Ignition Warning light on, tach working

[92rrcl]

I have a ’92 Classic and the Ignition Warning light on my dash came on several weeks ago. The tachometer is still functioning and the battery continues to be charged. When driving the vehicle with the engine running at ~ 2200 rpm there is a ‘hesitation’ when an electrical load is put on the system (wipers, ABS, etc.). I checked connections on the alternator and all appear to be good. I am at a loss as to what to check next. If you would, please help me with some direction on this one! Thanks.

[Disco]

One of the diodes inside the alternator is dead, hence the 'surge' when it suddenly gets a load.

[92rrcl]

Thanks for the help!