WTB: HP monitor 82912A (82913A)

[Michael Fehlhammer]

I am searching for a nice old small crt monitor from HP, preferably the 9 inch 82912A, but the 12 inch 82913A also is suitable.
The monitor is intended to be a good companion for the IL-calculators 41C, 71B, 75C (and an IL- video interface, of course).

[Dave Frederickson]

(03-30-2015 08:20 PM)Michael Fehlhammer Wrote:  I am searching for a nice old small crt monitor from HP, preferably the 9 inch 82912A, but the 12 inch 82913A also is suitable.
The monitor is intended to be a good companion for the IL-calculators 41C, 71B, 75C (and an IL- video interface, of course).

The Monitor output of the 82163 Video Interface feeds in nicely to the composite input of most LCD monitors. I know, it's not vintage, but it looks good.

Dave

[Michael Fehlhammer]

Hi Dave,
yes I know, I tried that already, but I prefer the appearance of the old CRTs. They make me feel thirty years younger! :-)

[Dave Frederickson]

(03-30-2015 09:15 PM)Michael Fehlhammer Wrote:  Hi Dave,
yes I know, I tried that already, but I prefer the appearance of the old CRTs. They make me feel thirty years younger! :-)

My 82163 has some jitter. I've replaced one of the rather expensive IC's to no avail. Unable to find a schematic. Kinda bummed. You say a monitor could make me feel 30 years younger? Perhaps I should keep an eye peeled for one; even with the jitter that could lift my spirits regarding the interface. Thanks, Michael.

[Marcus von Cube]

(03-30-2015 09:28 PM)Dave Frederickson Wrote:  My 82163 has some jitter.

Jitter may be the result of the power supply frequency being different from the refresh rate of the video interface. If you have a 50 Hz video signal on a display connected to 60 Hz power you may see a constantly wobbling image. This is my experience from the late 70s when monitors were essentially cheap TV sets without a tuner.

[Dave Frederickson]

(03-31-2015 08:02 PM)Marcus von Cube Wrote:  

(03-30-2015 09:28 PM)Dave Frederickson Wrote:  My 82163 has some jitter.

Jitter may be the result of the power supply frequency being different from the refresh rate of the video interface. If you have a 50 Hz video signal on a display connected to 60 Hz power you may see a constantly wobbling image. This is my experience from the late 70s when monitors were essentially cheap TV sets without a tuner.

Thanks, Marcus. The 82163 is an "A" so both the refresh rate and power line frequency are 60Hz. I was going to try the TV Out to see if it was jittery, too. Any suggestions would be greatly appreciated.

Dave

[Paul Berger (Canada)]

(03-31-2015 08:27 PM)Dave Frederickson Wrote:  

(03-31-2015 08:02 PM)Marcus von Cube Wrote:  Jitter may be the result of the power supply frequency being different from the refresh rate of the video interface. If you have a 50 Hz video signal on a display connected to 60 Hz power you may see a constantly wobbling image. This is my experience from the late 70s when monitors were essentially cheap TV sets without a tuner.

Thanks, Marcus. The 82163 is an "A" so both the refresh rate and power line frequency are 60Hz. I was going to try the TV Out to see if it was jittery, too. Any suggestions would be greatly appreciated.

Dave

Nearby transformers will will also cause waving and jitter on a CRT it does not take a lot either, I have seen power cube for a portable CD player mess up the image on a 19" Sony CRT. Nearby motors both universal and synchronous will do that too. I remember taking a call where a customer complained her CRT was wavey and when I arrived at her desk I spotted a small air cleaner beside her terminal so I turned it off and asked her if that was better, and of course it was. The oddest one was a desk that was adjacent to a wall with an elevator shaft on the other side, the CRT would go nuts when the elevator car went by.

[Dave Frederickson]

(03-31-2015 09:01 PM)Paul Berger (Canada) Wrote:  Nearby transformers will will also cause waving and jitter on a CRT it does not take a lot either, I have seen power cube for a portable CD player mess up the image on a 19" Sony CRT. Nearby motors both universal and synchronous will do that too. I remember taking a call where a customer complained her CRT was wavey and when I arrived at her desk I spotted a small air cleaner beside her terminal so I turned it off and asked her if that was better, and of course it was. The oddest one was a desk that was adjacent to a wall with an elevator shaft on the other side, the CRT would go nuts when the elevator car went by.

Thanks, Paul, but I'm using my desktop LCD monitor, not a CRT.

[Marcus von Cube]

(03-31-2015 09:08 PM)Dave Frederickson Wrote:  Thanks, Paul, but I'm using my desktop LCD monitor, not a CRT.

I've recently seen high frequency jitter on a LCD monitor attached to s standard VGA character, not graphics, output of an older PC. The LCD was unable to correctly sync to the output signal. If you want to debug your interface, connect it to an analog monitor which allows to sync to low frequency video signals.

[Dave Frederickson]

(03-31-2015 09:14 PM)Marcus von Cube Wrote:  If you want to debug your interface, connect it to an analog monitor which allows to sync to low frequency video signals.

I was able to find a National Electronics NL214C monitor which was intended for CCTV applications, the horiz resolution is only 450 lines. Inputs are BNC so I had to dig up an RCA-BNC adapter.

Dang! It works fine with the CRT and my TV, well, for the most part. Thank you, gentlemen, for your advice.

[rprosperi]

Looking at the freshly edited pics in this listing on eBay, I would say someone just got a monitor...

Just sayin....

[Michael Fehlhammer]

You are right, Bob: :-)
The seller of the big bundle was so kind to sell me the monitor separately.