.
Great write-up Jeff, your insight is always helpful!
We have had a lot of trouble with various versions of the GBS-8200 - in a number of cases it works for a while then turns green or looses sync and this annoys our customers no end. What we do now for interfacing older arcade games to LCD monitors is to run the game for up to a week before releasing it back into the wild, only then do we know the GBS-8200 or whatever else we try is stable enough for prime time.
25.5kHz is only used in EGA series such as Atari Paperboy and others, whereas CGA games were all roughly 15kHz, with earlier games wandering around the standards a bit. I once spoke with an old engineer at Wells Gardner about why they had so many different sync boards for CGA games from the late 70s and he told me that no two games were the same frequency and they had to tweak the design in a number of cases to get their monitors to work reliably with various games.I have yet to find a reliable 'universal' converter, for CGA or EGA arcade games, that comes in under $200USD and works for all games and the various 3:4 VGA LCD monitors.
Your mileage will vary!
John :-#)#
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Dunno. None of my monitors work, and the oldest of them is from about
2005. I suppose I'll have to hang a scope on it as folks have suggested.Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
I could ship you one, but they are only ~$15-20 on amazon, probably cheaper for you to order it. (I got some flaky amazon ones, and ended up buying a box full from China on ali-baba. So if it does work, but 'flaky', I'd be happy to ship a good one. It does PAL and NTSC... something like this..
But with more stars. :^)
George H.
yeah if you do that. we can possibly program our VGAs to the same rate and test whatever random hardware we have on-hand.
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