I should have asked you, what is actaully wrong with your DT400. No spark? If no spark did you troubleshoot EVERYTHING before thinking about changing it over to points. Imagine it´s just a bad ignition coil or worse a dirty connection. If the pulser is bad then I would change the ignition to the DT 250 points and condenser setup .The pulser should have 90 ohms of resistance between the two coil ends (where the two wires are soldered onto it). Those CDI boxes usually do not go bad but if everything else checks out it could be bad. I have an extra CDI box that I know is good because I tested it. You can even check the source coil and if that is bad it can be rewound but I guess you still have that troublesome pulser that could go at any time.