Vintage CRT Monitor Repair Thread

Discussion in 'Retro & Arcade Worklogs' started by sean0118, Nov 13, 2016.

  1. elvis

    elvis Old school old fool

    Joined:
    Jun 27, 2001
    Messages:
    42,819
    Location:
    Brisbane
    I've found some 15-19" chassis on Aliexpress. They're about $50 or so. I'm really tempted to try one out just for the hell of it.
     
  2. OP
    OP
    sean0118

    sean0118 Member

    Joined:
    Jul 24, 2012
    Messages:
    199
    Location:
    Sydney
    The Commodore works!

    [​IMG]


    Which is surprising given the state of some of the transistors:

    [​IMG]


    The power supply cleaned up okay, I recapped it with long life Nichicon capacitors, seems to work well.

    On the CRTs main board I replaced a suspect looking electrolytic capacitor and the film capacitor that was damaged (pics earlier in thread). I forgot to order replacement transistors, two were so corroded their legs snapped off the board when I washed it. I had a suitable replacement for one, but not for the other (the one in the above photo), however its function is related to switching between CGA and EDA modes, so is not critical for the operation of the CRT.

    Just need to replace the transistors, some trimpots, add the video cable and it's done.

    [​IMG]
     
  3. flu!d

    flu!d Never perfect, always genuine

    Joined:
    Jun 27, 2001
    Messages:
    18,467
    Holy shit, that was in a bad way!

    I've never seen one of those Commodore monitors before, is that suited to Commodore's PC range?

    BTW, a warning for anyone looking for flybacks, don't buy them from the Polish seller on Ebay, they're complete garbage and take a month to arrive. Buy them from Wagner Electronics, much better quality, they last longer than two weeks and best of all they're located in Australia so they take two days to arrive at roughly the same price.
     
  4. OP
    OP
    sean0118

    sean0118 Member

    Joined:
    Jul 24, 2012
    Messages:
    199
    Location:
    Sydney
    Oh yeah, took a lot of cleaning, still needs more work though.

    It's a CM-312, manufactured 1990, does monochrome, EGA and CGA. As someone else mentioned in the thread earlier it's a rebadged AOC, but apart from that I haven't found much information on it.

    edit: There are schematics online too (for the AOC version) which is very helpful.
     
    Last edited: Nov 12, 2017
  5. flu!d

    flu!d Never perfect, always genuine

    Joined:
    Jun 27, 2001
    Messages:
    18,467
    I didn't even know AOC made monitors back then...
     
  6. kbekus

    kbekus Member

    Joined:
    Aug 28, 2001
    Messages:
    1,206
    Location:
    Pascoe Vale, Melbourne
    hey guys, can anyone recommend someone to repair my NEC Multisync 3D in Melbourne, preferably in the northern suburbs? The image has collapsed down to a single horizontal line :(
     
  7. Flamin Joe

    Flamin Joe Member

    Joined:
    Jun 28, 2001
    Messages:
    4,950
    Location:
    4300
    Almost a year ago I purchased a two complete IBM's, an IBM 5150 and a IBM 5160 with their original CRT's (5151 and 5153). I only just recently finished off the last of the repairs of the 5150 system (including having to replace the flyback and doing a full recap for good measure on the 5151) so it's on to the 5153. :thumbup:

    Symptom:

    When I first fired it up everything was working as to be expected. Then about 10 minutes in I started smelling a burning smell so I quickly switched it off. The screen was still working at the time so there was the possibility it was just built up dust heating up but I didn't want to take the risk and leave it running.


    Onto opening up. You might notice the scratches where the anode cap was. I had a hell of time getting the sucker off as the the silicon grease they had used had just about dried up and was like hard rubber!


    Click to view full size!


    First port of call is where the power comes in and bingo, found the culprit.


    Click to view full size!


    The one of the other side looks like it's on it's way out too.


    Click to view full size!


    That's about as far as I've gotten so far as this was just a first look/assessment to see what parts I will need to order. The plan is to replace these of course as well as do a full recap of all the electrolytic capacitors and any other components which require it. Not sure how much progress I will make with Christmas coming up so it may be a while until it's complete.
     

Share This Page

Advertisement: