Compaq Portable 386- Power Supply

I bought a vintage Compaq Portable 386 a few months back as a curiosity, and I've run into some problems. The machine was working fine for a couple of months but now refuses to power on.

I completely removed the power supply to see what the problem was. Since this is an old AT-class machine, the power switch is integrated into the power supply itself (e.g. it does not have to be connected to a motherboard to power up.)

When the power switch is thrown, there is a *click* from within the supply but that's it. The fan refuses to spin up.

The click noise is normal and is caused by an electro magnetic relay mounted on the supply.

I've opened the the case to check for any obvious problems (Blown capacitors, ect.; but everything looks good.)

If anyone has any ideas on what component might have failed, I'd love to know. Finding another power supply for this machine isn't really an option since they were custom manufactured to fit the portables case.
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  1. Your best chances are to find an expert who can hunt down the fault. The other is that if you are lucky enough to find a replacement. 386 era parts can be hell to track down :(
  2. hi,
    This is very funny because on my side, I do exactly the same thing in the same time...(I’ve test my “new” Compaq 386 the 24 march…)
    I notice that my power supply is really damaged : transistors had burn and so one...
    This is why I toke an old ATX power supply that I've mount on the Compaq power supply case. Lucky I am: the bow is at the good dimensions…! :bounce:
    This is fine except that now I could no connect this supply with the motherboard: the 12 pins haven't any marquee to indicate where is the 12V, 5V, 0V, -5V (if any) and 3,3V (if any too...). And the same for the display screen cable.
    If you are lucky and now your power supply is working, or if anyone else can do this, It will be very kindly to inadequate de junction that we had to make on this connector...
    E.g.: from left to right : 1 => 0V, 2 => 5V….

    PS : Sorry for my bad English, I'm a poor French...
  3. I suggest a yoobao portable power supply from ebay seller----superdealer
  4. justmore said:
    I suggest a yoobao portable power supply from ebay seller----superdealer

    impossible, the existing power supply had and extra connector to send some specifical tension, around 200V= for the plasma power. For the main, it's ok, I've got the signal, but for the molex to the display, If any one can give me the correct tension on each pin, it will be frendly !
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