I have run into the same problems that everyone is posting. I did run across a Chinese manufacturing web sit that claimed to be a source for the part, but orders of several hundred parts were required. Could not fine a retail outlet for this guy.

The carbon is not worn thru on my unit, but the readings are erratic. Book says that the ohm reading should be continuously increasing to the half way point and then start to decrease. The actual reading starts at 1.30K then increase to 1.50k, 1.80K, 2.00K, then decrease to 1.60K and then jump to 3.00K. This type of erratic reading go all the way up the scale to the half way point where the start to decrease per the spec. Is this erratic reading normal? Or should it be the reading be one smooth contentious increase? If I set the meter to A higher scale it does read correctly 1K,2K,3K,4,K,5K,6K. Am I making my own problem?

Thanks for the response