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Assuming you don't have a blocked vent this could be caused by an issue with the draft pressure switch. The draft switch has (2) small vacuum tubing connected to it and it's located at the top left of the burner compartment. Once the inducer fan gets going try jumping the 2 leads on the draft switch. Tell me what happens.
Try jumping the leads on the LIMIT side of the fan/limit control. Be sure to just jump the leads on the right side of the control (which are 24 volt). The left (fan) side is line voltage.
The limit is wired in series with the pressure switch
You probably have a problem with the ignition controller but it's so old I don't know if a replacement is available or what that replacement might be. I'm going to open this backup to my colleagues so one of them can help. Please don't respond (even to acknowledge this post)until you get a response from us. If you respond first it will only delay your answer.
Something else came to mind that you can also check if you have a meter. Check for 24 volts AC at the transformer (my diagram shows blue & yellow leads). Also some models have a fuse or circuit breaker in the control box.
If you have 24 volts at the switch hen the transformer is working OK. It still looks like you have an ignition control problem.
I understand. You weren't likely to find the control anyway except perhaps online. You tech might have local access.