.. .
Hi, I have an IO-4555 Heathkit O-Scope that started spewing out smoke
15 seconds after turning it on.

Pull the cover, apply power. Look at where the smoke is coming out. If
it's coming out of the power transformer, which it almost certainly is,
pull the tubes and discard it. Nothing else is really worth saving, not
even the switches and connectors.

If it's just a power supply cap failing, you may be in luck. But what
mostly fails on those things are the high voltage secondary winding on the
power transformer, which were very close to breaking down even when they
were new. There are very narrow safety margins on those things. Everything
in these scopes was designed to be cheap.

Would like to find someone that can shoot me a PDF of the assembly
manual with schematics. The operations manual would be nice also.

I've checked Google and Dogpile for variations and can only find a
schematic for the dual trace version. (IO-4550)

That should be sufficient since what is failing is almost certainly in the
power supply anyway, which should be identical.

A few places are selling the manuals for a goofy amount of money. I
may have some files, templates, webspace, etc. that I can offer for
trade.

Heath is still around and still selling manuals, and consequently they have
been going after people who make them available for free since they are still
in copyright. I'm okay with that, because they DO make them available at
what would be a reasonable price for any piece of equipment that is worth
something. The problem is that those scopes aren't really worth anything....
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."