Re: My original IIGS monitor just blew up!

["Michael J. Mahon" <mjmahon@aol.com>]

bloomer_au wrote:
> After finally getting the game Moebius back on to 5.25" floppies with
> ADTPro, I had a marathon of it on my IIGS this eve. After 2.5 hours,
> the monitor started making a schlorpy sound. This became hissing,
> which became smoke and a flash and a bang. My monitor died and emitted
> a horrible smell. Fortunately I was able to save my game just before I
> could no longer see...
>
> However, I now need to get a new VDU for my IIGS.
>
> I was wondering what kind of options I have? Is there something modern
> I could jury-rig or connect it to with an adapter cable? I'd probably
> rather do something like that than try to find another original IIGS
> monitor which will necessarily also be 20+ years old at this point.
> Plus they're so small :)
>
> I can't believe that monitor, and my IIGS, are 21 years old this year.

The horrible smell suggests to me that you have a problem which
is pretty easy to fix.

It sounds like the 0.2uF "X2"-type capacitor across the AC line
input in the power supply has shorted (momentarily, before burning
out).  The current drawn to accomplish this blew the line fuse.

To fix it, you need to open the power supply (don't know whether
this is open in the monitor box or contained in a smaller metal box).

Look near where the AC power enters the power supply.  You'll find
a blown fuse and a still-stinky damaged looking prismatic plastic
capacitor on the board.  This capacitor should be unsoldered and
examined for its capacitance and voltage ratings--you'll need to
order a replacement (or two ;-).

When the capacitor is removed, you can replace the fuse and try the
monitor--it should power up and operate normally.

When the replacement capacitor arrives, solder it in and you're
good to go.

This kind of failure is relatively common to many kinds of older
computer equipment with switching power supplies.

It's worth repeating:  almost all failures of electronic equipment
are the result of the failure of a single component, with possible
collateral damage to one or two immediately adjacent components.

Learning to repair vintage electronic equipment is almost necessary
if you plan to keep it in working condition.  The web is your friend!

Also, "preventive" replacement is usually folly--"If it ain't broke,
don't fix it."  After it's broken, the problem is much easier to
identify!  ;-)

-michael

NadaNet 3.1 for Apple II parallel computing!
Home page:  http://home.comcast.net/~mjmahon/

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