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Thread: IBM 5154 Troubleshooting

  1. #1
    Join Date
    Nov 2003
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    Default IBM 5154 Troubleshooting

    Having recently got hold of a couple of Paradise EGA cards, I thought I'd try and hook up the IBM 5154 EGA monitor to my 6MHz 5170.

    The previous owner dismantled the machine 10-15 years ago, and I rebuilt it from a box of parts 6 months ago. The original IBM EGA card had died, so I've been using it with VGA.

    Both of the 'new' Paradise EGA cards seem to work - I've tested them with a 5151 and 5153 with no problems.

    When I originally hooked up the 5154 6 months ago, it started smoking so I had assumed it to be dead.

    With the arrival of the new cards I did a little experimenting before Christmas. With the EGA card switches set to 'high' EGA resolution, it worked! Picture seemed good, but with a slight flickering to the left hand edge of the screen which made the first letter on each line unreadable. Adjustment with the controls on the back and inside the monitor didn't make any difference. Monitor then started smoking from around the power cord area, so immediately switched it off.

    The next day I powered it up, and it was working again. So I set the card switches to EGA 'low' resolution (it appears to be the same resolution as CGA, but with the EGA colour palette) and that was working great. In fact, the computer was on for several hours like that.

    On returning from my holiday a week later, I booted up the AT (with EGA still at low-res) and everything is good. A couple of hours of constant running I shut down the machine and set it back to 'high' resolution. This time the screen is a blur (looks like V-Sync is out as the text is racing along) and I could smell something wasn't good inside it and would probably smoke again. I powered off, but then re-set to 'low' EGA resolution and it has been fine ever since.

    Any ideas what is wrong? I thought it could be something in the power supply unit of the monitor as that is where it was smoking from, but if so I assume that would also effect the low-resolution? How come high-res smokes but low-res does not?

    I'd like to repair it if possible (or safe), but if not I am more than happy with low-res EGA!

  2. #2

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    I've had wavy edges (and sometimes text "twinkling") from excessive ripple in the power supply. Smoking from the psu area would also suggest bad capacitors.
    "Don't it always seem to go
    That you don't know what youíve got Ďtil itís gone" (BANG )

  3. #3
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    I have a 5154 monitor which smoked about ten minutes after I plugged it in.
    Lots of smoke.....
    It worked great for those first ten minutes though

    After opening the monitor I found that there was a capacitor in the power
    supply which had overheated, burst open and was leaking oil which was causing the smoke.
    Its a unique capacitor, rectangular shaped, which I think actually contains two capacitors internally
    and is oil filled. It says "0.1 uf X 2" on the top.

    I haven't found a replacement capacitor for this yet, but I was able to
    get the monitor working again using a power supply from another 5154
    I have. I've worked on several 5154's , and they ALL had one or more
    bad electrolytic capacitors in the power supply. If you're serious about
    fixing the monitor....For a few dollars its a good investment to just replace
    all the electrolytic capacitors in the power supply. However ,you can probably
    ignore those two large (220 mf) capacitors as they cost about 4 bucks apiece.
    Unless of course they are obviously leaking.

  4. #4

    Default

    X2 isn't "times 2" it means that the capacitor is suitable for going directly across a mains input. it's a filter capacitor, and can be removed for testing purposes, and eventually replaced (when you get fed up of not being able to receive anything on AM radio) with another 0.1uF X2 capacitor.
    "Don't it always seem to go
    That you don't know what youíve got Ďtil itís gone" (BANG )

  5. #5
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    Thanks for the info. Looking at the schematic I see that there
    are two of these X2 caps and they are both across the AC input.

    Quote Originally Posted by nige the hippy View Post
    X2 isn't "times 2" it means that the capacitor is suitable for going directly across a mains input. it's a filter capacitor, and can be removed for testing purposes, and eventually replaced (when you get fed up of not being able to receive anything on AM radio) with another 0.1uF X2 capacitor.

  6. #6
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    Default

    If you need a replacement, search using 'mains suppression capacitor'.
    You'll see that there are different classes of mains suppression capacitor: X1, X2, Y1, ...

    Mains suppression capacitors seem to be a high failure item in certain pieces of old equipment, just ask owners of the Osborne 1.

    But it sounds to me like 'hi-res EGA' could be using higher sync frequencies that 'normal' EGA (V=60Hz, H=15.7/21.8Khz) and as a result that your 5154 is being run beyond what it was designed for. Does your documentation indicate the frequencies used?

  7. #7
    Join Date
    Nov 2003
    Location
    London, England
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    Thanks for the replies!

    Quote Originally Posted by modem7
    But it sounds to me like 'hi-res EGA' could be using higher sync frequencies that 'normal' EGA (V=60Hz, H=15.7/21.8Khz) and as a result that your 5154 is being run beyond what it was designed for. Does your documentation indicate the frequencies used?
    The "low-res" I get with the 5154 exactly the same output on screen when I run my 5153 through the EGA card on AutoSync. CGA resolution, but with the EGA colour palette. The "high-res" is I assume the standard resolution expected with an IBM 5154, but causes the left edge of the screen to flicker and the PSU to smoke.

    Quote Originally Posted by mikey99
    After opening the monitor I found that there was a capacitor in the power
    supply which had overheated, burst open and was leaking oil which was causing the smoke.
    Its a unique capacitor, rectangular shaped, which I think actually contains two capacitors internally
    and is oil filled. It says "0.1 uf X 2" on the top.

    I haven't found a replacement capacitor for this yet, but I was able to
    get the monitor working again using a power supply from another 5154
    I have. I've worked on several 5154's , and they ALL had one or more
    bad electrolytic capacitors in the power supply. If you're serious about
    fixing the monitor....For a few dollars its a good investment to just replace
    all the electrolytic capacitors in the power supply. However ,you can probably
    ignore those two large (220 mf) capacitors as they cost about 4 bucks apiece.
    Unless of course they are obviously leaking.
    Thanks, very useful info! I'll dismantle the PSU and replace any suspect caps. I guess if the oil-filled caps are gone I am out of luck though

  8. #8
    Join Date
    Nov 2003
    Location
    London, England
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    Default

    Quote Originally Posted by nige the hippy
    X2 isn't "times 2" it means that the capacitor is suitable for going directly across a mains input. it's a filter capacitor, and can be removed for testing purposes, and eventually replaced (when you get fed up of not being able to receive anything on AM radio) with another 0.1uF X2 capacitor.
    Oh, so I guess they can be replaced then? I'd better start scouring the Maplin catalogue

    Does anyone have a schematic they could copy for me?

  9. #9
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    I found this on Google Groups:

    IBM 5154 AND 5175 MONITORS
    --------------------------

    EGA (5154) and PGA (5175) monitors are nearly identical except for the
    video electronics contained in a metal box on the left side (when
    facing the screen). Schematics ARE available from IBM, in _Technical
    Reference, Options and Adapters, Volume 3_ of the "Personal Computer
    Hardware Reference Library." Introduced in the mid 1980's, many 5154
    and 5175 monitors are nearing the end of their service lifetimes,
    i.e., tubes have dim picture and poor focus, and numerous capacitors'
    values have decreased. In severe cases, we advise users to scrap the
    monitors and convert to VGA.

    The most common failure is in the power supply: Symptoms include
    chirping noise, repetitive startup/shutdown (blinking LED pilot lamp)
    or jagged edges on left and right of picture.

    Replace three small electrolytic capacitors in the power supply:
    C11 (47uF 40v), C13 (10uF 35v) and C14 (1uF 35v). These capacitors
    fail from heat after long service.

    The power-supply unit is removable. You must drill-out three pop-
    rivets to open the metal box; replace them with sheet-metal screws.

    Symptom: Vertical foldover in EGA mode, or incorrect vertical
    centering.

    Replace C311 (100 uf 40v) near vertical amplifier (IC300).

  10. #10

    Default

    Thanks, very useful info! I'll dismantle the PSU and replace any suspect caps. I guess if the oil-filled caps are gone I am out of luck though
    You can always get replacement caps. As I said in another posting, they're usually a little smaller than the originals. Vintage TV & wireless buffs often remove the guts of the originals & put the new component inside the old case, you've really got to avoid handling the "oil" though it's a poly-chlorinated-biphenol, it's got a long name and it's nasty!

    If you need help with getting the correct components, email me a list & I can help to give you part numbers & suppliers.
    "Don't it always seem to go
    That you don't know what youíve got Ďtil itís gone" (BANG )

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