condensor ?

How will I know wnen the condensor is bad? Truck was running fine then all of a sudden it wasnt. only getting intermitent spark at the points. sounds like it missing a couple cylinders. any ideas?

The simpe answer is to read the -20 and -34 manuals. They walk you through symptoms, how to check each part and fix it.

Realistically, the ignition system is usually a go or no go kind of thing. Check you fuel system for a progressive problem.

I had similar symptoms a little while ago. I was sure it was a fuel problem, cleaned the carb a couple times, changed out 2 fuel filters, tried feeding fuel from a pressurized can, no luck. A guy I work with suggested the condensor, I figured it couldn't be the problem, I just went through the ignitor in the fall and didn't drive the truck all that much after. I tried putting the old one in, and the engine ran perfect. I did pull a couple plugs earlier and noticed that the spark looked weak, but I disregarded it. Like Barrman said, I thought if it was an ignition problem, the engine wouldn't have run at all.

put in the condenser off my old distributer and it is running as least as good as it did before the problem started.

I've probably replaced more good condensors than bad ones. Seems that if they are working, then there isn't any need to change one out "just because" Unless the points are really badly pitted, I don't generally change the condensor.

I also think that the replacements these days are Chinese and of dubious quality.

In 50 years of wrenchin', I've always changed the condenser when I replaced points. "Way back then," a standard tuneup included new points, plugs and condenser. "Nowadays," the spark plugs last much longer than they used to, but points still have pretty much the same life span. Condensers are a horse of a different color. Like Randyscycle, I've probably changed out a lot of good ones, but they're strange beasts. A condenser can be perfectly good for 50 years and be totally shot in the blink of an eye. A brand new one can go south just as fast. Some of the new ones (made in China) are bad right out of the box!

With bad points even a good condensor can not help. However, good points never will work with bad condensors.
First easy check, for that is an electrolytic condensors: Is the condensor a short, replace it. For that you should take ist out and measure it. If the electrolytic condenso is over 20 or 30 years old, you can expect it that the condensor is dry and therefor has a short.
If bad, change to any 4.7 mF electrolyte condensor cast in resigne (good for any replacement). If no help, check points for burn out. If no help, check voltage to points (and capacity of the batterie as well as charge under load from the altinator.).
If everything is ok, check ignition wires (you also can do this first, if any spark plug smells like to much fuel, the wire is to be replaced.).
Thats the procedure.
Good luck
Wolf