VGA 9 pin HP output scaled to VGA 15 pin - Page 1
Forum section: electronics / projects

author: time27
author_rank: Contributor
timestamp: January 02, 2021, 11:13:56 pm
content: I have a HP35670A Dynamic signal analyzer. At the back it has a 9 pin VGA output.We been able to pull the voltage down and connect pin to pin so we get an image on a monitor.However multisync monitors are limited to 24kHz - this HP signal is 55Hz and display is [500,400].I get a display but I need to adjust the scan rate - so its on a very limit of multisync monitor.Is there a way of upscaling the signal to 48Hz for a pixel.here are some jpgs of what I am getting..

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 03, 2021, 04:03:12 am
content: That's a tough one. I couldn't download a manual from HP without needing to sign in.The data I did find does say 9 pin VGA, but this is not a standard PC connector but I guess you know the pinout.I can't really tell from your post what the specs are but there are many RGB upscalers on eBay used by retrocomputing people.You might get away with thishttps://www.ebay.ca/itm/Arcade-Game-RGB-CGA-EGA-to-VGA-HD-Game-Video-Converter-Output-Board/253407215602?hash=item3b003f3ff2:g:egAAAOSwRVJftD46Is this a digital or analog video signal? How many colors?

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 03, 2021, 06:32:33 am
content: For mine at work I used an older 4:3 LCD screen. It's been a long time since I set it up. I don't recall how much I had to adjust the controls, but it did work well. Find the oldest LCD you can.

author: BrianHG
author_rank: Super Contributor
timestamp: January 03, 2021, 07:15:13 am
content: If the video modes are identical to this slightly newer HP Analyzer and they seem to be, take a look at this project here:https://www.eevblog.com/forum/projects/hp-8594e-replacing-the-green-crt-with-lcd/msg3022500/#msg3022500You'll get digital pixel-pixel sampling and color palette options.Though, it taps the internal CRT video connector.Sorry, different video mode.

author: m k
author_rank: Super Contributor
timestamp: January 03, 2021, 05:22:34 pm
content: Quote from: time27 on January 02, 2021, 11:13:56 pm55 x 400 is 22kHz, less than NTSC hires and you have a picture so it's not sync.Manual says that Nec Multisync 3D is suitable but it's aspect ratio is 4:3 so your 5:4(SXGA) can be difficult.Back in the day those different multisync resolutions were not dynamic.Those monitors were clicking and clacking around when they changed their modes.Means that even if you find a suitable h-sync it may not work properly.In the picture,the first line of inverted text has something on its left, is that the last column from right?If so then adjust the picture width narrower and horizontal position to the right.It's also possible that time between h-sync and first pixel is too short but then all scanlines should start from the very edge of the physical screen.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 19, 2021, 08:51:05 pm
content: Here is the internal help message regarding the external VGA connection, along with the external monitor status message.

author: time27
author_rank: Contributor
timestamp: July 17, 2022, 10:30:23 pm
content: Thank you after many painful events I built an FPGA box but one can just buy one. Found that out littlie late. Regards nick