CGA computer monitor

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Mikeley
    ESR Man
    • Oct 2010
    • 41

    #1

    CGA computer monitor

    Hi,

    Anyone remember CGA? I havent seen one in years. This is an industrial CRT monitor with some problems. Model is Lucius & Baer CC14VAO-CH.

    It came to me dead. After replacing many electrolytic caps, it came back to life. I generally check capacitance and ESR on all once I find a few suspect.
    Probably more trouble than it's worth, but I like old stuff. This monitor requires a H-sync signal before it will run.

    The only CGA source I have is a BK Percision 1275. I made up a connection from a serial cable and built a 'gender adaptor' to sort out male/female issue at the monitor. Now, this could be the issue!

    In the attached pictures, on solid primary colours, and white, there is a solid wide vertical bar down the screen. This can be moved across the screen with H-Pos pot at the rear of the monitor. On other test patterns, vertical lines look split, and on the color test, RGB looks just a bit odd as in the attached image.

    I'm not an expert on monitors, so would appreciate your help. See attached pictures. Any opinions, checks, what should I expect?

    Have an basic tools, oscilliscope, DVM etc. and willing to learn more!

    M
    Attached Files
  • kc8adu
    Super Moderator
    • Nov 2003
    • 8832
    • U.S.A!

    #2
    Re: CGA computer monitor

    not cga.maybe ega or vga.possible nonstandard scan rate.
    the image shows its set to the wrong scan rate.
    edit.
    its a vga.
    i remember fixing one a while back.was in a husky plastic molding machine.
    Last edited by kc8adu; 11-24-2010, 05:28 PM.

    Comment

    • Wizard
      Badcaps Legend
      • Mar 2008
      • 2296

      #3
      Re: CGA computer monitor

      Your interlace is off, need to find more small value capacitors around the IC that takes inputs and outputs horizontal and vertical pulses.

      CGA is TV chassis type without tuner, video is fed in either by composite or TTL. The timing is same as TV.

      15.7Khz 60Hz. Plucked from wiki on CGA:

      "Type Digital, TTL
      Resolution 640h x 200v, 320h x 200v
      H-freq 15.75 kHz
      V-freq 60 Hz
      Colors 16"

      Cheers, Wizard

      Comment

      • kc8adu
        Super Moderator
        • Nov 2003
        • 8832
        • U.S.A!

        #4
        Re: CGA computer monitor

        its probably ok if he treats it as vga.

        Originally posted by Wizard
        Your interlace is off, need to find more small value capacitors around the IC that takes inputs and outputs horizontal and vertical pulses.

        CGA is TV chassis type without tuner, video is fed in either by composite or TTL. The timing is same as TV.

        15.7Khz 60Hz. Plucked from wiki on CGA:

        "Type Digital, TTL
        Resolution 640h x 200v, 320h x 200v
        H-freq 15.75 kHz
        V-freq 60 Hz
        Colors 16"

        Cheers, Wizard

        Comment

        • Mikeley
          ESR Man
          • Oct 2010
          • 41

          #5
          Re: CGA computer monitor

          Yes, confirmed the H-sync at 15.76Hz, and V sync at 60.1Hz. The CGA system is based upon TTL level signals. This is smilar to EGA with the intensity pin 6 providing additional colors. It's a TV without a tuner! It's not possible to treat this as a VGA input signal.

          H and V signals go trough an XOR arrangement and then on through a 74LS123 'one shot'. From there a NPN transistor provides drive, possible level shift. Will have to explore the board some more to understand the circuit. It's a real pain to access!
          There is an analog multiplexer (4051BE) in there also. Not sure why. Guessing this could be a switch depending on scan rates?

          I did try to vary H-hold pot on the PCB, to get a lock on the images I attached. I also tried EGA source from the BK1275 but could not get a lock. Measured H-freq at 21.82kHz and V-freq at 59.6Hz. Checked on a scope etc.

          From your experience, is this issue more likely to be H-sync related? Will be checking Vertical and Horizontal deflection IC specs.

          Comment

          • Wizard
            Badcaps Legend
            • Mar 2008
            • 2296

            #6
            Re: CGA computer monitor

            Yes!! Horizontal is way off. Should be 15.7KHz.

            Where is 22KHz pulses coming from while inputting 15.7KHz H and 60Hz V? That's your hint, trace back.

            PS: EGA wiki:

            "Type Digital, TTL
            Resolution H x V 640 x 350 other modes available
            H-freq 15.7 or 21.8 kHz
            V-freq 60 Hz
            Colors 6-bit (64)"

            Cheers, Wizard
            Last edited by Wizard; 11-24-2010, 07:03 PM.

            Comment

            • kc8adu
              Super Moderator
              • Nov 2003
              • 8832
              • U.S.A!

              #7
              Re: CGA computer monitor

              again its vga not cga!
              try 31.5 h

              Comment

              • Wizard
                Badcaps Legend
                • Mar 2008
                • 2296

                #8
                Re: CGA computer monitor

                You got me stumped! 1 second google confirmed that.

                Yes, go old fashioned VGA timing. Unusual to use 9 pin plug on a VGA.

                Cheers, Wizard

                Comment

                • kc8adu
                  Super Moderator
                  • Nov 2003
                  • 8832
                  • U.S.A!

                  #9
                  Re: CGA computer monitor

                  all sorts of nonstandard connectors on industrial stuff.
                  i have about 30 custom cables i made just to test/service oddball monitors.got an allen-bradley on the bench right now.oem panasonic but custom cable needed to service it.made one 15+ years ago.

                  Comment

                  • Mikeley
                    ESR Man
                    • Oct 2010
                    • 41

                    #10
                    Re: CGA computer monitor

                    This thing has a hex buffer behind the 9 pin d-type input at the rear... it only accepts TTL level logic. The pin out matches with CGA and EGA standards which both have lower sync frequencies.

                    You have a point though, I also have seen some wierd industrial stuff. Just need to figure out how to get 31.5kHz into it?

                    Comment

                    • Mikeley
                      ESR Man
                      • Oct 2010
                      • 41

                      #11
                      Re: CGA computer monitor

                      Originally posted by kc8adu
                      again its vga not cga!
                      try 31.5 h
                      Monitor all ran fine when returned to owner. The H-sync was 31.4-31.5KHz. Monitors such as these do not conform to CGA/EGA standards, in this case, recapping and the occasional faulty power supply seem to be the only issues. The TTL levels, and pin outs match these standards but timing is everything!

                      Comment

                      • Scenic
                        o.O
                        • Sep 2007
                        • 2642
                        • Germany

                        #12
                        Re: CGA computer monitor

                        Originally posted by Wizard
                        Yes, go old fashioned VGA timing. Unusual to use 9 pin plug on a VGA
                        Old Eizo CRT monitors used this. i remember having an old (early 90s?) FlexScan 5070S or something (16" IIRC) which was a VGA monitor, but had a 9pin socket at the back (+ BNC connectors).
                        it worked but developed serious issues with the picture becoming wobbly/trembling sideways till you moved the picture to one side a bit with the front controls. then it stopped for a while (an hour or so). ended up parting with it and buying a much newer Eizo F520 17" CRT. was just too annoying to play around with the settings till the pic stopped shaking all over the place..

                        i still have the original adapter and cable that came with it somewhere. 9pin cable (2x male .. i think it was wired up 1:1) and the adapter was 9pin (female) to 15pin (male).

                        edit: found the adapter. tried opening it up to see how it's wired up, but one of the screws is covered in something .. seems like glue.. destroyed the screwhead trying to get it out.. damnit.
                        i guess i have to cut a slit in the head with my dremel some day..

                        Last edited by Scenic; 02-23-2011, 04:02 PM.

                        Comment

                        • HMTR
                          New Member
                          • Oct 2011
                          • 1

                          #13
                          Re: CGA computer monitor

                          Hate to bump an old thread, but how did you come up with the pinout for the 9 pin on the back of this unit? I've been looking everywhere for this.

                          Thanks!

                          Comment

                          • mtorr
                            New Member
                            • Apr 2012
                            • 1
                            • America

                            #14
                            Re: CGA computer monitor

                            I hadn't had any luck with trying to fix our old CRT CC14V, I ended up just making a cable that ended up being a 15 pin to a 9pin.

                            Comment

                            • niko
                              New Member
                              • Oct 2012
                              • 1
                              • Russia

                              #15
                              Re: CGA computer monitor

                              Please help me find a diagram of the electrical monitor Lucius & Bar CC14VAO-CH or converter circuit CGA-VGA.
                              Last edited by niko; 10-30-2012, 12:50 AM.

                              Comment

                              Related Topics

                              Collapse

                              • momaka
                                HannStar Hanns-G HC194d LCD monitor repair
                                by momaka
                                Normally, I never post repairs this quick after I do them, because… I am usually very slow. But today, I’m making an exception here. Why? No idea. Perhaps only because the repair details are still “fresh” in my head… which is ironic, given this is a 16 year old monitor that hardly anyone will care about today. It is new to me, though. I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
                                03-15-2023, 10:17 PM
                              • ant3202
                                HP 27es - LED monitor - Monitor Flashing On - Off
                                by ant3202
                                Hi Everyone

                                Lately I am experiencing the deja-vu incident on one of the led monitor like this.
                                https://www.badcaps.net/forum/troubl...lashing-on-off

                                The monitor is HP 27es LED Monitor
                                https://h30434.www3.hp.com/t5/Deskto...e/td-p/6804692

                                The monitor will randomly blackout and display no signal and will recover again.
                                Sometimes need to power and off again to restore the display but...
                                03-20-2025, 07:30 PM
                              • Rick_1234
                                LG 23MP55HQ LED Monitor turns off after a few seconds or flickers.
                                by Rick_1234
                                Good evening, gentlemen.

                                I have a problem with my monitor. It turns off after a few seconds or flickers. Shining a flashlight on the screen doesn't show any image, so I guess it's not the "2 seconds to dark" I read in the forum.

                                To turn it back on, I have to press the power button twice. Then after a few seconds it turns off again or flickers. See video.
                                https://drive.google.com/file/d/1L6S...ew?usp=sharing


                                Things I tried

                                - Bought a new AC adapter thinking that was the problem but the problem...
                                06-22-2024, 04:44 PM
                              • momaka
                                Wise Wing F199 19'' LCD monitor - recapped
                                by momaka
                                Looking through my repair pictures and notes, it's been a long time since I posted anything in the LCD monitors section. So here goes that.

                                I'm dedicating this thread to one of the very first LCD monitors I repaired (if not the first one), which was more than 10 years ago now. The monitor is a Wise Wing, model F199. It's a 19” CFL-backlit LCD. I got it for free off of Craigslist in 2009 from a guy, who said he bought it for cheap from Wallmart and the monitor worked only for a little less than 2 years before quitting.

                                When I saw the Craigslist post, I wasn't...
                                08-24-2020, 10:58 AM
                              • sew333
                                Pc shutdown, monitor flickered with no signal after 10 seconds
                                by sew333
                                My pc:
                                10850K stock 4800mhz stock Kraken X73 good temps
                                2x16 GB DDR4 GSKILL 3000mhz XMP
                                Seasonic Tx-850 Ultra Titanium
                                Gigabyte Rtx 3090 Gaming OC
                                Aorus Z490 Pro Gaming
                                1 TB SSD


                                4 weeks ago i launched Metro Exodus Enhanced and during cinematic advertisement part ( 30 fps ), pc just shutdown.
                                Also monitor flickered with NO SIGNAL 10 seconds after shutdown. So only monitor and pc was affected.

                                Next i pressed only power button, rebooted again and its fine again. Happened once and i cant reproduce.


                                Power...
                                02-22-2022, 10:27 AM
                              • Loading...
                              • No more items.
                              Working...